Download pdf - 3110 -- CanOBD2® Diagnostic Tool - Equus

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Table of Contents

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Title Page No.

INTRODUCTIONWhat is OBD? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

YOU CAN DO IT! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

SAFETY PRECAUTIONSSafety First! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

ABOUT THE CODE READERVehicles Covered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Battery Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Adjustments and Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

CODE READER CONTROLSControls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Display Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

ONBOARD DIAGNOSTICSComputer Engine Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Diagnostic Trouble Codes (DTCs) . . . . . . . . . . . . . . . . . . . . . . 20OBD 2 Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

PREPARATION FOR TESTINGPreliminary Vehicle Diagnosis Worksheet . . . . . . . . . . . . . . . . 30Before You Begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

USING THE CODE READERCode Retrieval Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Erasing Diagnostic Trouble Codes (DTCs) . . . . . . . . . . . . . . . . 40I/M Readiness Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

GLOSSARYIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Glossary of Terms and Abbreviations . . . . . . . . . . . . . . . . . . . 49

WARRANTY AND SERVICINGLimited One Year Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Service Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

IntroductionWHAT IS OBD?

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WHAT IS OBD?

The CAN OBD2 Code Reader is designed to work on all OBD 2compliant vehicles. All 1996 and newer vehicles (cars, light

trucks and SUVs) sold in the United States are OBD 2 compliant.

One of the most exciting improvements in the automobile industry was the additionof on-board diagnostics (OBD) on vehicles,or in more basic terms, the computer thatactivates the vehicle’s “CHECK ENGINE”light. OBD 1 was designed to monitor manu-facturer-specific systems on vehicles builtfrom 1981 to 1995. Then came the develop-ment of OBD 2, which is on all 1996 and newer vehicles sold in theU.S. Like its predecessor, OBD 2 was adopted as part of a governmentmandate to lower vehicle emissions. But what makes OBD 2 unique isits universal application for all late model cars and trucks - domesticand import. This sophisticated program in the vehicle’s main computersystem is designed to detect failures in a range of systems, and canbe accessed through a universal OBD 2 port, which is usually foundunder the dashboard. For all OBD systems, if a problem is found, thecomputer turns on the “CHECK ENGINE” light to warn the driver, andsets a Diagnostic Trouble Code (DTC) to identify where the problemoccurred. A special diagnostic tool, such as the CAN OBD2 CodeReader, is required to retrieve these codes, which consumers and pro-fessionals use as a starting point for repairs.

To learn more about vehicle Computer Control Systems andOBD 2, see COMPUTER ENGINE CONTROLS on page 14.

You Can Do It!EASY TO USE - EASY TO VIEW - EASY TO DEFINE

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Easy To Use . . . .■ Connect the Code Reader to the

vehicle’s test connector.

■ Turn the ignition key "On.”

■ Press the LINK button.

Easy To View . . . .■ The Code Reader retrieves stored

codes, Freeze Frame data and I/MReadiness status.

■ Codes, I/M Readiness status andFreeze Frame data are displayed on theCode Reader’s LCD display screen.System status is indicated by LED indi-cators.

Easy To Define . . . .

■ Read code definitions from the CodeReader’s LCD display.

■ View Freeze Frame data.

Safety PrecautionsSAFETY FIRST!

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SAFETY FIRST!

This manual describes common test procedures used byexperienced service technicians. Many test proceduresrequire precautions to avoid accidents that can result inpersonal injury, and/or damage to your vehicle or testequipment. Always read your vehicle's service manual andfollow its safety precautions before and during any test orservice procedure. ALWAYS observe the following generalsafety precautions:

When an engine is running, it produces carbon monox-ide, a toxic and poisonous gas.To prevent serious injuryor death from carbon monoxide poisoning, operate thevehicle ONLY in a well-ventilated area.

To protect your eyes from propelled objects as well ashot or caustic liquids, always wear approved safetyeye protection.

When an engine is running, many parts (such as thecoolant fan, pulleys, fan belt etc.) turn at high speed. Toavoid serious injury, always be aware of moving parts.Keep a safe distance from these parts as well as otherpotentially moving objects.

Engine parts become very hot when the engine is run-ning. To prevent severe burns, avoid contact with hotengine parts.

Before starting an engine for testing or trouble-shoot-ing, make sure the parking brake is engaged. Put thetransmission in park (for automatic transmission) orneutral (for manual transmission). Block the drivewheels with suitable blocks.

Connecting or disconnecting test equipment when theignition is ON can damage test equipment and the vehi-cle's electronic components. Turn the ignition OFFbefore connecting the Code Reader to or disconnectingthe Code Reader from the vehicle’s Data LinkConnector (DLC).

To avoid personal injury, instrument damage and/ordamage to your vehicle; do not use the CAN OBD2 Code

Reader before reading this manual.

N LDRP

Safety PrecautionsSAFETY FIRST!

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To prevent damage to the on-board computer when tak-ing vehicle electrical measurements, always use a digi-tal multimeter with at least 10 megOhms of impedance.

Fuel and battery vapors are highly flammable. To pre-vent an explosion, keep all sparks, heated items andopen flames away from the battery and fuel / fuelvapors. DO NOT SMOKE NEAR THE VEHICLE DUR-ING TESTING.

Don't wear loose clothing or jewelry when working on anengine. Loose clothing can become caught in the fan,pulleys, belts, etc. Jewelry is highly conductive, and cancause a severe burn if it makes contact between apower source and ground.

About the Code ReaderVEHICLES COVERED

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VEHICLES COVERED

The CAN OBD2 Code Reader is designed to work on all OBD 2 com-pliant vehicles. All 1996 and newer vehicles (cars and light trucks) soldin the United States are OBD 2 compliant.

Federal law requires that all 1996 and newer cars and lighttrucks sold in the United States must be OBD 2 compliant;this includes all Domestic, Asian and European vehicles.

Some 1994 and 1995 vehicles are OBD 2 compliant. To find out if a1994 or 1995 vehicle is OBD 2 compliant, check the following:

1. The Vehicle Emissions Control Information (VECI) Label. Thislabel is located under the hood or by the radiator of most vehicles. Ifthe vehicle is OBD 2 compliant, the label will state “OBD II Certified .”

2. Government Regulations require thatall OBD 2 compliant vehicles musthave a “common” sixteen-pin DataLink Connector (DLC) .

Some 1994 and 1995 vehicles have 16-pin connectors butare not OBD 2 compliant. Only those vehicles with a VehicleEmissions Control Label stating “OBD II Certified” are OBD 2compliant.

Data Link Connector (DLC) Location

The 16-pin DLC is usuallylocated under the instrumentpanel (dash), within 12 inches(300 mm) of center of thepanel, on the driver’s side ofmost vehicles. It should be eas-ily accessible and visible froma kneeling position outside thevehicle with the door open.

VEHICLE EMISSION CONTROL INFORMATION

VEHICLEMANUFACTURER

OBD IICERTIFIED

ENGINE FAMILY EFN2.6YBT2BADISPLACEMENT 2.6L

THIS VEHICLE CONFORMS TO U.S. EPA AND STATEOF CALIFORNIA REGULATIONS APPLICABLE TO1999 MODEL YEAR NEW TLEV PASSENGER CARS.

REFER TO SERVICE MANUAL FOR ADDITIONAL INFORMATIONTUNE-UP CONDITIONS: NORMAL OPERATING ENGINE TEMPERATURE,ACCESSORIES OFF, COOLING FAN OFF, TRANSMISSION IN NEUTRAL

SPARK PLUGTYPE NGK BPRE-11

GAP: 1.1MMCATALYST

EXHAUST EMISSIONS STANDARDS STANDARD CATEGORY

CERTIFICATIONIN-USE

TLEVTLEV INTERMEDIATE

OBD IICERTIFIED

1 2 3 4 5 6 7 8

9 10111213141516

NEARCENTEROF DASH

BEHINDASHTRAY

LEFT CORNEROF DASH

About the Code ReaderVEHICLES COVERED / BATTERY REPLACEMENT

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On some Asian and European vehicles the DLC is locatedbehind the “ashtray” (the ashtray must be removed to accessit) or on the far left corner of the dash. If the DLC cannot belocated, consult the vehicle’s service manual for the location.

BATTERY REPLACEMENT

1. Locate the battery cover on the back of the Code Reader.

2. Slide the battery cover off (use your fingers).

3. Replace batteries with three AA-size batteries (for longer life, useAlkaline-type batteries).

4. Reinstall the battery cover on the back of the Code Reader.

Language Selection After Battery Installation

There are two versions of the Code Reader: English/Spanish andEnglish/French. The first time the unit is turned on (after the batteriesare installed or replaced), you must select the desired display lan-guage, as follows:

1. Press the POWER/LINK button to turn the Code Reader “ON.”

■ The Select Language screen displays.

2. Use the UP and DOWN but-tons, as necessary, to highlight thedesired display language.

3. When the desired display language isselected, press the ENTER/FF but-ton to confirm your selection.

■ The selected language will remain inthe Code Reader’s memory as longas the batteries are not removed. Ifthe batteries are removed (or godead), the language selection will belost from the Code Reader’s memoryand must be reset again using steps1 through 3, above.

■ After the initial language selection is performed, it as well asother settings can be changed as desired. See ADJUSTMENTSAND SETTINGS on page 7 for further instructions.

About the Code ReaderADJUSTMENTS AND SETTINGS

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ADJUSTMENTS AND SETTINGS

The CAN OBD2 Code Reader lets you make several adjustments andsettings to configure the Code Reader for your particular needs. Thefollowing adjustments and settings can be made:

■ Adjust Brightness: Adjusts the brightness of the LCD displayscreen.

■ Demo Mode: Sample data kept in the Code Reader’s memory touse as examples and for demonstration purposes.

■ Select Language: Sets the display language for the Code Readerto English/Spanish or English/French.

■ Unit of Measure: Sets the Unit of Measure for the Code Reader’sdisplay to USA or metric.

Adjustments and settings can be made only when the CodeReader is NOT connected to a vehicle.

To enter the MENU Mode:

1. With the Code Reader “off”, press andhold the UP button, then press andrelease the POWER/LINK button.

■ The adjustments and setting MENUdisplays.

2. Release the UP button.

DO NOT release the UP button until the adjustments andsettings MENU is visible on the display.

3. Make adjustments and settings as described in the following para-graphs.

Adjusting Display Brightness

1. Use the UP and DOWN but-tons, as necessary, to highlight AdjustBrightness in the MENU, then pressthe ENTER/FF button.

■ The Adjust Brightness screen dis-plays.

■ The Brightness field shows the cur-rent brightness setting, from 0 to 43.

2. Press the UP button to decreasethe brightness of the LCD display (makethe display darker).


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3. Press the DOWN button to increase the brightness of the LCDdisplay (make the display lighter).

4. When the desired brightness is obtained, press the ENTER/FFbutton to save your changes and return to the MENU.

Selecting the Display Language

1. Use the UP and DOWN but-tons, as necessary, to highlight SelectLanguage in the MENU, then press theENTER/FF button.

■ The Select Language screen dis-plays.

■ The currently selected displayLanguage is highlighted.

2. Press the UP or DOWN button,as necessary, to highlight the desireddisplay language.

3. When the desired display language ishighlighted, press the ENTER/FFbutton to save your changes and returnto the MENU.

Setting the Unit of Measure

1. Use the UP and DOWN but-tons, as necessary, to highlight Unit ofMeasure in the MENU, then press theENTER/FF button.

2. Press the UP or DOWN button,as necessary, to highlight the desiredUnit of Measure .

3. When the desired Unit of Measurevalue is selected, press the ENTER/FF

button to save your changes.


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Demo Mode

1. Use the UP and DOWN but-tons, as necessary, to highlight DemoMode in the MENU, then press theENTER/FF button.

2. The Code Reader enters the DemoMode.

3. Demo Mode demonstrates examples of Generic and Enhanced(Manufacturer Speciific) Diagnostic Trouble Codes, code definitions,Freeze Frame data and I/M Readiness status.

■ Use Demo Mode to familiarize yourself with Code Reader oper-ation, vehicle diagnostic data and/or for demonstration purposes.

4. To exit Demo Mode , turn the Code Reader off by pressing thePOWER/LINK button.

Exiting the MENU Mode

1. Use the UP and DOWN buttons, as necessary, to highlightMenu Exit in the MENU, then press the ENTER/FF button.

■ The LCD display returns to the DTC screen.

Changes made to Brightness, Language and Unit ofMeasure will remain in the Code Reader’s memory as longas the batteries are not removed. If the batteries are removed(or go dead), the settings will be lost from the Code Reader’smemory, and they must be reset again.

Code Reader ControlsCONTROLS AND INDICATORS

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CONTROLS AND INDICATORS

See Figure 1 for the locations of items 1 through 11, below.

1. ERASE button - Erases Diagnostic Trouble Codes (DTCs),and “Freeze Frame” data from your vehicle’s computer, and resetsMonitor status.

2. DTC SCROLL button - Displays the DTC View screen and/orscrolls the LCD display to view DTCs when more than one DTC ispresent.

3. POWER/LINK button - When the Code Reader IS NOT connected to a vehicle, turns the Code Reader “On” and “Off ”. Whenthe Code Reader is connected to a vehicle, links the Code Reader tothe vehicle’s PCM to retrieve diagnostic data from the computer’smemory.

4. ENTER/FREEZE FRAME button - When in MENU mode,confirms the selected option or value. When retrieving and viewingDTCs, displays Freeze Frame data for the highest priority code.

1

6

7

2

5

3

9

8

4

10

11

Figure 1. Controls and Indicators

Code Reader ControlsCONTROLS AND INDICATORS

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5. DOWN button - When in MENU mode, scrolls DOWN throughthe menu and submenu selection options. When retrieving and view-ing DTCs, scrolls down through the current display screen to displayany additional data.

6. UP button - When in MENU mode, scrolls UP through themenu and submenu selection options. When retrieving and viewingDTCs, scrolls ups through the current display screen to display anyadditional data.

7. GREEN LED - Indicates that all engine systems are running nor-mally (all Monitors on the vehicle are active and performing their diag-nostic testing, and no DTCs are present).

8. YELLOW LED - Indicates there is a possible problem. A “Pending”DTC is present and/or some of the vehicle’s emission monitors havenot run their diagnostic testing.

9. RED LED - Indicates there is a problem in one or more of the vehi-cle’s systems. The red LED is also used to show that DTC(s) are pres-ent. DTCs are shown on the Code Reader’s LCD display. In this case,the Multifunction Indicator (“Check Engine”) lamp on the vehicle’sinstrument panel will light steady on.

10. LCD Display - Displays settings Menu and submenus, testresults, Code Reader functions and Monitor status information. SeeDISPLAY FUNCTIONS , on next page, for more details.

11. CABLE - Connects the Code Reader to the vehicle’s Data LinkConnector (DLC).

Code Reader ControlsDISPLAY FUNCTIONS

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DISPLAY FUNCTIONS

See Figure 2 for the locations of items 1 through 16, below.

1. I/M MONITOR STATUS field - Identifies the I/M Monitor status area.

2. Monitor icons - Indicate which Monitors are supported by the vehi-cle under test, and whether or not the associated Monitor has runits diagnostic testing (Monitor status). When a Monitor icon is solid,it indicates that the associated Monitor has completed its diagnos-tic testing. When a Monitor icon is flashing, it indicates that the vehi-cle supports the associated Monitor, but the Monitor has not yet runits diagnostic testing.

3. Vehicle icon - Indicates whether or not the Code Reader isbeing properly powered through the vehicle’s Data Link Connector(DLC). A visible icon indicates that the Code Reader is being pow-ered through the vehicle’s DLC connector.

4. Link icon - Indicates whether or not the Code Reader is com-municating (linked) with the vehicle’s on-board computer. When vis-ible, the Code Reader is communicating with the computer. If theLink icon is not visible, the Code Reader is not communicating withthe computer.

5. Computer icon - When this icon is visible it indicates that theCode Reader is linked to a personal computer. An optional “PC LinkKit” is available that makes it possible to upload retrieved data to apersonal computer.

6. Code Reader Internal Battery icon - When visible, indicatesthe Code Reader batteries are “low” and should be replaced.

7. DTC Display Area - Displays the Diagnostic Trouble Code (DTC)number. Each fault is assigned a code number that is specific tothat fault.

43

2 1 10 11 12

5

8

9

13

1514

6

7

Figure 2. Display Functions

Code Reader ControlsDISPLAY FUNCTIONS

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8. Test Data Display Area - Displays DTC definitions, Freeze Framedata, and other pertinent test information messages.

9. MIL icon - Indicates the status of the Malfunction Indicator Lamp(MIL).The MIL icon is visible only when a DTC has commanded theMIL on the vehicle’s dashboard to light.

10. CODE icon - Identifies the Code Number Sequence display area.

11. PENDING icon - Indicates the currently displayed DTC is a“Pending” code.

12. Code Number Sequence - The Code Reader assigns asequence number to each DTC that is present in the computer’smemory, starting with “01.” This number indicates which code iscurrently displayed. Code number “01” is always the highest prior-ity code, and the one for which “Freeze Frame” data has beenstored.

If “01” is a “Pending” code, there may or may not be“Freeze Frame” data stored in memory.

13. Code Enumerator - Indicates the total number of codes retrievedfrom the vehicle’s computer.

14. Generic DTC icon - When visible, indicates that the currentlydisplayed DTC is a “generic” or universal code.

15. Enhanced DTC icon - When visible, indicates that the currentlydisplayed DTC is a Manufacturer Specific Code.

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Onboard DiagnosticsCOMPUTER ENGINE CONTROLS

COMPUTER ENGINE CONTROLS

The Introduction of Electronic Engine Controls

As a result of increased air pollution (smog) in largecities, such as Los Angeles, the California Air ResourcesBoard (CARB ) and the Environmental Protection Agency(EPA) set new regulations and air pollution standards todeal with the problem. To further complicate matters, theenergy crisis of the early 1970s caused a sharp increase infuel prices over a short period. As a result, vehicle manufac-turers were not only required to comply with the new emis-sions standards, they also had to make their vehicles more fuel-efficient. Most vehicles were required to meet a miles-per-gallon(MPG) standard set by the U.S. Federal Government.

Precise fuel delivery and spark timing are needed to reduce vehicleemissions. Mechanical engine controls in use at the time (such as igni-tion points, mechanical spark advance and the carburetor) respondedtoo slowly to driving conditions to properly control fuel delivery andspark timing. This made it difficult for vehicle manufacturers to meetthe new standards.

A new Engine Control System had to be designed and integrated withthe engine controls to meet the stricter standards.The new system hadto:

■ Respond instantly to supply the proper mixture of air and fuel forany driving condition (idle, cruising, low-speed driving, high-speeddriving, etc.).

■ Calculate instantly the best time to “ignite” the air/fuel mixture formaximum engine efficiency.

■ Perform both these tasks without affecting vehicle performance orfuel economy.

Vehicle Computer Control Systems can perform millions of calcula-tions each second. This makes them an ideal substitute for the slowermechanical engine controls. By switching from mechanical to elec-tronic engine controls, vehicle manufacturers are able to control fueldelivery and spark timing more precisely. Some newer ComputerControl Systems also provide control over other vehicle functions,such as transmission, brakes, charging, body, and suspension sys-tems.

Electronic Computer Control Systems make it possiblefor vehicle manufacturers to comply with the tougher emis-

sions and fuel efficiency standards mandated byState and Federal Governments.

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The Basic Engine Computer Control System

The on-board computer is the heart of the ComputerControl System. The computer contains several programswith preset reference values for air/fuel ratio, spark or igni-tion timing, injector pulse width, engine speed, etc.Separate values are provided for various driving conditions,such as idle, low speed driving, high-speed driving, low load,or high load. The preset reference values represent the idealair/fuel mixture, spark timing, transmission gear selection,etc., for any driving condition. These values are programmedby the vehicle manufacturer, and are specific to each vehicle model.

Most on-board computers are located inside the vehicle behind thedashboard, under the passenger’s or driver’s seat, or behind the rightkick panel. However, some manufacturers may still position it in theengine compartment.

Vehicle sensors, switches, and actuators are located throughout theengine, and are connected by electrical wiring to the on-boardcomputer. These devices include oxygen sensors, coolant tempera-ture sensors, throttle position sensors, fuel injectors, etc. Sensors andswitches are input devices . They provide signals representing currentengine operating conditions to the computer. Actuators are outputdevices . They perform actions in response to commands receivedfrom the computer.

The on-board computer receives information inputs from sensors andswitches located throughout the engine. These devices monitor criticalengine conditions such as coolant temperature, engine speed, engineload, throttle position, air/fuel ratio etc.

The Computer Control System consists of an on-boardcomputer and several related control devices (sensors,

switches, and actuators).

OUTPUT DEVICES Fuel Injectors Idle Air Control EGR Valve Ignition Module

On-BoardComputer

INPUT DEVICES Coolant Temperature Sensor Throttle Position Sensor Fuel Injectors

INPUT DEVICES Oxygen Sensors

TYPICAL COMPUTERCONTROL SYSTEM

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The computer compares the values received from these sensors withits preset reference values, and makes corrective actions as neededso that the sensor values always match the preset reference values forthe current driving condition. The computer makes adjustments bycommanding other devices such as the fuel injectors, idle air control,EGR valve or Ignition Module to perform these actions.

Vehicle operating conditions are constantly changing. The computercontinuously makes adjustments or corrections (especially to theair/fuel mixture and spark timing) to keep all the engine systems oper-ating within the preset reference values.

On-Board Diagnostics - First Generation (OBD 1)

Beginning in 1988, California’s Air Resources Board(CARB ), and later the Environmental Protection Agency

(EPA) required vehicle manufacturers to include a self-diagnostic program in their on-board computers. The pro-

gram would be capable of identifying emissions-related faultsin a system. The first generation of Onboard Diagnosticscame to be known as OBD 1.

OBD 1 is a set of self-testing and diagnostic instructions pro-grammed into the vehicle’s on-board computer. The programs arespecifically designed to detect failures in the sensors, actuators,switches and wiring of the various vehicle emissions-related systems.If the computer detects a failure in any of these components or sys-tems, it lights an indicator on the dashboard to alert the driver.The indi-cator lights only when an emissions-related problem is detected.

The computer also assigns a numeric code for each specific problemthat it detects, and stores these codes in its memory for later retrieval.These codes can be retrieved from the computer’s memory with theuse of a “Code Reader” or a “Scan Tool.”

With the exception of some 1994 and 1995 vehicles,most vehicles from 1982 to 1995 are equipped with

some type of first generation On-Board Diagnostics.

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On-Board Diagnostics - Second Generation (OBD 2)

In addition to performing all the func-tions of the OBD 1 System, the OBD 2System has been enhanced with newDiagnostic Programs. These programsclosely monitor the functions of vari-ous emissions-related componentsand systems (as well as other sys-tems) and make this information readily available (withthe proper equipment) to the technician for evaluation.

The California Air Resources Board (CARB ) conductedstudies on OBD 1 equipped vehicles. The information thatwas gathered from these studies showed the following:

■ A large number of vehicles had deteriorating or degradedemissions-related components. These components werecausing an increase in emissions.

■ Because OBD 1 systems only detect failed components, thedegraded components were not setting codes.

■ Some emissions problems related to degraded components onlyoccur when the vehicle is being driven under a load. The emissionchecks being conducted at the time were not performed under sim-ulated driving conditions. As a result, a significant number of vehi-cles with degraded components were passing Emissions Tests.

■ Codes, code definitions, diagnostic connectors, communicationprotocols and emissions terminology were different for each manu-facturer. This caused confusion for the technicians working on dif-ferent make and model vehicles.

To address the problems made evident by this study, CARB and the EPApassed new laws and standardization requirements.These laws requiredthat vehicle manufacturers to equip their new vehicles with devices capa-ble of meeting all of the new emissions standards and regulations. It wasalso decided that an enhanced on-board diagnostic system, capable ofaddressing all of these problems, was needed.This new system is knownas “On-Board Diagnostics Generation Two (OBD 2) .” The primaryobjective of the OBD 2 system is to comply with the latest regulations andemissions standards established by CARB and the EPA.

The Main Objectives of the OBD 2 System are:

■ To detect degraded and/or failed emissions-related components orsystems that could cause tailpipe emissions to exceed by 1.5 timesthe Federal Test Procedure (FTP) standard.

■ To expand emissions-related system monitoring. This includes a setof computer run diagnostics called Monitors. Monitors perform diag-nostics and testing to verify that all emissions-related componentsand/or systems are operating correctly and within the manufactur-er’s specifications.

The OBD 2 System isan enhancement of the

OBD 1 System.

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■ To use a standardized Diagnostic Link Connector (DLC) in all vehi-cles. (Before OBD 2, DLCs were of different shapes and sizes.)

■ To standardize the code numbers, code definitions and languageused to describe faults. (Before OBD 2, each vehicle manufacturerused their own code numbers, code definitions and language todescribe the same faults.)

■ To expand the operation of the Malfunction Indicator Lamp (MIL).

■ To standardize communication procedures and protocols betweenthe diagnostic equipment (Scan Tools, Code Readers, etc.) and thevehicle’s on-board computer.

OBD 2 Terminology

The following terms and their definitions are related to OBD 2 systems.Read and reference this list as needed to aid in the understanding ofOBD 2 systems.

■ Powertrain Control Module (PCM) - The PCM is the OBD 2accepted term for the vehicle’s “on-board computer.” In addition tocontrolling the engine management and emissions systems, thePCM also participates in controlling the powertrain (transmission)operation. Most PCMs also have the ability to communicate withother computers on the vehicle (ABS, ride control, body, etc.).

■ Monitor - Monitors are “diagnostic routines” programmed into thePCM. The PCM utilizes these programs to run diagnostic tests, andto monitor operation of the vehicle’s emissions-related componentsor systems to ensure they are operating correctly and within thevehicle’s manufacturer specifications. Currently, up to elevenMonitors are used in OBD 2 systems. Additional Monitors will beadded as the OBD 2 system is further developed.

Not all vehicles support all eleven Monitors.

■ Enabling Criteria - Each Monitor is designed to test and monitorthe operation of a specific part of the vehicle’s emissions system(EGR system, oxygen sensor, catalytic converter, etc.). A specificset of “conditions” or “driving procedures” must be met before thecomputer can command a Monitor to run tests on its related sys-tem. These “conditions” are known as “Enabling Criteria .” Therequirements and procedures vary for each Monitor. Some Monitorsonly require the ignition key to be turned “On” for them to run andcomplete their diagnostic testing. Others may require a set of com-plex procedures, such as, starting the vehicle when cold, bringing itto operating temperature, and driving the vehicle under specificconditions before the Monitor can run and complete its diagnostictesting.

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■ Monitor Has/Has Not Run - The terms “Monitor has run” or“Monitor has not run” are used throughout this manual. “Monitorhas run ,” means the PCM has commanded a particular Monitor toperform the required diagnostic testing on a system to ensure thesystem is operating correctly (within factory specifications). Theterm “Monitor has not run ” means the PCM has not yet com-manded a particular Monitor to perform diagnostic testing on itsassociated part of the emissions system.

■ Trip - A Trip for a particular Monitor requires that the vehicle is beingdriven in such a way that all the required “Enabling Criteria” for theMonitor to run and complete its diagnostic testing are met. The “TripDrive Cycle” for a particular Monitor begins when the ignition key isturned “On.” It is successfully completed when all the “EnablingCriteria” for the Monitor to run and complete its diagnostic testingare met by the time the ignition key is turned “Off .” Since each ofthe eleven monitors is designed to run diagnostics and testing on adifferent part of the engine or emissions system, the “Trip DriveCycle” needed for each individual Monitor to run and completevaries.

■ OBD 2 Drive Cycle - An OBD 2 Drive Cycle is an extended set ofdriving procedures that takes into consideration the various types ofdriving conditions encountered in real life. These conditions mayinclude starting the vehicle when it is cold, driving the vehicle at asteady speed (cruising), accelerating, etc. An OBD 2 Drive Cyclebegins when the ignition key is turned “On” (when cold) and endswhen the vehicle has been driven in such a way as to have all the“Enabling Criteria” met for all its applicable Monitors. Only thosetrips that provide the Enabling Criteria for all Monitors applicable tothe vehicle to run and complete their individual diagnostic testsqualify as an OBD 2 Drive Cycle. OBD 2 Drive Cycle requirementsvary from one model of vehicle to another. Vehicle manufacturersset these procedures. Consult your vehicle’s service manual forOBD 2 Drive Cycle procedures.

Do not confuse a “Trip” Drive Cycle with an OBD 2 DriveCycle. A “Trip” Drive Cycle provides the “Enabling Criteria” forone specific Monitor to run and complete its diagnostic test-ing. An OBD 2 Drive Cycle must meet the “Enabling Criteria”for all Monitors on a particular vehicle to run and completetheir diagnostic testing.

■ Warm-up Cycle - Vehicle operation after an engine off periodwhere engine temperature rises at least 40°F (22°C) from its tem-perature before starting, and reaches at least 160°F (70°C). ThePCM uses warm-up cycles as a counter to automatically erase aspecific code and related data from its memory. When no faultsrelated to the original problem are detected within a specified num-ber of warm-up cycles, the code is erased automatically.

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Onboard DiagnosticsDIAGNOSTIC TROUBLE CODES (DTCs)

DIAGNOSTIC TROUBLE CODES (DTCs)

Diagnostic Trouble Codes (DTCs) aremeant to guide you to the proper serv-ice procedure in the vehicle’s servicemanual. DO NOT replace parts basedonly on DTCs without first consultingthe vehicle’s service manual for prop-er testing procedures for that particularsystem, circuit or component.

DTCs are alphanumeric codes that are used to identify aproblem that is present in any of the systems that are mon-itored by the on-board computer (PCM). Each trouble codehas an assigned message that identifies the circuit, compo-nent or system area where the problem was found.

OBD 2 diagnostic trouble codes are made up of five charac-ters:

■ The 1st character is a letter . It identifies the “main system” wherethe fault occurred (Body, Chassis, Powertrain, or Network).

■ The 2nd character is a numeric digit . It identifies the “type” of code(Generic or Manufacturer-Specific).

Generic DTCs are codes that are used by all vehicle manu-facturers. The standards for generic DTCs, as well as theirdefinitions, are set by the Society of Automotive Engineers(SAE).

Manufacturer-Specific DTCs are codes that are controlledby the vehicle manufacturers. The Federal Government doesnot require vehicle manufacturers to go beyond the stan-dardized generic DTCs in order to comply with the newOBD2 emissions standards. However, manufacturers are freeto expand beyond the standardized codes to make their sys-tems easier to diagnose.

■ The 3rd character is a numeric digit . It identifies the specific sys-tem or sub-system where the problem is located.

■ The 4th and 5th characters are numeric digits . They identify thesection of the system that is malfunctioning.

Diagnostic TroubleCodes (DTCs) are

codes that identify aspecific problem area.

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DTCs and MIL Status

When the vehicle’s on-board computer detectsa failure in an emissions-related componentor system, the computer’s internal diagnosticprogram assigns a diagnostic trouble code(DTC) that points to the system (and sub-system) where the fault was found. The diag-nostic program saves the code in the com-puter’s memory. It records a “Freeze Frame” ofconditions present when the fault was found, and lights the MalfunctionIndicator Lamp (MIL). Some faults require detection for two trips in arow before the MIL is turned on.

The “Malfunction Indicator Lamp” (MIL) is the accepted termused to describe the lamp on the dashboard that lights towarn the driver that an emissions-related fault has beenfound. Some manufacturers may still call this lamp a “CheckEngine” or “Service Engine Soon” light.

P 0 2 0 1BCPU

----

BodyChassisPowertrainNetwork

----

GenericManufacturer SpecificGenericIncludes both Generic and ManufacturerSpecific Codes

0123

Identifies what section of the systemis malfunctioning

Identifies the system where theproblem is located:

12 345 678

--

---

---

Fuel and Air MeteringFuel and Air Metering (injector circuitmalfunction only)Ignition System or MisfireAuxiliary Emission Control SystemVehicle Speed Control and Idle ControlSystemComputer Output CircuitsTransmissionTransmission

OBD 2 DTC EXAMPLEP0201 - Injector Circuit Malfunction, Cylinder 1

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There are two types of DTCs used for emissions-related faults: Type“A” and Type “B.” Type “A” codes are “One-Trip” codes; Type “B” DTCsare usually Two-Trip DTCs.

When a Type “A” DTC is found on the First Trip, the following eventstake place:

■ The computer commands the MIL “On” when the failure is firstfound.

■ If the failure causes a severe misfire that may cause damage to thecatalytic converter, the MIL “flashes” once per second . The MILcontinues to flash as long as the condition exists. If the conditionthat caused the MIL to flash is no longer present, the MIL will light“steady” On.

■ A DTC is saved in the computer’s memory for later retrieval.

■ A “Freeze Frame” of the conditions present in the engine or emis-sions system when the MIL was ordered “On” is saved in the com-puter’s memory for later retrieval. This information shows fuel sys-tem status (closed loop or open loop), engine load, coolant tem-perature, fuel trim value, MAP vacuum, engine RPM and DTC pri-ority.

When a Type “B” DTC is found on the First Trip, the following eventstake place:

■ The computer sets a Pending DTC, but the MIL is not ordered “On.”“Freeze Frame” data may or may not be saved at this time depend-ing on manufacturer. The Pending DTC is saved in the computer’smemory for later retrieval.

■ If the failure is found on the second consecutive trip, the MIL isordered “On.” “Freeze Frame” data is saved in the computer’s mem-ory.

■ If the failure is not found on the second Trip, the Pending DTC iserased from the computer’s memory.

The MIL will stay lit for both Type “A” and Type “B” codes until one ofthe following conditions occurs:

■ If the conditions that caused the MIL to light are no longer presentfor the next three trips in a row, the computer automatically turns theMIL “Off” if no other emissions-related faults are present. However,the DTCs remain in the computer’s memory as a history code for 40warm-up cycles (80 warm-up cycles for fuel and misfire faults). TheDTCs are automatically erased if the fault that caused them to beset is not detected again during that period.

■ Misfire and fuel system faults require three trips with “similar condi-tions” before the MIL is turned “Off.” These are trips where theengine load, RPM and temperature are similar to the conditionspresent when the fault was first found.

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Onboard DiagnosticsOBD 2 MONITORS

After the MIL has been turned off, DTCs, Freeze Frame data,and manufacturer-specific enhanced data stay in the com-puter’s memory. Most of the enhanced data can only beretrieved with special equipment such as a Scan Tool.

■ Erasing the DTCs from the computer’s memory can also turn off theMIL. See ERASING DIAGNOSTIC TROUBLE CODES (DTCs) onpage 41, before erasing codes from the computer’s memory. If aCode Reader or Scan Tool is used to erase the codes, FreezeFrame data as well as other manufacturer-specific enhanced datawill also be erased.

OBD 2 MONITORS

To ensure the correct operation of the various emissions-related com-ponents and systems, a diagnostic program was developed andinstalled in the vehicle’s on-board computer. The program has severalprocedures and diagnostic strategies. Each procedure or diagnosticstrategy is made to monitor the operation of, and run diagnostic testson, a specific emissions-related component or system. These testsensure the system is running correctly and is within the manufacturer’sspecifications. On OBD 2 systems, these procedures and diagnosticstrategies are called “Monitors.”

Currently, a maximum of eleven Monitors are used in OBD 2 systems.Additional monitors may be added as a result of Government regula-tions as the OBD 2 system grows and matures. Not all vehicles sup-port all eleven Monitors.

Monitor operation is either “Continuous ” or “Non-Continuous ,”depending on the specific monitor.

Continuous Monitors

Three of these Monitors are designed to constantly monitor their asso-ciated components and/or systems for proper operation. ContinuousMonitors run constantly when the engine is running. The ContinuousMonitors are:

Comprehensive Component Monitor (CCM)

Misfire Monitor

Fuel System Monitor

Non-Continuous Monitors

The other eight Monitors are “non-continuous” Monitors. “Non-continu-ous” Monitors perform and complete their testing once per trip. The“non-continuous” Monitors are:

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Oxygen Sensor Monitor

Oxygen Sensor Heater Monitor

Catalyst Monitor

Heated Catalyst Monitor

EGR System Monitor

EVAP System Monitor

Secondary Air System Monitor

Air Conditioning (A/C) Monitor

The following provides a brief explanation of the function of eachMonitor:

Comprehensive Component Monitor (CCM) - This Monitorcontinuously checks all inputs and outputs from sensors, actu-

ators, switches and other devices that provide a signal to the comput-er. The Monitor checks for shorts, opens, out of range value, function-ality and “rationality.”

Rationality: Each input signal is compared against all otherinputs and against information in the computer’s memory tosee if it makes sense under the current operating conditions.Example: The signal from the throttle position sensor indi-cates the vehicle is in a wide-open throttle condition, but thevehicle is really at idle, and the idle condition is confirmed bythe signals from all other sensors. Based on the input data,the computer determines that the signal from the throttleposition sensor is not rational (does not make sense whencompared to the other inputs). In this case, the signal wouldfail the rationality test.

The CCM may be either a “One-Trip” or a “Two-Trip” Monitor, depend-ing on the component.

Fuel System Monitor - This Monitor uses a Fuel System Cor-rection program, called Fuel Trim, inside the on-board comput-

er. Fuel Trim is a set of positive and negative values that representadding or subtracting fuel from the engine.This program is used to cor-rect for a lean (too much air/not enough fuel) or rich (too much fuel/notenough air) air-fuel mixture. The program is designed to add or sub-tract fuel, as needed, up to a certain percent. If the correction neededis too large and exceeds the time and percent allowed by the program,a fault is indicated by the computer.

The Fuel System Monitor may be a “One-Trip” or “Two-Trip” Monitor,depending on the severity of the problem.

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Misfire Monitor - This Monitor continuously checks for enginemisfires. A misfire occurs when the air-fuel mixture in the cylin-

der does not ignite. The misfire Monitor uses changes in crankshaftspeed to sense an engine misfire. When a cylinder misfires, it nolonger contributes to the speed of the engine, and engine speeddecreases each time the affected cylinder(s) misfire. The misfireMonitor is designed to sense engine speed fluctuations and determinefrom which cylinder(s) the misfire is coming, as well as how bad themisfire is. There are three types of engine misfires, Types 1, 2, and 3.

- Type 1 and Type 3 misfires are two-trip monitor faults. If a fault issensed on the first trip, the computer temporarily saves the fault inits memory as a Pending Code. The MIL is not commanded on atthis time. If the fault is found again on the second trip, under similarconditions of engine speed, load and temperature, the computercommands the MIL “On,” and the code is saved in its long term mem-ory.

- Type 2 misfires are the most severe type of misfire. When a Type 2misfire is sensed on the first trip, the computer commands the MILto light when the misfire is sensed. If the computer determines thata Type 2 misfire is severe , and may cause catalytic converter dam-age, it commands the MIL to “flash” once per second as soon as themisfire is sensed. When the misfire is no longer present, the MILreverts to steady “On” condition.

Catalyst Monitor - The catalytic converter is a device that isinstalled downstream of the exhaust manifold. It helps to oxidize

(burn) the unburned fuel (hydrocarbons) and partially burned fuel (car-bon monoxide) left over from the combustion process. To accomplishthis, heat and catalyst materials inside the converter react with theexhaust gases to burn the remaining fuel. Some materials inside thecatalytic converter also have the ability to store oxygen, and release itas needed to oxidize hydrocarbons and carbon monoxide. In theprocess, it reduces vehicle emissions by converting the pollutinggases into carbon dioxide and water.

The computer checks the efficiency of the catalytic converter by mon-itoring the oxygen sensors used by the system. One sensor is locatedbefore (upstream of) the converter; the other is located after (down-stream of) the converter. If the catalytic converter loses its ability tostore oxygen, the downstream sensor signal voltage becomes almostthe same as the upstream sensor signal. In this case, the monitor failsthe test.

The Catalyst Monitor is a “Two-Trip” Monitor. If a fault is found on thefirst trip, the computer temporarily saves the fault in its memory as aPending Code. The computer does not command the MIL on at thistime. If the fault is sensed again on the second trip, the computer com-mands the MIL “On” and saves the code in its long-term memory.

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Heated Catalyst Monitor - Operation of the “heated” catalyticconverter is similar to the catalytic converter. The main differ-

ence is that a heater is added to bring the catalytic converter to itsoperating temperature more quickly. This helps reduce emissions byreducing the converter’s down time when the engine is cold. TheHeated Catalyst Monitor performs the same diagnostic tests as thecatalyst Monitor, and also tests the catalytic converter’s heater forproper operation. This Monitor is also a “Two-Trip” Monitor.

Exhaust Gas Recirculation (EGR) Monitor - The ExhaustGas Recirculation (EGR) system helps reduce the formation of

Oxides of Nitrogen during combustion. Temperatures above 2500°Fcause nitrogen and oxygen to combine and form Oxides of Nitrogen inthe combustion chamber. To reduce the formation of Oxides ofNitrogen, combustion temperatures must be kept below 2500°F. TheEGR system recirculates small amounts of exhaust gas back into theintake manifold, where it is mixed with the incoming air/fuel mixture.This reduces combustion temperatures by up to 500°F. The computerdetermines when, for how long, and how much exhaust gas is recircu-lated back to the intake manifold.The EGR Monitor performs EGR sys-tem function tests at preset times during vehicle operation.

The EGR Monitor is a “Two-Trip” Monitor. If a fault is found on the firsttrip, the computer temporarily saves the fault in its memory as aPending Code. The computer does not command the MIL on at thistime. If the fault is sensed again on the second trip, the computer com-mands the MIL “On,” and saves the code in its long-term memory.

Evaporative System (EVAP) Monitor - OBD 2 vehicles areequipped with a fuel Evaporative system (EVAP) that helps pre-

vent fuel vapors from evaporating into the air. The EVAP system car-ries fumes from the fuel tank to the engine where they are burned dur-ing combustion. The EVAP system may consist of a charcoal canister,fuel tank cap, purge solenoid, vent solenoid, flow monitor, leak detec-tor and connecting tubes, lines and hoses.

Fumes are carried from the fuel tank to the charcoal canister by hosesor tubes. The fumes are stored in the charcoal canister. The computercontrols the flow of fuel vapors from the charcoal canister to the enginevia a purge solenoid. The computer energizes or de-energizes thepurge solenoid (depending on solenoid design). The purge solenoidopens a valve to allow engine vacuum to draw the fuel vapors from thecanister into the engine where the vapors are burned. The EVAPMonitor checks for proper fuel vapor flow to the engine, and pressur-izes the system to test for leaks. The computer runs this Monitor onceper trip.

The EVAP Monitor is a “Two-Trip” Monitor. If a fault is found on the firsttrip, the computer temporarily saves the fault in its memory as aPending Code. The computer does not command the MIL on at thistime. If the fault is sensed again on the second trip, the PCM com-mands the MIL “On,” and saves the code in its long-term memory.

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Air Conditioning (A/C) Monitor - The A/C Monitor sensesleaks in air conditioning systems that utilize R-12 refrigerant.

Vehicle manufacturers have been given two options:

1. Use R-12 refrigerant in their A/C systems, and integrate an A/CMonitor in the OBD 2 systems of these vehicles to detect for refrig-erant leaks; or

2. Use R-134 refrigerant instead of R12. The A/C Monitor is notrequired on these vehicles.

To date, all vehicle manufacturers have opted to use R-134 in their A/Csystems. As a result, this Monitor has not yet been implemented.

Oxygen Sensor Heater Monitor - The Oxygen Sensor HeaterMonitor tests the operation of the oxygen sensor’s heater.There

are two modes of operation on a computer-controlled vehicle: “open-loop” and “closed-loop.” The vehicle operates in open-loop when theengine is cold, before it reaches normal operating temperature. Thevehicle also goes to open-loop mode at other times, such as heavyload and full throttle conditions. When the vehicle is running in open-loop, the oxygen sensor signal is ignored by the computer for air/fuelmixture corrections. Engine efficiency during open-loop operation isvery low, and results in the production of more vehicle emissions.

Closed-loop operation is the best condition for both vehicle emissionsand vehicle operation. When the vehicle is operating in closed-loop,the computer uses the oxygen sensor signal for air/fuel mixture cor-rections.

In order for the computer to enter closed-loop operation, the oxygensensor must reach a temperature of at least 600°F. The oxygen sensorheater helps the oxygen sensor reach and maintain its minimum oper-ating temperature (600°F) more quickly, to bring the vehicle intoclosed-loop operation as soon as possible.

The Oxygen Sensor Heater Monitor is a “Two-Trip” Monitor. If a fault isfound on the first trip, the computer temporarily saves the fault in itsmemory as a Pending Code. The computer does not command theMIL on at this time. If the fault is sensed again on the second trip, thecomputer commands the MIL “On,” and saves the code in its long-termmemory.

Oxygen Sensor Monitor - The Oxygen Sensor monitors howmuch oxygen is in the vehicle’s exhaust. It generates a varying

voltage of up to one volt, based on how much oxygen is in the exhaustgas, and sends the signal to the computer. The computer uses this sig-nal to make corrections to the air/fuel mixture. If the exhaust gas hasa large amount of oxygen (a lean air/fuel mixture), the oxygen sensorgenerates a “low” voltage signal. If the exhaust gas has very little oxy-gen (a rich mixture condition), the oxygen sensor generates a “high”voltage signal. A 450mV signal indicates the most efficient, and leastpolluting, air/fuel ratio of 14.7 parts of air to one part of fuel.

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The oxygen sensor must reach a temperature of at least 600-650°F,and the engine must reach normal operating temperature, for thecomputer to enter into closed-loop operation. The oxygen sensor onlyfunctions when the computer is in closed-loop. A properly operatingoxygen sensor reacts quickly to any change in oxygen content in theexhaust stream. A faulty oxygen sensor reacts slowly, or its voltage sig-nal is weak or missing.

The oxygen sensor is a “Two-Trip” monitor. If a fault is found on the firsttrip, the computer temporarily saves the fault in its memory as aPending Code. The computer does not command the MIL on at thistime. If the fault is sensed again on the second trip, the computer com-mands the MIL “On,” and saves the code in its long-term memory.

Secondary Air System Monitor - When a cold engine is firststarted, it runs in open-loop mode. During open-loop operation,

the engine usually runs rich. A vehicle running rich wastes fuel andcreates increased emissions, such as carbon monoxide and somehydrocarbons. A Secondary Air System injects air into the exhauststream to aid catalytic converter operation:

1. It supplies the catalytic converter with the oxygen it needs to oxidizethe carbon monoxide and hydrocarbons left over from the combus-tion process during engine warm-up.

2. The extra oxygen injected into the exhaust stream also helps thecatalytic converter reach operating temperature more quickly dur-ing warm-up periods. The catalytic converter must heat to operat-ing temperature to work properly.

The Secondary Air System Monitor checks for component integrity andsystem operation, and tests for faults in the system.The computer runsthis Monitor once per trip.

The Secondary Air System Monitor is a “Two-Trip” monitor. If a fault isfound on the first trip, the computer temporarily saves this fault in itsmemory as a Pending Code. The computer does not command theMIL on at this time. If the fault is sensed again on the second trip, thecomputer commands the MIL “On,” and saves the code in its long-termmemory.

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OBD 2 Reference Table

The table below lists current OBD 2 Monitors, and indicates the fol-lowing for each Monitor:

A. Monitor Type (how often does the Monitor run; Continuous or Onceper trip)

B. Number of trips needed, with a fault present, to set a pending DTC

C. Number of consecutive trips needed, with a fault present, to com-mand the MIL “On” and store a DTC

D. Number of trips needed, with no faults present, to erase a PendingDTC

E. Number and type of trips or drive cycles needed, with no faultspresent, to turn off the MIL

F. Number of warm-up periods needed to erase the DTC from thecomputer’s memory after the MIL is turned off

Name ofMonitor A B C D E F

Comprehensive Continuous 1 2 1 3 40Component Monitor

Misfire Monitor Continuous 1 2 1 3 - similar 80(Type 1 and 3) conditions

Misfire Monitor Continuous 1 3 - similar 80(Type 2) conditions

Fuel System Continuous 1 1 or 2 1 3 - similar 80Monitor conditions

Catalytic Converter Once per 1 2 1 3 trips 40Monitor trip

Oxygen Sensor Once per 1 2 1 3 trips 40Monitor trip

Oxygen Sensor Once per 1 2 1 3 trips 40Heater Monitor trip

Exhaust Gas Once per1 2 1 3 trips 40Recirculation (EGR) trip

Monitor

Evaporative Once per1 2 1 3 trips 40Emissions Controls trip

Monitor

Secondary Air Once per1 2 1 3 trips 40System (AIR) trip

Monitor

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Preparation for TestingPRELIMINARY VEHICLE DIAGNOSIS WORKSHEET

PRELIMINARY VEHICLE DIAGNOSIS WORKSHEET

The purpose of this form is to help you gather preliminary information onyour vehicle before you retrieve codes. By having a complete account ofyour vehicle's current problem(s), you will be able to systematically pin-point the problem(s) by comparing your answers to the fault codes youretrieve.You can also provide this information to your mechanic to assistin diagnosis and help avoid costly and unnecessary repairs. It is impor-tant for you to complete this form to help you and/or your mechanic havea clear understanding of your vehicle's problems. An electronic versionof this Preliminary Vehicle Diagnosis Worksheet is available online atwww.canOBD2.com. You can complete the form online and print a copyto take to your mechanic.

NAME:

DATE:

VIN*:

YEAR:

MAKE:

MODEL:

ENGINE SIZE:

VEHICLE MILEAGE:

*VIN: Vehicle Identification Number, found at the base of the windshieldon a metallic plate, or at the driver door latch area (consult your vehicleowner's manual for location).

TRANSMISSION:

❑ Automatic❑ Manual

Please check all applicable items in each category.

DESCRIBE THE PROBLEM:

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WHEN DID YOU FIRST NOTICE THE PROBLEM:

❑ Just Started❑ Started Last Week❑ Started Last Month❑ Other:

LIST ANY REPAIRS DONE IN THE PAST SIX MONTHS:

PROBLEMS STARTING

ENGINE QUITS OR STALLS

IDLING CONDITIONS

RUNNING CONDITIONS

❑ No symptoms❑ Will not crank

❑ Cranks, but will not start❑ Starts, but takes a long time

❑ No symptoms❑ Right after starting❑ When shifting into gear❑ During steady-speed driving

❑ Right after vehicle comes to a stop❑ While idling❑ During acceleration❑ When parking

❑ No symptoms❑ Is too slow at all times❑ Is too fast

❑ Is sometimes too fast or too slow❑ Is rough or uneven❑ Fluctuates up and down

❑ No symptoms❑ Runs rough❑ Lacks power❑ Bucks and jerks❑ Poor fuel economy❑ Hesitates or stumbles on

accelerations

❑ Backfires❑ Misfires or cuts out❑ Engine knocks, pings or rattles❑ Surges❑ Dieseling or run-on

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AUTOMATIC TRANSMISSION PROBLEMS (if applicable)

PROBLEM OCCURS

❑ Morning ❑ Afternoon ❑ Anytime

ENGINE TEMPERATURE WHEN PROBLEM OCCURS

❑ Cold ❑ Warm ❑ Hot

DRIVING CONDITIONS WHEN PROBLEM OCCURS

DRIVING HABITS

GASOLINE USED

WEATHER CONDITIONS WHEN PROBLEM OCCURS

CHECK ENGINE LIGHT / DASH WARNING LIGHT

❑ Sometimes ON ❑ Always ON ❑ Never ON

PECULIAR SMELLS

STRANGE NOISES

❑ Short - less than 2 miles❑ 2 - 10 miles❑ Long - more than 10 miles❑ Stop and go❑ While turning❑ While braking❑ At gear engagement❑ With A/C operating

❑ With headlights on❑ During acceleration❑ Mostly driving downhill❑ Mostly driving uphill❑ Mostly driving level❑ Mostly driving curvy roads❑ Mostly driving rough roads

❑ Mostly city driving❑ Highway❑ Park vehicle inside❑ Park vehicle outside

❑ Drive less than 10 miles per day❑ Drive 10 to 50 miles per day❑ Drive more than 50 miles per day

❑ 87 Octane❑ 89 Octane

❑ 91 Octane❑ More than 91 Octane

❑ 32 - 55° F (0 - 13° C)❑ Below freezing (32° F / 0° C)

❑ Above 55° F (13° C)

❑ "Hot"❑ Sulfur ("rotten egg")❑ Burning rubber

❑ Gasoline❑ Burning oil❑ Electrical

❑ Rattle❑ Knock

❑ Squeak❑ Other

❑ No symptoms❑ Shifts too early or too late❑ Changes gear incorrectly

❑ Vehicle does not move when in gear

❑ Jerks or bucks

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Preparation for TestingBEFORE YOU BEGIN

BEFORE YOU BEGIN

The CAN OBD2 Code Readeraids in monitoring electronic-and emissions-related faults inyour vehicle and retrievingfault codes related to malfunc-tions in these systems.Mechanical problems such aslow oil level or damagedhoses, wiring or electrical connectors can cause poor engine perform-ance and may also cause a fault code to set. Fix any known mechan-ical problems before performing any test. See your vehicle’s servicemanual or a mechanic for more information.

Check the following areas before starting any test:

■ Check the engine oil, power steering fluid, transmission fluid (ifapplicable), engine coolant and other fluids for proper levels. Top offlow fluid levels if needed.

■ Make sure the air filter is clean and in good condition. Make sure allair filter ducts are properly connected. Check the air filter ducts forholes, rips or cracks.

■ Make sure all engine belts are in good condition. Check for cracked,torn, brittle, loose or missing belts.

■ Make sure mechanical linkages to engine sensors (throttle,gearshift position, transmission, etc.) are secure and properly con-nected. See your vehicle’s service manual for locations.

■ Check all rubber hoses (radiator) and steel hoses (vacuum/fuel) forleaks, cracks, blockage or other damage. Make sure all hoses arerouted and connected properly.

■ Make sure all spark plugs are clean and in good condition. Checkfor damaged, loose, disconnected or missing spark plug wires.

■ Make sure the battery terminals are clean and tight. Check for cor-rosion or broken connections. Check for proper battery and charg-ing system voltages.

■ Check all electrical wiring and harnesses for proper connection.Make sure wire insulation is in good condition, and there are nobare wires.

■ Make sure the engine is mechanically sound. If needed, perform acompression check, engine vacuum check, timing check (if applica-ble), etc.

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Preparation for TestingVEHICLE SERVICE MANUALS

VEHICLE SERVICE MANUALS

Always refer to the manufacturer’s service manual for your vehiclebefore performing any test or repair procedures. Contact your local cardealership, auto parts store or bookstore for availability of these man-uals. The following companies publish valuable repair manuals:

■ Haynes Publications861 Lawrence DriveNewbury Park, California 91320Phone: 800-442-9637

■ Mitchell International14145 Danielson StreetPoway, California 92064Phone: 888-724-6742

■ Motor Publications5600 Crooks Road, Suite 200Troy, Michigan 48098Phone: 800-426-6867

FACTORY SOURCES

Ford, GM, Chrysler, Honda, Isuzu, Hyundai and Subaru ServiceManuals

■ Helm Inc.14310 Hamilton AvenueHighland Park, Michigan 48203Phone: 800-782-4356

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Using the Code ReaderCODE RETRIEVAL PROCEDURE

CODE RETRIEVAL PROCEDURE

Never replace a part based only on the DTC definition.Each DTC has a set of testing procedures, instructionsand flow charts that must be followed to confirm the loca-tion of the problem. This information is found in the vehicle'sservice manual. Always refer to the vehicle's service manualfor detailed testing instructions.

Check your vehicle thoroughly before performingany test. See Before You Begin on page 33 fordetails.

ALWAYS observe safety precautions whenever working on avehicle. See Safety Precautions on page 3 for more infor-mation.

1. Turn the ignition off.

2. Locate the vehicle's 16-pin Data LinkConnector (DLC). See page 5 for con-nector location.

Some DLCs have a plastic coverthat must be removed before con-necting the Code Reader cableconnector.

If the Code Reader is ON, turn itOFF by pressing the POWER/LINK

button BEFORE connectingthe Code Reader to the DLC.

3. Connect the Code Reader cable connector to the vehicle’s DLC.The cable connector is keyed and will only fit one way.

■ If you have problems connecting the cable connector to the DLC,rotate the connector 180° and try again.

■ If you still have problems, check the DLC on the vehicle and onthe Code Reader. Refer to your vehicle’s service manual to prop-erly check the vehicle’s DLC.

4. When the Code Reader’s cable connec-tor is properly connected to the vehicle’sDLC, the unit automatically turns ON,and the LCD display shows instructionsfor linking to the vehicle’s on-board computer.

Retrieving and using Diagnostic Trouble Codes (DTCs) fortroubleshooting vehicle operation is only one part of an

overall diagnostic strategy.

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■ If the unit does not power on automatically when connected tothe vehicle’s DLC connector, it usually indicates there is nopower present at the vehicle’s DLC connector. Check your fusepanel and replace any burned-out fuses.

■ If replacing the fuse(s) does not correct the problem, consult yourvehicle’s repair manual to identify the proper computer (PCM) fuse/circuit, and perform any necessary repairs before proceeding.

5. Turn the ignition on. DO NOT start the engine.

6. Press and release the Code Reader’s POWER/LINK button.

■ The Code Reader will automaticallystart a check of the vehicle’s comput-er to determine which type of com-munication protocol it is using. Whenthe Code Reader identifies the com-puter’s communication protocol, acommunication link is established.The protocol type used by the vehi-cle’s computer is shown on the LCDdisplay.

A PROTOCOL is a set of rules and procedures for regu-lating data transmission between computers, and betweentesting equipment and computers. As of this writing, fivedifferent types of protocols (ISO 9141, Keyword 2000,J1850 PWM, J1850 VPW and CAN) are in use by vehiclemanufacturers. The Code Reader automatically identifiesthe protocol type and establishes a communication linkwith the vehicle’s computer.

7. After approximately 4~5 seconds, the Code Reader will retrieveand display any Diagnostic Trouble Codes, Monitor Status andFreeze Frame Data retrieved from the vehicle’s computer memory.

■ If the Code Reader fails to link to thevehicle’s computer a “Linking Failed”message shows on the CodeReader’s LCD display.

- Verify the connection at the DLC:and verify the ignition is ON.

- Turn the ignition OFF, wait 5 seconds, then turn back ON toreset the computer.

- Ensure your vehicle is OBD2 compliant. See VehiclesCovered on page 5 for vehicle compliance verification infor-mation.

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■ The Code Reader will automaticallyre-link to the vehicle’s computer every15 seconds to refresh the data beingretrieved. When data is being re-freshed, the message “One momentAuto – link in progress” is shown on theLCD display. This action repeats aslong as the Code Reader is commu-nicating with the vehicle’s computer.

■ The Code Reader will display a codeonly if codes are present in the vehi-cle’s computer memory. If no codesare present, a “No DTC’s are present-ly stored in the vehicle’s computer” isdisplayed.

■ The Code Reader is capable of retrieving and storing up to 32codes in memory, for immediate or later viewing.

8. To read the display:

Refer to Display Functions on page 25 for a descriptionof LCD display elements.

■ A visible icon indicates that the Code Reader is being pow-ered through the vehicle’s DLC connector.

■ A visible icon indicates that the Code Reader is linked to(communicating with) the vehicle’s computer.

■ The I/M Monitor Status icons indicate the type and number ofMonitors the vehicle supports, and provides indications of thecurrent status of the vehicle’s Monitors. A solid Monitor icon indi-cates the associated Monitor has run and completed its testing.A blinking Monitor icon indicates the associated Monitor hasnot run and completed its testing.

■ The upper right hand corner of thedisplay shows the number of the codecurrently being displayed, the totalnumber of codes retrieved, the typeof code (G = Generic; E = Enhancedor Manufacturer specific), andwhether or not the displayed codecommanded the MIL on. If the codebeing displayed is a PENDING code, the PENDING icon isshown.

■ The Diagnostic Trouble Code (DTC) and related code definitionare shown in the lower section of the LCD display.

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In the case of long code definitions, or when viewingFreeze Frame data, a small arrow is shown in theupper/lower right-hand corner of the code display areato indicate the presence of additional information. Usethe and buttons, as necessary, to view the addi-tional information.

9. Read and interpret Diagnostic Trouble Codes/system conditionusing the LCD display and the green, yellow and red LEDs.

The green, yellow and red LEDs are used (with the LCDdisplay) as visual aids to make it easier to determineengine system conditions.

■ Green LED – Indicates that allengine systems are “OK” and operat-ing normally. All monitors supportedby the vehicle have run and per-formed their diagnostic testing, andno trouble codes are present. A zerowill show on the Code Reader’s LCDdisplay, and all Monitor icons will besolid.

■ Yellow LED – Indicates one of the following conditions:

A. A PENDING CODE IS PRESENT – Ifthe yellow LED is illuminated, it mayindicate a Pending code is present.Check the Code Reader’s LCD dis-play for confirmation. A Pending codeis confirmed by the presence of anumeric code and the word PEND-ING on the Code Reader’s LCD dis-play.

B. MONITOR NOT RUN STATUS – If theCode Reader’s LCD display shows azero (indicating there are no DTC’spresent in the vehicle’s computermemory), but the yellow LED is illu-minated, it may be an indication thatsome of the Monitors supported bythe vehicle have not yet run and com-pleted their diagnostic testing. Checkthe Code Reader’s LCD display for confirmation. All Monitoricons that are blinking have not yet run and completed theirdiagnostic testing; all Monitor icons that are solid have run andcompleted their diagnostic testing.

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■ Red LED – Indicates there is a prob-lem with one or more of the vehicle’ssystems. The red LED is also used toindicate that DTC(s) are present (dis-played on the Code Reader’s screen).In this case, the Multifunction Indicator(Check Engine) lamp on the vehicle’sinstrument panel will be illuminated.

On some vehicle models, the computer will store non-emission related DTCs.These DTCs will not command theMIL on since they are not emission related. If the CodeReader retrieves one of these types of codes, the MIL willnot be commanded on, and the Yellow LED on the CodeReader will be illuminated.

■ DTC’s that start with “P0”, “P2” and some “P3” are consideredGeneric (Universal). All Generic DTC definitions are the same onall OBD2 equipped vehicles. The Code Reader automatically dis-plays the code definitions for Generic DTC’s.

■ DTC’s that start with “P1” and some“P3” are Enhanced (Manufacturer spe-cific) codes and their code definitionsvary with each vehicle manufacturer.When an Enhanced (Manufacturerspecific) DTC is retrieved, the LCD dis-play shows a list of vehicle manufactur-ers. Use the UP and DOWNbuttons, as necessary, to highlight the appropriate manufacturer,then press the ENTER/FF button to display the correct codedefinition for your vehicle.

If the manufacturer for your vehicle is not listed, use theUP and DOWN buttons, as necessary, to selectOther manufacturer and press the ENTER/FF but-ton for additional DTC information.

If the Manufacturer Specificdefinition for the currently dis-played code is not available, anadvisory message shows onthe Code Reader’s LCD dis-play.

10. If more than one code was retrieved press the DTC SCROLLbutton, as necessary, to display additional codes one at a time.

■ Whenever the Scroll function is used to view additional codes,the Code Reader’s communication link with the vehicle’s com-puter disconnects. To re-establish communication, press theLINK button again.

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11. Freeze Frame Data (if available) can be viewed at any time (exceptMENU mode) by pressing the ENTER/FF button.

■ In OBD2 systems, when an emis-sions-related engine malfunctionoccurs that causes a DTC to set, arecord or snapshot of engine condi-tions at the time that the malfunctionoccurred is also saved in the vehi-cle’s computer memory. The recordsaved is called Freeze Frame data.Saved engine conditions include, but are not limited to: enginespeed, open or closed loop operation, fuel system commands,coolant temperature, calculated load value, fuel pressure, vehi-cle speed, air flow rate, and intake manifold pressure.

If more than one malfunction is present that causes morethan one DTC to be set, only the code with the highest pri-ority will contain Freeze Frame data. The code designated“01” on the Code Reader display is referred to as the PRIORITY code, and Freeze Frame data always refers tothis code. The priority code is also the one that has com-manded the MIL on.

If Freeze Frame data is notavailable for the code shownon the LCD display when theENTER/FF button ispressed, an advisory messageshows on the LCD display.Press the DTC SCROLLbutton to return to the previouscode display.

Retrieved information can be uploaded to a PersonalComputer (PC) with the use of an optional “PC Link Kit.”For more information, visit us on the Web atwww.canOBD2.com or call our service department. SeeService Procedures on page 51 for more information.

12. Determine engine system(s) condition by viewing the CodeReader’s LCD display for any retrieved Diagnostic Trouble Codes,code definitions, Freeze Frame data and interpreting the green,yellow and red LEDs.

■ If DTC’s were retrieved and you are going to perform the repairsyourself, proceed by consulting the Vehicle’s Service RepairManual for testing instructions, testing procedures, and flowcharts related to retrieved code(s).

■ If you plan to take the vehicle to a professional to have it serv-iced, complete the Preliminary Vehicle Diagnosis Worksheeton page 30 and take it together with the retrieved codes, freezeframe data and LED information to aid in the troubleshootingprocedure.

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■ To prolong battery life, the Code Reader automatically shuts“Off” approximately three minutes after it is disconnected fromthe vehicle.The DTCs retrieved, Monitor Status and Freeze Framedata (if any) will remain in the Code Reader’s memory, and maybe viewed at any time by turning the unit “On”. If the CodeReader’s batteries are removed, or if the Code Reader is re-linked to a vehicle to retrieve codes/data, any prior codes/data inits memory are automatically cleared.

ERASING DIAGNOSTIC TROUBLE CODES (DTCs)

When the Code Reader’s ERASE function is used to eraseDTCs from the vehicle's on-board computer, "FreezeFrame" data and manufacturer-specific enhanced dataare also erased.

If you plan to take the vehicle to a Service Center for repair, DO NOTerase the codes from the vehicle's computer. If the codes are erased,valuable information that might help the technician troubleshoot theproblem will also be erased.

Erase DTCs from the computer's memory as follows:

When DTCs are erased from the vehicle's computer memo-ry, the I/M Readiness Monitor Status program resets the sta-tus of all Monitors to a not run "flashing" condition. To set allof the Monitors to a DONE status, an OBD 2 Drive Cyclemust be performed. Refer to your vehicle's service manual forinformation on how to perform an OBD 2 Drive Cycle for thevehicle under test.

The Code Reader must be con-nected to the vehicle’s DLC toerase the codes from the comput-er’s memory. If you press theERASE button when theCode Reader is not connected tothe vehicle’s DLC, the eraseinstruction screen displays.

1. If not connected already, connect theCode Reader to the vehicle's DLC, andturn the ignition "On.” (If the Code Readeris already connected and linked to thevehicle's computer, proceed directly tostep 4. If not, continue to step 2.)

2. Turn the ignition on. DO NOT start theengine. Press and release thePOWER/LINK button to establishcommunication with the vehicle's com-puter.

Using the Code ReaderERASING DIAGNOSTIC TROUBLE CODES (DTCs)

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Using the Code ReaderI/M READINESS TESTING

3. Press and release the ERASE but-ton. A confirmation message shows onthe LCD display.

- If you are sure you want to proceedpress the ERASE button again toerase DTCs from the vehicle’s com-puter.

- If you do not want to continue with the erase process, press thePOWER/LINK button to exit the erase mode.

4. If you chose to erase DTCs, a progressscreen displays while the erase functionis in progress.

■ If the erase was successful, a confir-mation message shows on the LCDdisplay. Press the POWER/LINK

button to return to the DTCscreen.

■ If the erase was not successful, anadvisory message shows on theLCD display. Verify that the CodeReader is properly connected to thevehicle’s DLC and that the ignition ison, then repeat steps 2 and 3, above.

Erasing DTCs does not fix the problem(s) that caused thecode(s) to be set. If proper repairs to correct the problem thatcaused the code(s) to be set are not made, the code(s) willappear again (and the check engine light will illuminate) assoon as the vehicle is driven long enough for its Monitors tocomplete their testing.

I/M READINESS TESTING

I/M is an Inspection and Maintenance program legislated by theGovernment to meet federal clean-air standards.

The program requires that a vehicle be taken periodically to anEmissions Station for an "Emissions Test" or "Smog Check,” where theemissions-related components and systems are inspected and testedfor proper operation. Emissions Tests are generally performed once ayear, or once every two years.

On OBD 2 systems, the I/M program is enhanced by requiring vehicles tomeet stricter test standards. One of the tests instituted by the FederalGovernment is called I/M 240. On I/M 240, the vehicle under test is driv-en under different speeds and load conditions on a dynamometer for 240seconds, while the vehicle's emissions are measured.

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Emissions tests vary depending on the geographic or region-al area in which the vehicle is registered. If the vehicle is reg-istered in a highly urbanized area, the I/M 240 is probably thetype of test required. If the vehicle is registered in a rural area,the stricter “dynamometer type” test may not be required.

I/M Readiness Monitors

I/M Readiness shows whether the various emissions-related systemson the vehicle are operating properly and are ready for Inspection andMaintenance testing.

State and Federal Governments enacted Regulations, Procedures andEmission Standards to ensure that all emissions-related componentsand systems are continuously or periodically monitored, tested anddiagnosed whenever the vehicle is in operation. It also requires vehi-cle manufacturers to automatically detect and report any problems orfaults that may increase the vehicle's emissions to an unacceptable level.

The vehicle's emissions control system consists of several compo-nents or sub-systems (Oxygen Sensor, Catalytic Converter, EGR, FuelSystem, etc.) that aid in reducing vehicle emissions.

To have an efficient Vehicle Emission Control System, all the emis-sions-related components and systems must work correctly wheneverthe vehicle is in operation.

To comply with State and Federal Government regulations, vehiclemanufacturers designed a series of special computer programs called"Monitors" that are programmed into the vehicle's computer. Each ofthese Monitors is specifically designed to run tests and diagnostics ona specific emissions-related component or system (Oxygen Sensor,Catalytic Converter, EGR Valve, Fuel System, etc.) to ensure theirproper operation. Currently, there are a maximum of eleven Monitorsavailable for use.

Each Monitor has a specific function to testand diagnose only its designated emissions-related component or system. The names of theMonitors (Oxygen Sensor Monitor, CatalystMonitor, EGR Monitor, Misfire Monitor, etc.)describe which component or system each Monitoris designed to test and diagnose.


To learn more about Emissions Inspection and Maintenance(I/M) Readiness Monitors, see OBD 2 MONITORS on page 23.

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Emissions Inspection and Maintenance (I/M) Readiness

Monitor Status Inf ormation

I/M Readiness Monitor Status shows which of the vehicle's Monitorshave run and completed their diagnosis and testing, and which oneshave not yet run and completed testing and diagnosis of their desig-nated sections of the vehicle's emissions system.

■ If a Monitor was able to meet all the conditions required to enable itto perform the self-diagnosis and testing of its assigned engine sys-tem, it means the monitor "HAS RUN.”

■ If a Monitor has not yet met all the conditions required for it to per-form the self-diagnosis and testing of its assigned engine system; itmeans the Monitor "HAS NOT RUN.”

The Monitor Run/Not Run status does not show whetheror not a problem exists in a system. Monitor status onlyindicates whether a particular Monitor has or has not runand performed the self-diagnosis and testing of its asso-ciated system.

Performing I/M Readiness Quic k Chec k

When a vehicle first comes from the factory, all Monitors indi-cate a “HAVE RUN” status. This indicates that all Monitorshave run and completed their diagnostic testing. The “HAVERUN” status remains in the computer's memory, unless theDiagnostic Trouble Codes are erased or the vehicle's com-puter memory is cleared.

The Code Reader allows you to retrieve Monitor/System Status Infor-mation to help you determine if the vehicle is ready for an EmissionsTest (Smog Check). In addition to retrieving Diagnostic Trouble Codes,the Code Reader also retrieves Monitor Run/Not Run status. This infor-mation is very important since different areas of the state/country havedifferent emissions laws and regulations concerning Monitor Run/NotRun status.

Before an Emissions Test (Smog Check) can be performed, your vehi-cle must meet certain rules, requirements and procedures legislatedby the Federal and state (country) governments where you live.

1. In most areas, one of the requirements that must be met before avehicle is allowed to be Emissions Tested (Smog Checked) is thatthe vehicle does not have any Diagnostic Trouble Codes present(with the exception of PENDING Diagnostic Trouble Codes).

2. In addition to the requirement that no Diagnostic Trouble Codes bepresent, some areas also require that all the Monitors that a partic-ular vehicle supports indicate a "Has Run" status condition beforean Emissions Check may be performed.


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3. Other areas may only require that some (but not all) Monitors indi-cate a "Has Run" status before an Emissions Test (Smog Check)may be performed.

Monitors with a "Has Run" status indicate that all therequired conditions they needed to perform diagnosisand testing of their assigned engine area (system) havebeen met, and all diagnostic testing has completed suc-cessfully.

Monitors with a "Has Not Run" status have not yet metthe conditions they need to perform diagnosis and test-ing of their assigned engine area (system), and have notbeen able to perform diagnostic testing on that system.

The green, yellow and red LEDs provide a quick way to help you deter-mine if a vehicle is ready for an Emissions Test (Smog Check). Followthe instructions below to perform the Quick Check.

Perform the Code Retrieval Procedure as described on page 35,then interpret the LED indications as follows:

Interpreting I/M Readiness Test Results

1. GREEN LED - Indicates that all enginesystems are "OK" and operating nor-mally (all Monitors supported by thevehicle have run and performed theirself-diagnostic testing). The vehicle isready for an Emissions Test (SmogCheck), and there is a good possibilitythat it can be certified.

2. YELLOW LED - Determine from the Code Retrieval Procedure(page 35) which of the two possible conditions is causing the yellowLED to light.

■ If a "PENDING" Diagnostic TroubleCode is causing the yellow LED tolight, it is possible that the vehicle willbe allowed to be tested for emissionsand certified. Currently, most areas(states / countries) will allow anEmissions Test (Smog Check) to beperformed if the only code in the vehi-cle's computer is a "PENDING"Diagnostic Trouble Code.


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■ If the illumination of the Yellow LED isbeing caused by monitors that “havenot run” their diagnostic testing, thenthe issue of the vehicle being readyfor an Emissions Test (Smog Check)depends on the emissions regula-tions and laws of your local area.

- Some areas require that allMonitors indicate a "Has Run" status before they allow anEmissions Test (Smog Check) to be performed. Other areasonly require that some, but not all, Monitors have run theirself-diagnostic testing before an Emissions Test (SmogCheck) may be performed.

From the code retrieval procedure, determine the status ofeach Monitor (a solid Monitor icon shows Monitor "Has Run"status, a flashing Monitor icon indicates "Has Not Run" sta-tus). Take this information to an emissions professional todetermine (based on your test results) if your vehicle is readyfor an Emissions Test (Smog Check).

3. RED LED - Indicates there is a problemwith one or more of the vehicle's sys-tems. A vehicle displaying a red LED isdefinitely not ready for an EmissionsTest (Smog Check). The red LED is alsoan indication that there are DiagnosticTrouble Code(s) present (displayed onthe Code Reader's screen). TheMultifunction Indicator (Check Engine)Lamp on the vehicle's instrument panel will light steady. The prob-lem that is causing the red LED to light must be repaired before anEmissions Test (Smog Check) can be performed. It is also suggest-ed that the vehicle be inspected/repaired before driving the vehiclefurther.

If the Red LED was obtained, there is a definite problem present inthe system(s). In these cases, you have the following options.

■ Repair the vehicle yourself. If you are going to perform therepairs yourself, proceed by reading the vehicle service manualand following all its procedures and recommendations.

■ Take the vehicle to a professional to have it serviced. The prob-lem(s) causing the red LED to light must be repaired before thevehicle is ready for an Emissions Test (Smog Check).


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On some vehicle models, the computer will store non-emission related DTCs. These DTCs will not command theMIL on since they are not emission related. If the CodeReader retrieves one of these types of codes, the MIL will notbe commanded on, and the Yellow LED on the Code Readerwill be iluminated. In most cases, these types of codes willnot prevent the Emissions Test from being performed.

Using the I/M Readiness Monitor Status to Confirm a Repair

The I/M Readiness Monitor Status function can be used (after repair ofa fault has been performed) to confirm that the repair has been per-formed correctly, and/or to check for Monitor Run Status. Use the fol-lowing procedure to determine I/M Readiness Monitor Status:

1. Using retrieved Diagnostic Trouble Codes (DTCs) and code defini-tions as a guide, and following manufacturer's repair procedures,repair the fault or faults as instructed.

2. After the fault or faults have been repaired, connect the CodeReader to the vehicle's DLC and erase the code or codes from thevehicle's computer memory.

■ See page 41 for procedures to erase DTCs from the vehicle's on-board computer.

■ Write the codes down on a piece of paper for reference beforeerasing.

3. After the erase procedure is performed, most of the Monitor iconson the Code Reader’s LCD display will be flashing. Leave the CodeReader connected to the vehicle, and perform a Trip Drive Cycle foreach "flashing" Monitor:

Misfire, Fuel and Comprehensive Component Monitors runcontinuously and their icons will always be on solid, evenafter the erase function is performed.

■ Each DTC is associated with a specific Monitor. Consult the vehi-cle's service manual to identify the Monitor (or Monitors) associ-ated with the faults that were repaired. Follow the manufacturer'sprocedures to perform a Trip Drive Cycle for the appropriateMonitors.

■ While observing the Monitor icons on the Code Reader’s LCDdisplay, perform a Trip Drive Cycle for the appropriate Monitor orMonitors.

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If the vehicle needs to be driven in order to perform a TripDrive Cycle, ALWAYS have a second person help you.One person should drive the vehicle while the other per-son observes the Monitor icons on the Code Reader forMonitor RUN status. Trying to drive and observe theCode Reader at the same time is dangerous, and couldcause a serious traffic accident.

4. When a Monitor's Trip Drive Cycle is performed properly, theMonitor icon on the Code Reader’s LCD display changes from"flashing" to "solid,” indicating that the Monitor has run and finishedits diagnostic testing.

■ If, after the Monitor has run, the MIL on the vehicle's dash is notlit, and no stored or pending codes associated with that particu-lar Monitor are present in the vehicle's computer, the repair wassuccessful.

■ If, after the Monitor has run, the MIL on the vehicle's dash lightsand/or a DTC associated with that Monitor is present in the vehi-cle's computer, the repair was unsuccessful. Refer to the vehi-cle's service manual and recheck repair procedures.

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GlossaryGLOSSARY OF TERMS AND ABBREVIATIONS

INTRODUCTION

This Glossary contains definitions for abbreviations and terms youmay find in this manual or in your vehicle service manual.

GLOSSARY OF TERMS AND ABBREVIATIONS

CARB – California Air Resources Board

CCM – Central Control Module

Computer Control System – An electronic control system, consistingof an on-board computer and related sensors, switches and actuators,used to ensure peak performance and fuel efficiency while reducingpollutants in the vehicle’s emissions.

DIY – Do-It-Yourself

DLC – Data Link Connector

Drive Cycle – An extended set of driving procedures that takes intoconsideration the various types of driving conditions encountered inreal life.

Driving Condition – A specific environmental or operation conditionunder which a vehicle is operated; such as starting the vehicle whencold, driving at steady speed (cruising), accelerating, etc.

DTC(s) – Diagnostic Trouble Code(s)

EGR – Exhaust Gas Recirculation

EPA – Environmental Protection Agency

EVAP – Evaporative Emissions System

Fault Code – See DTCs

Freeze Frame – A digital representation of engine and/or emissionssystem conditions present when a fault code was recorded.

FTP – Fuel Tank Pressure

Generic Code – A DTC that applies to all OBD 2 compliant vehicles.

I/M Readiness – An indication of whether or not a vehicle’s emissions-related system are operating properly and are ready for Inspection andMaintenance testing.

I/M Test / Emissions Test / Smog Check – A functional test of a vehi-cle to determine if tailpipe emissions are within Federal/State/Localrequirements.

LCD – Liquid Crystal Display

LED – Light Emitting Diode

LTFT – Long Term Fuel Trim, is a program in the vehicle’s computerdesigned to add or subtract fuel from the vehicle to compensate foroperating conditions that vary from the ideal A/F ratio (long term).

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GlossaryGLOSSARY OF TERMS AND ABBREVIATIONS

Manufacturer Specific Code – A DTC that applies only to OBD 2compliant vehicles made by a specific manufacturer.

MIL – Malfunction Indicator Lamp (also referred to as “Check Engine”light

OBD 1 – On-Board Diagnostics Version 1 (also referred to as “OBD I”)

OBD 2 – On-Board Diagnostics Version 2 (also referred to as “OBD II”)

On-Board Computer – The central processing unit in the vehicle’scomputer control system.

PCM – Powertrain Control Module

Pending Code – A code recorded on the “first trip” for a “two-trip”code. If the fault that caused the code to be set is not detected on thesecond trip, the code is automatically erased.

STFT – Short Term Fuel Trim, is a program in the vehicle’s computerdesigned to add or subtract fuel from the vehicle to compensate foroperating conditions that vary from the ideal A/F ratio.The vehicle usesthis program to make minor fuel adjustments (fine tune) on a short-term basis.

Trip Drive Cycle – Vehicle operation that provides the necessary driv-ing condition to enable a vehicle Monitor to run and complete its diag-nostic testing.

VECI – Vehicle Emission Control Information Decal

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Warranty and Servicing

LIMITED ONE YEAR WARRANTY

The Manufacturer warrants to the original purchaser that this unit isfree of defects in materials and workmanship under normal use andmaintenance for a period of one (1) year from the date of original pur-chase.

If the unit fails within the one (1) year period, it will be repaired orreplaced, at the Manufacturer’s option, at no charge, when returnedprepaid to the Service Center with Proof of Purchase. The salesreceipt may be used for this purpose. All replacement parts, whethernew or re-manufactured, assume as their warranty period only theremaining time of this warranty.

This warranty does not apply to damage caused by improper use, acci-dent, abuse, improper voltage, service, fire, flood, lightning, or otheracts of God, or if the product was altered or repaired by anyone otherthan the Manufacturer’s Service Center.

The Manufacturer, under no circumstances shall be liable for any con-sequential damages for breach of any written warranty of this unit. Thiswarranty gives you specific legal rights, and you may also have rightswhich vary from state to state.This manual is copyrighted with all rightsreserved. No portion of this document may be copied or reproduced byany means without the express written permission of the Manufacturer.THIS WARRANTY IS NOT TRANSFERABLE. For service, send viaU.P.S. (if possible) prepaid to Manufacturer. Allow 3-4 weeks for service/repair.

SERVICE PROCEDURES

If you have any questions, please contact your local store, distributoror the Service Center.

USA & Canada:

(800) 544-4124 (9:00-4:00, Monday-Friday PST)

All others: (714) 241-6802 (9:00-4:00, Monday-Friday PST)

FAX: (714) 432-7910 (24 hr.)

For technical support and information on UPDATES and OPTIONALACCESSORIES, visit on the Web at www.CanOBD2.com or contact usthrough Fax: (714) 432-7511; Phone: 1-800-544-4124 or (714) 241-6805 (7AM-4PM Pacific Standard Time).

Notes

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Notes

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Innova Electronics Corp.17291 Mt. Herrmann StreetFountain Valley, CA 92708Printed in Taiwan

Instruction MRP #93-0036

PRODUCT DESIGN & COPYRIGHT

© 2004

®