05:05-02 · play or using a PC and the Scania Diagnos program. The latter makes fault diagnosis quicker. Opticruise requires that the vehicle be fitted with both EDC and ABS/TC, due

© Scania CV AB 1995-10

Opticruise

Description of operation and work description

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Contents

General Opticruise in brief ..............................................3

Introduction ........................................................4

Controls and operation .......................................6

Description of operation Gear changing ....................................................7

Opticruise controls the engine via EDC ............ 7

Gear changing sequence, description ................ 8

Engine brake program ....................................... 9

Starting gear, programming .............................. 9

Kick-down ..........................................................9

Auxiliary brake system ......................................9

EDC cruise control .......................................... 10

ABS/TC ............................................................10

Power take-offs ................................................10

Configuration, control unit .............................. 11

Power supply and fuses ................................... 11

Interaction with other systems ........................ 12

Opticruise, design .............................................14

Warning system ................................................16

Fault codes General .............................................................19Faults that do not generate fault codes ............ 19

Clarifications, new terms ................................ 20

List of fault codes ....................................... 19-52

Electrical system References to wiring diagrams ........................ 53Location of electrical components ............. 54-55

Control unit signals .................................... 56-59

Driving mode selector ......................................60

Test program .............................................. 61-71

Mechanical work General .............................................................73Instructions for repair and adjustment ....... 73-76

Exploded view drawings Components on gearbox ............................. 77-83


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General

General

Opticruise in briefOpticruise is a system which allows a normalmanual gearbox to shift automatically. Theclutch is retained but is used only when start-ing, stopping and shunting.

A control unit collects and processes data fromcontrols, sensors and adjacent systems such asEDC, ABS/TC and auxiliary brake (if fitted).

When it is time to change gear, the control unitactuates the solenoid valves, releasing com-pressed air to the air cylinders. These air cylin-ders then change to the required gear.

The control unit has an in-built warning sys-tem. Fault codes can either be read on the dis-play or using a PC and the Scania Diagnosprogram. The latter makes fault diagnosisquicker.

Opticruise requires that the vehicle be fittedwith both EDC and ABS/TC, due to the infor-mation exchange requirements between thesystems.

When changing gear, the engine speed is con-trolled so that the speeds of the gearbox inputshaft and output shaft correspond for the gearto be engaged. Gear changing is only thencompleted.

When necessary, the exhaust brake is used tomake changing up fast and smooth.

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General

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Scania Opticruise is an automatic gear changing system formanual gearboxes. Opticruise is constructed in more or lessthe same way as the Scania CAG system, the major differencebeing that the driver only needs to use the clutch pedal whenstarting, stopping and shunting.

The system is able to change gear automatically without theclutch because the engine is regulated to synchronous speedfor the gear that is to be engaged. This means that the elec-tronics adapt both engine speed and torque to exactly the lev-els required by the gearbox. This makes all gear changinggentle and precise, increasing the service life of the entirepowertrain.

Opticruise requires the engine to be equipped with EDC. Itwould not be possible, using a mechanical injection pump, tocontrol the engine with the speed and precision required forOpticruise to work smoothly. Opticruise also requires thevehicle to be equipped with ABS/TC in order to select thecorrect gear, even if the drive wheels lose grip on a slipperyroad surface.

Using Opticruise, the driver can choose to drive with manualor automatic gear selection. In manual gear selection drivingmode, the driver selects the gear and when it is changed(depending on road speed and/or engine speed). The controlunit decides whether it is possible to change gear without thedriver using the clutch. If this is the case, the gear is immedi-ately changed when the driver moves the driving mode selec-tor sideways. Otherwise, the driver has to depress the clutchpedal in order to change gear.

In automatic gear selection driving mode, the control unit cal-culates which gear is appropriate and carries out this shiftwhen the calculation is complete. In this case, gear changingalways takes place without the driver having to use the clutchpedal. If the EDC cruise control is engaged, gear change isautomatic without the cruise control being disengaged. Thisapplies until speed is so low that it is a question of stopping orshunting. The clutch must then be used.

In addition to the driving mode selector and its various posi-tions, the driver can choose between two different drivingprograms. This is done using a program selector beside thedriving mode selector. These programs are called Normal andHill. The Hill program is for steep upward slopes with morethan 5 % gradient.

Introduction

Normal

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Hill


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General

The control unit varies the point at which it changes gear,depending on the position of the program selector. When driv-ing with the program selector set to Hill, gear changing isfaster than when the Normal program is engaged. If neces-sary, the exhaust brake may also be used in order to quicklyreduce the speed of the engine.

Like the older CAG system, Opticruise has a selectable start-ing gear which is programmed in one of the control unit mem-ories. The driver can easily select the starting gear for theaverage gross train weight of the vehicle combination. Thecontrol unit retains this setting, even when power is inter-rupted. In addition to this, the driver can temporarily select astarting gear other than the one programmed in the memory.This is fully described in the driver’s manual.

The control unit has a built-in warning system. This has madeit possible to reduce the inconvenience in the event of a fault.Opticruise has two built-in emergency driving programs. Thefirst of these, clutch mode, is activated in the case of less seri-ous faults and the driver has to depress the clutch pedal everytime a gear is changed. If the driving mode selector is set toautomatic, Opticruise still preselects the gear as normal. Inthis situation, Opticruise works in the same way as ScaniaCAG.

In the case of more serious faults, the driver should activate alimp home program. This makes it possible to drive the vehi-cle to a workshop, even if something like a sensor is faulty.This means that the vehicle can be run, even if the emergencydriving program feels basic with its manually-requested com-pressed air gear changes.

The Opticruise system interacts with the braking effect of thediesel engine, the exhaust brake and the Scania retarder, if thevehicle is fitted with this. This reduces brake wear, reducingrunning costs. In addition, wear to the entire powertrain isreduced as power is transferred more gently than on vehicleswith manual gearboxes.

However, the greatest advantage, not least financially, is ofcourse improved driver comfort. Opticruise enables the driverto maintain concentration longer than when driving a vehiclewith manual gear changing. This is an advantage for both run-ning costs and road safety.

CLU MODE

LIMPHOME


General

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Controls and operation

The above drawing shows the controls used forOpticruise. The clutch pedal, controls for EDCcruise control and auxiliary brake control unitalso affect the system.

For example, the auxiliary brake may requestthat the engine brake program be activated inorder to increase engine speed and thereforecoolant flow. This is essential for optimumretarder performance.

When driving with the cruise control, the sys-tem changes gear automatically provided thedriving mode selector is set the position A. Thecruise control is deactivated using the clutchpedal, brake pedal, retarder lever, cruise con-trol OFF button or using the exhaust brakeswitch on the floor.

1 Driving mode selector with positions R, N,A and M. The driver is able to command upand downshift by moving the selector leverto the side.

2 Program selector with Normal and Hillpositions. The Hill position is for use onsteep slopes, preferably with the drivingmode selector set to M (manual).

3 Switch for activating engine brake pro-gram and exhaust brake.

4 Diagnostics switch

5 Gear indicator with display and buzzer.


Description of operation

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Gear changing

Driving in automatic position A means that thesystem changes gear automatically in accord-ance with the driving program set using theprogram selector, either ”Normal” or ”Hill”.

However, the gear selected automatically canbe changed at any time by the driver by mov-ing the driving mode selector to the side. Thecontrol unit always checks that the driver’sselection is within reasonable limits.

The driver can even preselect a gear thatappears completely inappropriate under the cir-cumstances, such as 3rd when driving in 7th.There are two conditions that must be met forthis to work.

• The vehicle must lose speed (be retarded).

• The driving mode selector must be set tomanual and the program selector to Hill.

The gearbox then starts the shift by first goingto neutral. The control unit then prepares itselffor the correct splitter level, correct lateralstroke and the correct range before road speedis reduced sufficiently for the particular gearchange to be requested.

At the same time, engine speed is automati-cally increased to high idling, about 2500 rpm.When road speed has decreased sufficiently,the gear is engaged smoothly and gently. Whengear changing is complete, control of theengine is returned to the driver.

When driving, the driver can at any time movethe driving mode selector to neutral (N) when,for example, approaching a traffic light. If hechanges his mind and the vehicle is still mov-ing, it is possible to move the driving modeselector back to one of positions A or M. Thecontrol unit then selects a suitable gear, basedon the speed of the vehicle and other informa-tion from sensors etc. It is not necessary to usethe clutch unless speed is too low.

From automatic position A, the driver can atany time move the lever to manual position Mand vice versa. This can be useful if you, forexample, want to ”lock” a gear on a slipperyroad surface. The same applies if he wants toshift manually, for example on steep hills.

Note: On uphill slopes greater than 8 %, it maybe necessary to drive with the driving modeselector set to M and with the program selectorset to ”Hill”. This gives the fastest possiblegear changing, which means that the vehicledoes not lose so much speed during changing.

Opticruise controls the engine via EDC

Gear changing when driving is done byOpticruise controlling the engine via EDC tosynchronous speed for the gear that is about tobe engaged, without the driver using the clutchpedal. This means that both engine speed andtorque are adjusted to precisely the levelrequired by the gearbox.

In order to make gear changing easier, enginetorque is reduced in a controlled manner justbefore the gear is disengaged.

Gear changing takes place after the speed ofthe moving parts in the gearbox has been syn-chronized.

Towards the end of gear changing, enginetorque increases in a gentle and controlledmanner to the level requested by the driverusing the throttle pedal. This means that gearchanging is always gentle and precise, increas-ing the service life of the entire powertrain.

This precise control is made possible by com-munication between the Opticruise and EDCcontrol systems.



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Description of the gear changing process

1 Gear change requested automatically or by the driver.

2 Engine regulated so that there is no torque on the gearboxinput shaft.

3 Gearbox set to neutral.

4 Engine regulated to synchronize the speed of the gearboxinput shaft and the moving parts for the gear to beengaged.

5 Gear engaged.

6 The engine is regulated to the required torque. TheOpticruise then returns control of the engine to the driver.

• During certain upshifts, the exhaust brake is used to morequickly brake the engine to the correct speed in relation tothe gear selected.

• When driving in automatic (A), the control unit continu-ously calculates which gear is most suitable. When this cal-culation shows that a gear other than the one engagedwould be more suitable, the gear change takes place imme-diately. This may be either a single change or a blockchange.

The calculation of appropriate gear is made based on the fol-lowing data:

- Position of program selector

- Current road speed

- Current acceleration

- Current torque

- Total gear ratio

- Throttle pedal position

- Any request for the activation of the engine brake programfrom the driver or from the auxiliary brake control unit.



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Engine brake program

The function of the engine brake program is togive optimum engine braking in all drivingconditions. The engine brake program hasnothing to do with the Normal/Hill programselector, but is controlled by a separate switchon the floor of the cab.

In order to use the engine brake program, thethrottle pedal must be fully released.

A short press on the floor switch is all that isrequired to activate the engine brake program.

This means that upshift is delayed as the con-trol unit maintains the gear for longer beforechanging up, increasing engine brake output.

However, if the floor switch is held down allthe time, the exhaust brake is also engaged anddownshift takes place earlier.

If the brake pedal is held down, the upshiftpoints change. The control unit is informed ofthis via the brake lamp switch.

The engine brake program is connected untilthe throttle pedal is next depressed.

If the vehicle is equipped with an auxiliarybrake system with Scania retarder, the enginebrake program can be automatically engaged(if appropriate) when using the retarder. This isdone by the auxiliary brake control unit. Theintention is to raise engine speed and thus cool-ant flow, providing the retarder with maximumbraking effect and activation time.

Programming start-off gear

The system permits free choice of starting gearbetween 1st and 4th. 1st or 2nd are normallyused, but it may be appropriate to use anotherone in extreme cases.

Note: When the vehicle is heavily loaded, 1stor 2ndmust be used. Otherwise, the clutchwill be subjected to excessive wear.

It may sometimes be necessary to start in agear other than the one programmed. This canbe done, irrespective of whether the drivingmode selector is set to A or M. Simply movethe driving mode selector to the side until therequired gear is shown on the display. Thevehicle can now be started. The ordinary start-ing gear remains programmed in the controlunit memory. More information can be foundin the driver’s manual.

Kick-down

By pressing the throttle pedal from full throttleto kick-down, the gear changing points areraised, usually causing faster downshift.

Auxiliary brake system

See ”Engine brake program”.



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EDC Cruise control

When driving with the cruise control, the system automati-cally change gear if the driving mode selector is set to A. It ishowever still possible to manually control gear selection inboth positions A and M, without disengaging the cruise con-trol.

If the driving mode selector is set to N when the vehicle isbeing driven with the cruise control activated, engine speed isincreased to high idling (i.e. the engine surges). The drivershould therefore disengage the cruise control before settingthe driving mode selector to N.

The cruise control is disengaged using the clutch pedal, brakepedal, retarder lever, cruise control OFF button or the exhaustbrake switch on the cab floor.

ABS/TC

The Opticruise control unit communicates with the ABS/TCsystem. If there is wheel lock (causing ABS control) or spin(causing TC control), the Opticruise is very reluctant tochange gear and does so according to special criteria. Whenthe driving mode selector is set to A, the Opticruise endeav-ours to maintain the engaged gear.

Power take-offs

The control unit is configured for two types of power take-off,PTO EK/ED and PTO EG.

PTO EK/ED provides torque compensation and therefore verysmooth gear changing if the vehicle is driven with an engine-driven power take-off engaged (Max. compensation 200 Nm).

If the ED120 is used to drive a hydraulic pump, there may bea lack of space around the longitudinal stroke cylinder. If thisis the case, turn the longitudinal stroke cylinder the other wayand move the compressed air couplings so that they swapplaces.

PTO EG is for gearbox-driven power take-offs. If the vehicleis driven with this input signal active, all gear changing isblocked. The text PTO also flashes on the display if the vehi-cle is driven above a certain speed.



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Miscellaneous

Control unit configuration

The control unit contains all programming nec-essary for a number of different Scania ver-sions. So that the control unit fits each Scania,it must first be configured so that it uses thecorrect program for the particular vehicle. Thisis equivalent to the code plug in other (lessmodern) control units, such as for CAG.

The required configuration is fed into the con-trol unit at manufacture using a PC. Configura-tion may be changed later by qualifiedpersonnel.

Configuration must contain the followinginformation:

• Vehicle category (e.g. truck)

• Chassis number

• Part No. for control unit software

• Gearbox type

• Engine type and version

• Rear axle ratio

• Wheel rolling radius

• End-of-line data (date, signature)

Power supply and fuses

Generally, Opticruise continues to work if afuse blows while the vehicle is being driven. Itmay, however, be impossible to start the sys-tem the next time.

The control unit is protected by two fuses:

• Fuse 41 is used for 30 supply.

• Fuse 5 is used for 15 supply.

Power to the control unit is usually interruptedusing the starter switch. What happens then isthat control unit 15 supply to pin 55 is broken.When this happens, important data is trans-ferred from the RAM to the EEPROM andstored there until the next start. The controlunit then goes into rest state, despite the factthat 30 supply from the batteries is still appliedto pin 19.

• If fuse 41 for 30 supply blows, or if a bat-tery cable is removed, data cannot be trans-ferred from the RAM to the EEPROM andbe stored. The control unit ”forgets” anynewly-programmed starting gear as well asnew fault codes.

• If fuse 5 for the 15 supply blows, data istransferred as normal from RAM to EEP-ROM and stored there. In this situation, thecontrol unit believes that the starter key hasbeen set to position 0. This means that it isnot possible to restart Opticruise until thefault has been corrected.



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The figure opposite shows which other systemsare connected to Opticruise and in whichdirections data is transferred.

Any faults are transmitted in the samedirection. This means that a fault in theABS/TC system can manifest itself in theOpticruise system, but not vice versa.

Where appropriate, the figure applies to alloptional equipment affected.

• The Opticruise is coupled to the EDC sys-tem to enable synchronous control of thespeed of the gearbox input and outputshafts. The particular gear change does nottake place until these speeds correspondwith each other.

The communication between the Opticruiseand the EDC covers a wide range of data,such as engine speed, requested and actualtorque, throttle pedal position, coolant tem-perature and cruise control.

Communication is via two CAN leads and isfor such things as executing engine-control-led gear changing and determining whichgear should be selected at any particulartime.

• The Opticruise is coupled to the ABS/TCsystem to receive information on ABS con-trol, TC control, wheel speeds etc.

The communication between Opticruise andABS/TC is used for confirming such thingsas the suitability of the gear selection. If thewheels are spinning or slipping, Opticruisewould be “fooled” into selecting the wronggear. The speed of each wheel is also usedto check that other speed signals appearplausible.

Communication is via the two CAN leads.

• Opticruise is coupled to the auxiliary brakesystem to make it possible to engage theengine brake program to optimize theretarder and achieve maximum brakingpower in kW.

When the auxiliary brake has requested theexhaust brake to retard the vehicle, theOpticruise will still be able to control theexhaust brake for gear changing.

When the gear change is complete, theexhaust brake will again be used to retardthe vehicle. Prioritization of the varioustasks of the exhaust brake is controlled bythe exhaust brake control unit (EEB).

If the vehicle has an auxiliary brake, theOpticruise forwards the speed signal fromthe speed sensor on the gearbox output shaftto the auxiliary brake control unit.

• Opticruise is connected to the tachograph sothat it can use the speed information fromthis to check that other speed signals arereasonable.

Interaction with other systems



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OpticruiseABS/TC

Exhaust brake

EDC

Auxiliary brakesystem with

Scania retarder

Signal paths between the Opticruise control unitand other computer-controlled systems thatmay bein the vehicle.

Any faults are transferred from one system toanother in the same direction as communication(see arrows).

Tachograph



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Opticruise, design

Item numbers refer to the drawing opposite.

1 The floor switch is used to activate theengine brake program and exhaust brake.In vehicles with no auxiliary brake, theexhaust brake is used in combination withthe engine brake program when the floorswitch is held down. The signal goes viathe auxiliary brake control unit if the vehi-cle has this. Also see point 14.

2 Two switches provide data on the positionof the clutch pedal (released, partly or fullydepressed).

3 EDC informs the control unit that thedriver is braking. The engine brake pro-gram then uses slightly shifted upshiftpoints.

4 The tachograph provides a speed signalwhich Opticruise compares with the otherspeed signals. These come from ABS/TCand the gearbox output shaft.

5 The throttle pedal sensor provides data onrequested throttle and kick-down. Thepotentiometer signal goes via the EDCcontrol unit.

6 The gear indicator with display and buzzeris used to display driving program, whichgear is engaged, fault messages etc.

8 The driving mode selector informs the con-trol unit about requested driving mode andif the driver wants to actuate the automaticsystem by commanding a change up ordown.

9 The program selector has two positions.The Normal position provides optimumfuel economy and the box changes gearcalmly and comfortably. The Hill modeprovides a faster gear changing cycle athigher engine speed.

10 Diagnostic socket for PC via interface(Scania VCI).

11 PC with Scania Diagnos 2 fault tracingprogram provides the fastest result whenfault tracing.

12 The diagnostic switch is used to activatethe test program built into the control unitand for erasing fault codes.

13 Opticruise receives information fromABS/TC on speed, slip and possible wheelspin in order to select the correct gear atany moment. In addition, Opticruise mustbe able to prevent gear change if the drivewheels lose grip. This is for safety.

14 Opticruise uses the exhaust brake to adaptengine speed during certain gear changingprocedures, but the exhaust brake is nor-mally used to brake the vehicle.

The exhaust brake control unit prioritizesrequests depending on driving conditions.The exhaust brake can be activated auto-matically, manually or by the auxiliarybrake control unit.

15 The engine speed sensor is used to be ableto synchronize the speeds of the gearboxinput and output shafts when changinggear. The signal goes via the EDC andthrough the communications circuit.

16 The solenoid valves on the gearbox carryout each gear change by releasing com-pressed air to the longitudinal and lateralstroke cylinders. In turn, the cylinders acti-vate the gear selector shaft.

17 The hall effect sensor and the confirmationswitches monitor and confirm gear chang-ing movement.



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18 The speed sensor on the gearbox outputshaft is used to calculate vehicle speed andto confirm other speed signals fromABS/TC and the tachograph. A corre-sponding output signal is relayed to theauxiliary brake control unit.

19 Control of engine torque and speed isrequested by Opticruise but carried out byEDC. Just when Opticruise is controllingthe engine, the control unit continuouslychecks that actual torque corresponds tothe requested level.

20 The auxiliary brake system control unit canrequest Opticruise to activate the enginebrake program.

21 PTO EK/ED provides torque compensa-tion during engine-controlled gear chang-ing and therefore an excellent level ofcomfort if the vehicle is driven with anengine-driven power take-off engaged.

22 PTO EG is for gearbox-driven power take-offs. When this input signal is active, allgear changing is blocked and the clutchcannot be used.

The drawing below is general and applies to all optional equipment affected. Only relevant sec-tions apply to vehicles with less equipment.

RETARDER

EDC

2 3 5

10 11

14

19

20 13 ABS/TC

14

6 8

12

9

18171615

OPTI−CRUISE

22

21PTO EK/ED

PTO EG

1008

62



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Warning system

The control unit takes various action in the case of faults. Thisis to prevent the fault having expensive consequences. Forexample, the control unit has two different emergency gearchanging programs. The first of these still provides good driv-ability while the second requires more from the driver. Theintention of this is that minor faults should not cause too muchinconvenience.

Certain types of less-serious fault cause the control unit toswitch from normal operation to the simpler of the two emer-gency gear changing programs. The text ”CLU MODE”(clutch mode) is shown on the gear indicator display. In thiscase, the driver is required to use the clutch for each gearchange. While the control unit is working in this mode, theletter C will be displayed near the left of the display.

If the fault disappears on its own, the control unit immediatelyreturns to normal operation. The display then shows ”NOR-MAL”.

In the case of more serious faults, ”FAILURE” is displayed. Ifthis happens when driving, the control unit locks the engagedgear. This gear alone is shown on the display. The driver mustthen stop the vehicle and activate the ”LIMPHOME” emer-gency gear changing program. This process is described indetail in the Opticruise driver’s manual.

Fault code messages

When the driver switches off the power, the message ”CHKCODE” is displayed if the control unit has stored any faultcodes during driving. This message is repeated when thepower is switched back on again.

”ERROR1” or ”ERROR2” means that the control unit hassupplied faulty signals or no signals to the display. A PC mustbe used to read any fault codes.

”CONFIG” means that the configuration of the control unit isnot correct. In this case, change the configuration of the con-trol unit using a PC and Scania Programmer.

CHK CODE

CLU MODE

C

NORMAL

FAILURE

ERROR2ERROR1

CONFIG



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Reading fault codes

Fault codes are read in the first part of the Opticruise test pro-gram. This test program is described in full on pages 59 - 69of this booklet.

However, describing how to read fault codes would be a suita-ble introduction to the list of fault codes in the next chapterand the method is therefore also shown here.

1 Stop the vehicle and switch off the engine.

2 Switch on the power using the starter key.Wait for fiveseconds and then hold the diagnostic switch depressed forat least a half second. Release it. ”TESTING” is shown onthe display and the buzzer sounds.

Do not touch the diagnostic switch for the moment. Thetest program has now started. All parts of the display lightfor one second and the buzzer sounds.

3 ”ECU NO” is displayed, directly followed by the partnumber of the control unit hardware.

4 ”PROG NO” is displayed, directly followed by the partnumber of the control unit software.

5 ”CHASSNO” is displayed, directly followed by the vehi-cle chassis number.

6 ”F CODES” is displayed, directly followed by any faultcodes stored. More on this below.

• The fault codes are displayed one at a time, with two sec-onds between them.

• When all stored fault codes have been displayed, thebuzzer sounds briefly. The stored fault codes are then dis-played again. This may be repeated any number of times,so there is no danger if you should lose concentration.

The display can, for example, look like the figure to theleft. A shows the number of the fault code (10 in this case)and B shows how many times this fault code has been reg-istered (3).

7 Make a note of the fault codes. Run through the test pro-gram. Press the diagnostic switch to switch between thevarious stages of the test. See pages 59 - 69.

E010 003

A B

F CODES

CHASSNO

PROG NO

ECU NO

TESTING



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Erasing fault codes

It may be necessary to reset the warning systemevery now and then. Someone may, for exam-ple, have unplugged a cable while the powerwas switched on. This can easily happen and thecontrol unit will then believe that a genuine faulthas arisen.

The warning system is either reset using thediagnostic switch, concealed behind the coveron the instrument panel, or using a PC con-nected to the vehicle’s diagnostic socket in thecentral electric unit.

Fault codes are extremely useful in the work-shop as they facilitate fault diagnosis.

• In the driver’s manual, there is an explana-tion of how to erase fault codes. However, itis also advised that they should not be erasedunnecessarily and that it is preferable, if pos-sible, to seek advice at a workshop.

The symbols for the various switches are on theinside of the lid. These can be seen when the lidis opened. The Opticruise symbol is shown tothe right.

ERASED!

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When the warning system is reset, all faultcodes are erased. Proceed as follows:

1 Switch off the power using the starter key.

2 Press the diagnostic switch and hold itdown. Switch on the power.

3 The buzzer gives a short signal. When thetext ”ERASED” is displayed, erasure iscomplete.


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Fault codes

Fault codes

General

The control unit acts fast and accurately, according to certaininstructions. It has no imagination and no judgement. When it dis-covers a fault, or anything it interprets as abnormal, it reactsimmediately and generates fault codes. The warning system iscapable of generating around 70 different fault codes.

Despite the advanced and ”farsighted” soft-ware, a fault can arise which the control unit isunable to distinguish from something whichmight happen during normal operation. If thisis the case, no fault code is generated. There isalways a limit to how complete monitoring canbe. This applies to all types of control unit.

Limitations

It is not only ”genuine” faults that lead to thegeneration of fault codes. It is sufficient thatsomeone has unplugged a cable while thepower was on. This can easily happen and thecontrol unit will then believe that a fault hasarisen.

As for cases of loose contact, the fault may nolonger be present, but the fault code is stored inthe control unit memory until it is erased. It isat least possible then to see which circuit thefault was in and look for the cause there, evenif there is currently no fault.

Faults that do not generate faultcodes

The following are the faults which do not causea fault code to be generated that we are awareof at the time of going to press.

• Fuse 5 blown (15 supply).

• Break in the diagnostics switch circuit.

• Break in the floor switch circuit.

• Break or continuous signal from programselector (Normal/Hill).

• Break in circuit to the exhaust brake controlunit. Fault code 14 is generated in some, butnot all, cases.

• Break to gear indicator.

• Broken lamp in gear indicator.


Fault codes

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Explanations

Several new terms are used in the fault codelist or in the connection diagram in group 16.These terms are explained below.

CAN: Stands for controller area network. CANcommunication is used to reduce the number ofcables in the vehicle. This is intended toincrease reliability.

Vehicles with Opticruise have a communica-tions circuit consisting of two cables, CANhigh (pin 38) and CAN low (pin 20).

In simple terms, CAN communication can belikened to radio technology. Data signalsthrough a CAN cable can be likened to radiowaves through the air.

When listening to the radio, the receiver is setso that one radio station is heard at one time.This is the only station that can be heard,despite the fact that there are many radio sta-tions broadcasting at the same time.

A control unit does more or less the same thingwith the data coming through a CAN cable. Itlistens for things such as information fromEDC on coolant temperature, receives thisvalue and uses it in calculations.

The control unit receives all CAN signals thatare sent through the communications circuit ina special memory. This memory can be likenedto a number of radio receivers, set to differentradio stations in order to hear several, particu-lar radio programmes at the same time. In thisway, the control unit always knows what ishappening.

This is nothing that a mechanic needs to worryabout.The only thing to remember is that it isnot possible to check CAN signals using a mul-timeter. This is not even necessary as we haveprecise fault codes.

EEPROM: Stands for electrically erasableprogrammable read only memory. Memory isretained, even if power is broken using thestarter key. The contents can be erased andupdated during service, using a PC and ScaniaProgrammer.

This memory contains the control unit configu-ration, programmed starting gear, any faultcodes etc.

FLASH memory: This memory contains thecomplete basic programming of the controlunit. The content remains, even if power isswitched off using the starter key. The basicprogram can be changed during service using aPC connected to the diagnostic socket.

RAM: Stands for random access memory. Thecontent disappears every time the power isswitched off using the starter key or if power islost for any other reason.

This memory stores and processes the variouscontrol unit driving data from such things assensors, controls and adjacent systems (EDC,ABS and the retarder).


05:05-02 en © Scania CV AB 1995 21

Fault codes

Fault: Fault in integrated control unit memory.

Cause:Test calculation of content of FLASH memory did notprovide the result the control unit was expecting.

Comment: FLASH memory itself contains basic controlunit program. The control unit checks that the FLASH mem-ory is working as follows. All memory addresses are addedtogether to provide a sum. This sum is then used in a test cal-culation which must provide the ”correct answer”. Otherwise,this fault code is generated.

Action: Change control unit.

Fault code 1


Cause:Test calculation of content of EEPROM memory didnot provide the result expected by the control unit.

Comment: EEPROM memory contains the configuration ofthe control unit. Configuration controls which parts of thebasic program are used for the particular vehicle. When thecontrol unit checks that the EEPROM memory is working, thefollowing happens. All values that are important for configu-ration are added up to a sum. This sum is then used in a testcalculation which must provide the ”correct answer”. Other-wise, this fault code is generated.

Action: Correctly configure the control unit using a PC. Ifthis does not help, change the control unit.

Fault code 2


Cause:The control unit’s test of the RAM has shown thatsome of the memory cells are not working properly.

Comment: The RAM is the actual working memory of thecontrol unit. It is here that all calculations are made.

When the control unit checks that the RAM is working prop-erly, the following happens. Firstly, the control unit writescertain values into the RAM and then reads these same valuesto check that they have not become confused . If the controlunit interprets any deviation, this fault code is generated.


Fault code 3


Fault codes

22 © Scania CV AB 1995 05:05-02 en

Fault: Break or short in circuit for UX supply.

Cause:Control unit has detected that power consumptionfrom pin 36 on the control unit (the so-called UX feed, +24V)is either too low or too high.

Comment: The control unit gives UX supply on pin 36 tosupply the sensors, controls and display with power. The UXsupply enables the control unit to sense both open and shortcircuits as they cause abnormal power consumption. It is thisabnormal power consumption from pin 36 which causes faultcode 4 to be generated.

Open circuit: The circuit consumes no current. Short circuit:The circuit consumes high current.

In order for the fault code to be regenerated, power consump-tion must suddenly change, due to something such as loosecontact. If the fault remains, the fault code is regenerated eachtime the control unit attempts to activate the UX supply.

High current in the UX circuit can be caused by such things asshorted sensors.

Action: Check the UX circuit, wiring and components.

Fault code 4

Fault: Fault in voltage supply in control unit.

Cause:Control unit could not confirm its own internal U15supply when the driver switched on the power using thestarter key.

Comment: The control unit started working when the powerwas switched on, despite it not being possible to confirm U15supply in the test circuit monitoring this.

When this fault arises, it is not possible for the EEPROM tostore new information. This means that the control unit ”for-gets” any newly-programmed starting gear, and any newly-generated fault codes. The number of faults is displayed as 1,even if there are several. It is possible to drive the vehicle, butit should be repaired as soon as possible as certain safety fea-tures may be jeopardized.


Fault code 5


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Fault codes

Fault: Fault in monitoring feature inside control unit.

Cause: The integrated watchdog relay does not activate whenthe control unit starts working, or this relay is already acti-vated when the driver switches on the starter power (thisshould not be the case).

Comment: The control unit has detected a malfunction in oneof its internal safety features. Each malfunction of this typecauses the watchdog relay to alarm, generating fault code 7.

If the watchdog relay does not activate, power supply is lost toall control unit outputs. Not even the starter gear can beengaged, making the vehicle unusable.


Fault code 7

Fault: Not possible to regulate engine speed to correct levelwhen changing gear.

Cause: The control unit has received a message from theEDC via the communications circuit (pins 20 and 38) whichindicated an incorrect response from the engine. The exhaustbrake may have been activated during gear changing withoutthe Opticruise requesting this.

Comment: Requested torque exceeds permitted value forengine-controlled gear changing when the gearbox has beenconfirmed to be in neutral. This can happen if a gear isengaged when the control unit is not expecting it. A possiblecause of this might be the slider in the gearbox breaking. Ifthis fault arises, the driver must use the clutch for every gearchange. CLU_MODE is displayed.

Action: Start by checking the sensor signals for gear positionand then the gearbox itself.

Fault code 14

Fault: EDC gives a torque which does not correspond to therequested torque.

Cause:When the Opticruise control unit requested a particu-lar torque via the communications circuit (pins 20 and 38),EDC responded with a response which Opticruise consideredto indicate impossible values.

Continued >

Fault code 15


Fault codes

24 © Scania CV AB 1995 05:05-02 en

Comment: Requested torque from Opticruise is ”translated”in this manner to actual control rack position in the injectionpump. The Opticruise control unit continuously checks thateach response of this type from EDC corresponds with theexpected result. If this fault arises, the driver has to use theclutch whenever changing gear. CLU_MODE is displayed.

Action: Check whether the EDC control unit has generatedany fault codes. Check that the EDC control unit has the cor-rect part number. Check connectors and wiring. End bychecking the position of the control rack in the injectionpump.

Fault: NO signal or impossible signal from driving modeselector.

Cause:The control unit has received a signal on at least twoof pins 10, 11, 28, 29, 47 and 48 at the same time, or there isno signal at all from the driving mode selector. These signalsare provided with UX voltage (+24V).

Comment: These signals are impossible as the driving modeselector can only be in one position at a time.

If this fault arises, the control unit does not ”obey” the drivingmode selector. Either there is no signal at all, or the controlunit has received conflicting signals in one of the followingcombinations:

Upshift and downshift at the same time (pins 10 and 28).

Reverse and automatic position at the same time (pins 48and 29).

Reverse and manual position at the same time (pins 48and 47).

Neutral and manual position at the same time (pins 11and 47).

Continued >

Fault code 19


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Fault codes

Action: Check the driving mode selector, connectors and wir-ing. Use wiring diagrams and a multimeter to check the driv-ing mode selector.

Fault: Impossible signals from clutch switches.

Cause: Control unit has sensed that pin 8 received a signalwhen there was no signal on pin 45.

Comment: The lower clutch pedal switch has been closeddespite the upper clutch pedal switch not being closed. Itshould not be possible for something like this to happen whendriving.

When these switches are activated, they are closed to systemearth (0V).

The gearbox cannot change gear automatically if this fault hasarisen. The vehicle can, however, be operated using the LIM-PHOME emergency gear changing program.

Action: Check both clutch pedal switches, connectors andwiring.

Fault code 22

Fault: Uninterrupted signal from the lower clutch pedalswitch.

Cause:Control unit has sensed that there was a signal for toolong on pin 8.

Comment: The clutch pedal switch cannot be closed for thislong when driving normally.

When this switch is activated, it is closed to system earth(0V).

The gearbox cannot change gear automatically if this fault hasarisen. The vehicle can, however, be operated using the LIM-PHOME emergency gear changing program.

Action: Check the lower clutch pedal switch, connectors andwiring.

Fault code 23


Fault codes

26 © Scania CV AB 1995 05:05-02 en

Fault: Uninterrupted signal from upper clutch pedal switch.

Cause: Control unit has sensed that the signal remained fortoo long on pin 45.

Comment: The clutch pedal switch cannot be closed for thislong when driving normally, unless the driver rests his foot onthe clutch pedal when driving.


The gearbox cannot carry out engine-controlled gear changingin manual position if this fault arises.

Action: Check the upper clutch pedal switch, connectors andwiring.

Fault code 24

Fault: Uninterrupted signal from floor switch for enginebrake program.

Cause:Control unit has sensed that the signal remained fortoo long on pin 27.

Comment: The floor switch cannot be closed for this longduring normal driving.

When this switch is activated, it is closed to +24V. Note thatthe signal to pin 27 does not always come from the floorswitch. The retarder control unit can also send the same sig-nal.

If this fault arises, the control unit is forced to use the enginebrake program.

Action: Check the floor switch, connectors and wiring. Checkif there are any fault codes stored in the retarder control unit(if the vehicle has a retarder).

Fault code 26


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Fault codes

Fault: Uninterrupted signal from diagnostic switch.

Cause: Control unit has sensed that the signal remained fortoo long on pin 30.

Comment: It is not possible for the diagnostic switch to bedepressed this long during normal use.


If this fault arises when the driver switches on the power, allfault codes that can be shown on the display will be erased. Itmay also be impossible to start the test program.

Action: Check the diagnostic switch, connectors and wiring.

Fault code 27

Fault: Impossible deviation, vehicle speed compared to tach-ograph.

Cause: The control unit has sensed that the difference in fre-quency between the signals to pins 31 and 49 (which togethergenerate a frequency in the control unit) and the signal to pin32 is too great.

Comment: The difference between the signal from the induc-tive speed sensor on the gearbox output shaft and the tacho-graph signal from the combined instrument was greater thanpermitted.

Action: Check the road speed sensor on the gearbox outputshaft, the tachograph signal, connectors and wiring.

Fault code 28


Fault codes

28 © Scania CV AB 1995 05:05-02 en

Fault: Defective contact or loss of signal, vehicle speed sen-sor.

Cause: Control unit has sensed that the signals on pin 31and/or pin 49 are too uneven.

Comment: Speed signal from the inductive road speed sensoron the gearbox output shaft has varied more than permitted.Speed must exceed a certain limit for the control unit to regis-ter this fault.

Action: Check the road speed sensor on the gearbox outputshaft, connectors and wiring.

Fault code 31

Fault: Break or short circuit, vehicle speed sensor.

Cause:Power consumption too low or too high on pin 31and/or 49.

Comment: This fault can either be due to a break in the wir-ing or in the actual sensor, or to a cable being shorted to chas-sis earth or +24V. In this case, the control unit cannot feel thatthe sensor in question is connected.

Action: Check the road speed sensor on the gearbox outputshaft, connectors and wiring.

Fault code 34

Fault: Gear changing movement forward on the left-handside commanded but not confirmed.

Cause:No confirmation for forward longitudinal stroke (pin43) on the left-hand side (pin 42), despite several attempts toactivate the solenoid valves which release the compressed air.

Comment: The control unit counts both its own attempts andthose of the driver to change gear.

Continued >

Fault code 36


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Fault codes

Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is reaching the solenoidvalves. Then check that the confirmation signals from the halleffect sensors are transmitted correctly. Check the solenoidvalves for forward longitudinal stroke and left-hand lateralstroke, connectors and wiring.

Fault: Gear changing movement backward on left-hand sideordered but not confirmed.

Cause: No confirmation for rearward longitudinal stroke (pin6) on left-hand side (pin 42), despite several attempts to acti-vate the solenoid valves which release the compressed air.


Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is reaching these solenoidvalves. Then check that the confirmation signals from the halleffect sensor are transmitted correctly. Check the solenoidvalves for rearward longitudinal stroke and left-hand lateralstroke, connectors and wiring.

Fault code 37

Fault: Gear changing movement forward in centre positioncommanded but not confirmed.

Cause:No confirmation for forward longitudinal stroke (pin43), despite several attempts to activate the solenoid valvewhich releases the compressed air.


Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is getting to the solenoidvalves. Then check that the confirmation signals from the halleffect sensor are transmitted correctly. Check the solenoidvalve for forward longitudinal stroke, connectors and wiring.

Fault code 38


Fault codes

30 © Scania CV AB 1995 05:05-02 en

Fault: Gear changing movement rearward in centre positioncommanded but not confirmed.

Cause: No confirmation for rearward longitudinal stroke(pin 6), despite several attempts to activate the solenoid valvewhich releases the compressed air.


Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is getting to the solenoidvalves. Then check that the confirmation signals from the halleffect sensor are transmitted correctly. Check the solenoidvalve for rearward longitudinal stroke, connectors and wiring.

Fault code 39

Fault: Forward gear changing movement on right-hand sideordered but not confirmed.

Cause: No confirmation for forward longitudinal stroke (pin43) on right-hand side (pin 24), despite several attempts toactivate the solenoid valves which release the compressed air.


Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is getting to the solenoidvalves. Then check that the confirmation signals from the halleffect sensor are transmitted correctly. Check the solenoidvalves for forward longitudinal stroke and right-hand lateralstroke, connectors and wiring.

Fault code 40


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Fault codes

Fault: Gear changing movement rearward on the right-handside commanded but not confirmed.

Cause: No confirmation for rearward longitudinal stroke (pin6) on right-hand side (pin 24), despite several attempts to acti-vate the solenoid valves which release the compressed air.


Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is getting to the solenoidvalves. Then check that the confirmation signals from the halleffect sensor are transmitted correctly. Check the solenoidvalves for rearward longitudinal stroke and right-hand lateralstroke, connectors and wiring.

Fault code 41

Fault: Gear changing movement to the left commanded butnot confirmed.

Cause: No confirmation for left-hand lateral stroke (pin 42),despite several attempts to activate the solenoid valve whichreleases the compressed air.


Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is getting to the solenoidvalves. Then check that the confirmation signals from the halleffect sensor are transmitted correctly. Check the solenoidvalve for left-hand lateral stroke, connectors and wiring.

Fault code 42


Fault codes

32 © Scania CV AB 1995 05:05-02 en

Fault: Gear changing movement to the right commanded butnot confirmed.

Cause: No confirmation for right-hand lateral stroke (pin 24),despite several attempts to activate the solenoid valve whichreleases the compressed air.


Action: Start by checking the air hoses to the solenoid valvesand that the correct air pressure is getting to the solenoidvalves. Then check that the confirmation signals from the halleffect sensor are transmitted correctly. Check the solenoidvalve for right-hand lateral stroke, connectors and wiring.

Fault code 43

Fault: Gear changing movement laterally towards the centreposition requested but not confirmed.

Cause:The control unit has sensed that a confirmation signalfor lateral stroke to the left (pin 42) or a lateral stroke to theright (pin 24) is still present.

Comment: When the confirmation signal for the lateral neu-tral position exceeds 10 V and no solenoid valve is activated,a time count is initiated which then stops when the confirma-tion signals for lateral stroke are no longer present. This faultcode is generated if the time count is not completed within apredetermined time.

Action: Start by checking the air lines to the solenoid valvesand check that the correct air pressure is reaching the solenoidvalves. Then check that the confirmation signals from theHall-effect sensor are correctly received. Check the venting ofthe solenoid valves for left and right-hand lateral stroke, thereturn springs, connectors and wiring.

Fault code 44


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Fault codes

Fault: Loss of confirmation, rearward stroke.

Cause: Control unit has sensed the sudden loss of confirma-tion signal on pin 6.

Comment: For the control unit to be able to check if the sig-nal is lost, a complete gear change must first be completed.Five seconds after the control unit has received confirmationof the completed gear change, it starts to sense whether theconfirmation signal continues to be transmitted as it shouldbe. The control unit checks this until it commands the gearboxto carry out the next gear change. This fault code is generatedif, for example, the gear is ejected mechanically.

Action: Check the hall effect sensor, connectors and wiring.

Fault code 46

Fault: Loss of confirmation, forward stroke.




Fault code 45


Fault codes

34 © Scania CV AB 1995 05:05-02 en

Fault: Loss of confirmation, neutral position.


Continued >

Fault code 49

Fault: Loss of confirmation, right-hand lateral stroke.




Fault code 47

Fault: Loss of confirmation, left-hand lateral stroke.

Cause:Control unit has sensed the sudden loss of confirma-tion signal on pin 42.



Fault code 48


05:05-02 en © Scania CV AB 1995 35

Fault codes



Fault: No confirmation, neutral position.

Cause: Control unit has not received confirmation signal onpin 7 to confirm that the commanded gear change has beencarried out.

Comment: When the solenoid valve for neutral is activated,time measurement starts which is interrupted when the confir-mation signal for neutral position exceeds 10 V. This faultcode is generated if time measurement is not carried outwithin a preset time.

This fault code can only be generated when vehicle speed isgreater than 5 km/h or when the clutch pedal is fullydepressed.

Action: Check control cylinders, solenoid valve for neutralposition, compressed air lines, hall effect sensors, connectorsand wiring.

Fault code 50

Fault: Continuous confirmation signal, neutral position.

Cause: Control unit has sensed that the confirmation signalremained for too long on pin 7.

Comment: Confirmation signal may not remain too long afterthe command for forward longitudinal stroke or rearward lat-eral stroke has been given. This fault code can be generated ifthe gearbox is binding, for example in severe cold.

Action: Check control cylinders, solenoid valves, compressedair lines, hall effect sensors, connectors and wiring.

Fault code 51


Fault codes

36 © Scania CV AB 1995 05:05-02 en

Fault: Impossible confirmation (impossible gear positions).

Cause: Simultaneous confirmation from several gears at thesame time.

Comment: The signals are impossible because the Hall-effectsensor and the confirmation switches should only be able toconfirm one gear changing movement at a time.

Any of the following confirmations have come at the sametime:

Neutral and forward confirmation (pin 7 and pin 43)

Neutral and rear confirmation (pin 7 and pin 6)

Forward and rear confirmation (pin 43 and pin 6)

Right and left confirmation (pin 24 and pin 42)

Low range and high range confirmation (pin 41 and pin 5)

Low split and high split confirmation (pin 4 and pin 23).

Action: Check hall effect sensors, confirmation switches,connectors and wiring.

Fault code 52

Fault: Gear changing movement to low range commandedbut not confirmed.

Cause:No signal on pin 41.

Comment: No confirmation for low range, despite severalattempts to activate the solenoid valve which releases com-pressed air. Each gear changing attempt must take a certaintime in order to be counted.

Action: Check control cylinders, confirmation switches, thelow range solenoid valve, compressed air lines, connectorsand wiring.

Fault code 53


05:05-02 en © Scania CV AB 1995 37

Fault codes

Fault: Gear changing movement towards high range com-manded but not confirmed.

Cause: No signal on pin 5.

Comment: No confirmation for high range, despite severalattempts to activate the solenoid valve which releases com-pressed air. Each gear changing attempt must take a certaintime in order to be counted.

Action: Check control cylinders, confirmation switches, thehigh range solenoid valve, compressed air lines, connectorsand wiring.

Fault code 54

Fault: Gear changing movement towards low split com-manded but not confirmed.


Comment: No confirmation for low split, despite severalattempts to activate the solenoid valve which releases com-pressed air. Each gear changing attempt must take a certaintime in order to be counted.

Action: Check control cylinders, confirmation switches, thelow split solenoid valve, compressed air lines, connectors andwiring.

Fault code 55


Fault codes

38 © Scania CV AB 1995 05:05-02 en

Fault: Loss of confirmation, low range.

Cause: The control unit has sensed the sudden loss of confir-mation signal on pin 41.


Action: Check confirmation switches, connectors and wiring.

Fault code 57

Fault: Gear changing movement to high split commanded butnot confirmed.


Comment: No confirmation for high split despite severalattempts to activate the solenoid valve which releases thecompressed air. Each gear changing attempt must take a cer-tain time in order to be counted.

Action: Check control cylinders, confirmation switches, thehigh split solenoid valve, compressed air lines, connectors andwiring.

Fault code 56


05:05-02 en © Scania CV AB 1995 39

Fault codes

Fault: Loss of confirmation, high range.

Cause:The control unit has sensed the sudden loss of confir-mation signal on pin 5.



Fault code 58

Fault: Loss of confirmation, low split.

Cause:The control unit has sensed the sudden loss of confir-mation signal on pin 4.



Fault code 59


Fault codes

40 © Scania CV AB 1995 05:05-02 en

Fault: Loss of confirmation, high split.

Cause: The control unit has sensed the sudden loss of confir-mation signal on pin 23.



Fault code 60

Fault: Solenoid valve for forward longitudinal stroke is livewhen it should not be.

Cause: Control unit output to solenoid valve for forward lon-gitudinal stroke has been powered without the control unitcommanding this.

Comment: This fault code is generated if the control unit out-put for the solenoid valve in question has been powered forthe wrong reason, for example due to a short circuit to +24volts (e.g. in wiring). Otherwise, there is a fault in the controlunit itself.

Action: Disconnect the cable from pin 3 and measure using amultimeter. Then check connectors and wiring.

Fault code 61


05:05-02 en © Scania CV AB 1995 41

Fault codes

Fault: Solenoid valve for rearward longitudinal stroke ispowered when it should not be.

Cause: Control unit output to solenoid valve for rearward lon-gitudinal stroke has been powered despite the fact that controlunit has not commanded this.


Action: Disconnect the cable from pin 22 and measure usinga multimeter. Then check connectors and wiring.

Fault code 62

Fault: Solenoid valve for neutral position is powered when itshould not be.

Cause: Control unit output to the solenoid valve for neutralposition has been powered despite the control unit not com-manding this.



Fault code 63


Fault codes

42 © Scania CV AB 1995 05:05-02 en

Fault: Solenoid valve for low range is powered when itshould not be.

Cause: Control unit output to solenoid valve for low rangehas been powered despite the control unit not commandingthis.



Fault code 64

Fault: Break or short in circuit to solenoid valve for forwardlongitudinal stroke.

Cause: Power consumption too low or too high from pin 3 onthe control unit.

Comment: When the solenoid valve for forward longitudinalstroke is activated, the control unit can sense the followingcases. Break:Circuit not consuming any current. Short cir-cuit:Current in circuit too high.

For the fault code to be regenerated, power consumption mustsuddenly change, for example due to a defective contact. Ifthe fault remains, the fault code is regenerated each time thecontrol unit attempts to activate the solenoid valve in ques-tion.

High current can be caused by such things as shorted wind-ings in the solenoid valve coil.

Action: Check the solenoid valve for forward longitudinalstroke, connectors and wiring.

Fault code 65


05:05-02 en © Scania CV AB 1995 43

Fault codes

Fault: Break or short in circuit to solenoid valve for rearwardlongitudinal stroke.

Cause:Power consumption too low or too high from pin 22on the control unit.

Comment: When the solenoid valve for rearward longitudi-nal stroke is activated, the control unit can sense the followingcases. Break: Circuit not consuming any current. Short circuit:Current in circuit too high.



Action: Check the solenoid valve for rearward longitudinalstroke, connectors and wiring.

Fault code 66

Fault: Break or short in circuit to solenoid valve for right-hand lateral stroke.

Cause: Power consumption too low or too high from pin 17on the control unit.

Comment: When the solenoid valve for right-hand lateralstroke is activated, the control unit can sense the followingcases. Break: Circuit not consuming any current. Short circuit:Current in circuit too high.



Action: Check the solenoid valve for right-hand lateralstroke, connectors and wiring.

Fault code 67


Fault codes

44 © Scania CV AB 1995 05:05-02 en

Fault: Break or short in circuit to solenoid valve for left-handlateral stroke.


Comment: When the solenoid valve for left-hand lateralstroke is activated, the control unit can sense the followingcases. Break:Circuit not consuming any current. Short circuit:Current in circuit too high.



Action: Check the solenoid valve for left-hand lateral stroke,connectors and wiring.

Fault code 68

Fault: Break or short in circuit to solenoid valve for neutralposition.


Comment: When the solenoid valve for neutral position isactivated, the control unit can sense the following cases.Break:Circuit not consuming any current. Short circuit: Cur-rent in circuit too high.



Action: Check the solenoid valve for neutral position, con-nectors and wiring.

Fault code 69


05:05-02 en © Scania CV AB 1995 45

Fault codes

Fault: Break or short in circuit to solenoid valve for lowrange.


Comment: When the solenoid valve for low range is acti-vated, the control unit can sense the following cases.Break:Circuit not consuming any current. Short circuit: Cur-rent in circuit too high.



Action: Check the solenoid valve for low range, connectorsand wiring.

Fault code 70

Fault: Break or short in circuit to solenoid valve for highrange.

Cause:Power consumption too low or too high from pin 54on the control unit.

Comment: When the solenoid valve for high range is acti-vated, the control unit can sense the following cases. Break:Circuit not consuming any current. Short circuit: Current incircuit too high.



Action: Check the solenoid valve for high range, connectorsand wiring.

Fault code 71


Fault codes

46 © Scania CV AB 1995 05:05-02 en

Fault: Break or short in circuit to solenoid valve for low split.

Cause: Power consumption too low or too high from pin 2 onthe control unit.

Comment: When the solenoid valve for low split is activated,the control unit can sense the following cases. Break:Circuitnot consuming any current. Short circuit:Current in circuit toohigh.



Action: Check the solenoid valve for low split, connectorsand wiring.

Fault code 72

Fault: Break or short in circuit to solenoid valve for highsplit.


Comment: When the solenoid valve for high split is acti-vated, the control unit can sense the following cases.Break:Circuit not consuming any current. Short circuit:Cur-rent in circuit too high.



Action: Check the solenoid valve for high split, connectorsand wiring.

Fault code 73


05:05-02 en © Scania CV AB 1995 47

Fault codes

Fault: The EDC cannot provide a reliable value for throttlepedal position.

Cause: The control unit has received a message from EDCvia the communications circuit (pins 20 and 38) which showsthat the value from the throttle pedal sensor potentiometer isimpossible.

Comment: In this case, the communications circuit itself isprobably not faulty. Otherwise, the control unit would havegenerated a different fault code (fault code 82 or 83).

Action: Check whether there are any fault codes stored in theEDC control unit.

Fault code 76

Fault: The EDC cannot provide a reliable value for currentengine speed.

Cause: The control unit has received a message from EDCvia the communications circuit (pins 20 and 38) which showsthat the value from the engine speed sensor is impossible.



Fault code 77

Fault: Fault in power supply to control unit.

Cause: Control unit has sensed that there was no U30 powersupply when the driver switched off the power with the starterswitch.

Comment: The control unit has been switched off severaltimes in a row without being able to store its data from theEEPROM. This may be because the control unit has beenswitched off with no U30 supply connected to the controlunit. It may also be due to the control unit having beenexposed to strong disturbance which has caused the integratedprotective features in the control unit to act and restart itrepeatedly.

Action: Check the fuse for U30 supply to the Opticruise con-trol unit, connectors and wiring.

Fault code 75


Fault codes

48 © Scania CV AB 1995 05:05-02 en

Fault: The EDC cannot provide a reliable value for currentvehicle speed.

Cause: The control unit has received a message from EDCvia the communications circuit (pins 20 and 38) which showsthat the value of the speed signal is impossible.



Fault code 78

Fault: The EDC cannot provide a reliable value for brakepedal position.

Cause: The control unit has received a message from EDCvia the communications circuit (pins 20 and 38) which showsthat the value from the brake pedal sensor is impossible.



Fault code 79

Fault: The EDC cannot provide a reliable value for coolanttemperature.

Cause:The control unit has received a message from EDCvia the communications circuit (pins 20 and 38) which showsthat the value from the temperature sensor is impossible.



Fault code 80


05:05-02 en © Scania CV AB 1995 49

Fault codes


Cause: The control unit test of communications circuit mem-ory has shown that some of the memory cells are not workingproperly.

Comment: The memory for the communications circuit isused as a buffer to store information from adjacent systems(such as EDC and ABS) and then to sort this informationbefore it is used by Opticruise. The control unit starts by feed-ing specific values into the communications memory and thenreads these same values to check that they have not becomeconfused. If the control unit detects any deviation, this faultcode is generated.


Fault code 81

Fault: Fault in communications circuit.

Cause:The control unit has sensed that the signal level in thecommunications circuit has been faulty. This indicates anopen or short circuit somewhere beyond pins 20 and 38.

Comment: When the signal level fault has ceased, communi-cation starts to work again with no further action.

Action: Check connectors and wiring. If these are not at fault,then the control unit is faulty, but there is not much chance ofthis.

Fault code 82

Fault: No communications signal from EDC control unit.

Cause: There has been an abnormally long delay in theexpected signal from EDC via the communications circuit(pins 20 and 38).

Comment: The Opticruise control unit continuously receivesinformation from the EDC control unit and ”realizes” thatcommunication is working properly. If this information is notpresent, fault code 83 is generated.

Action: Check to see whether there are any fault codes storedin the EDC control unit. Check connectors and wiring in thecommunications circuit.

Fault code 83


Fault codes

50 © Scania CV AB 1995 05:05-02 en

Fault: Impossible signal from throttle pedal kick-downswitch.

Cause:Control unit has sensed a signal on pin 44, despite thethrottle pedal not being fully depressed.

Comment: The kick-down switch closes to earth (0V). If afaulty analog value is received from the throttle pedal sensor,fault code 76 is generated, but the control unit cannot thengenerate fault code 85.

Action: Check whether there are any fault codes stored in theEDC control unit and if the Opticruise control unit has storedfault code 76. Check the kick-down switch in the throttlepedal sensor, connectors and wiring.

Fault code 85

Fault: No communications signal from ABS control unit.

Cause: There has been an abnormally long delay in theexpected signal from ABS via the communications circuit(pins 20 and 38).

Comment: The Opticruise control unit continuously receivesinformation from the ABS control unit and ”realizes” thatcommunication is working properly. If this information is notpresent, fault code 84 is generated.

Action: Check to see whether there are any fault codes storedin the ABS control unit. Check connectors and wiring in thecommunications circuit.

Fault code 84


05:05-02 en © Scania CV AB 1995 51

Fault codes

Fault: Incorrect gear ratio in gearbox.

Cause: The relationship between the speed of the input shaftand output shaft does not correspond to the gear engaged.

Comment: Input shaft speed is taken from the engine speedsensor. This means that the clutch must be fully released forspeed comparisons to be made.

This fault code can be generated if the control unit hasreceived confirmation that the clutch is released, but it is stillslipping. The fault code can also be generated if there arefaulty confirmation signals for gear position.

Action: Check if fault codes for gear positions or road speedsensors are stored. Check that the control unit is configuredfor the correct type of gearbox.

Fault code 86

Fault: Impossible deviation, vehicle speed compared to speedsignal from ABS.

Cause:Control unit has sensed too great a difference in fre-quency between the signals to pins 31 and 49 (which togethergenerate a frequency in the control unit) and the signal to pins20 and 38.

Comment: The difference between the signal from the induc-tive speed sensor on the gearbox output shaft and the speedsignal from the ABS control unit was greater than permitted.

Action: Check the road speed sensor on the gearbox outputshaft, fault codes in the ABS system, connectors and wiring.

Fault code 87


52 © Scania CV AB 1995 05:05-02 en

Fault: Impossible deviation, tachograph compared to speedsignal from ABS.

Cause: The control unit has sensed that the difference in fre-quency between the signals to pin 32 and the signal to pin 20and 38 was too great.

Comment: The difference between the signal from the tacho-graph and the speed signal from the ABS control unit wasgreater than permitted.

Action: Check the tachograph, fault codes in the ABS system,connectors and wiring.

Fault code 88

Fault: ABS cannot provide a reliable value

Documents

05:05-02 · play or using a PC and the Scania Diagnos program. The latter makes fault diagnosis quicker. Opticruise requires that the vehicle be fitted with both EDC and ABS/TC, due