PMM OCTOBER 2016 15

VEHICLETROUBLESHOOTER

DIAGNOSTIC TECHNIQUES

Over the last 12 months we’vecovered many of the greatfeatures and benefits ofautomotive diagnostics and

service information using the Bosch KTS andESI[tronic] 2.0 software. In this final part ofthe series we’ll piece together all of thetopics we’ve covered so far in a ‘real life’diagnostic case study.

As an extra special bonus, we were luckyenough to get our hands on a pre-launchsample of the brand new, next generationBosch KTS 560 and thought it would be agreat idea to put it to use for this issue. Thenew KTS 560 & 590 range of Bosch VCIshave had many hardware and performanceupgrades to ensure the compatibility of BoschKTS automotive diagnostics with advances infuture vehicle technology.

The problem vehicleA friend of the Bosch technical teamapproached us saying his engine MalfunctionIndicator Lamp (MIL) had just come on. Thecar in question was a 2010 VW Passat CCwith the 2.0 TDi CBBB engine – a veryclean, well-cared for vehicle with just over62,000 miles on the clock. There were noapparent fault symptoms or drivability issues,but the owner was concerned that the engineMIL warning lamp had been on for a day orso, then gone off for a while, but was now

back on and staying illuminated.Our first port of call was to get the

equipment out – the maiden diagnosticvoyage for the new and improved BoschKTS560, how exciting! As the car was apopular VW model, we knew that the 16 pinOBD socket would be found above the pedalson the driver’s side. However it wasreassuring to know that ESI 2.0 would giveus a diagram and description of the OBDconnector location, if needed. The KTS wasplugged into the car and we heard a beepfrom the VCI and confirmed that the greenLEDs were flashing, telling us that the unitwas powered up and ready to go (see Fig 1).

We launched Bosch ESI 2.0 program andthe Bluetooth icon in the top right cornersoon turned green, showing that the‘wireless’ connection was good. We then usedthe ‘VIN Identification’ function to quicklyretrieve the chassis number, then filtering forthe engine code – there were six possible RBKey selections to choose from. This was aPassat CC, so the identifier of ‘VWW3463’was the one we needed (see Fig 2).

It’s always good working practice to getan overall report on the diagnostic state of avehicle, so we ran the ‘System overview’feature using the System Search (F12) softkey. As you can see in Fig 3, there were no

This regular series of technical articles from Bosch focuses on how to get the best out of its ESI[tronic] 2.0 software, which is

used in conjunction with the KTS range of diagnostic tools for vehicle fault diagnosis and service function procedures.

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ROBERT BOSCH

KTS DIAGNOSTICS MADE ‘ESI’PART 11: DIAGNOSTIC CASE STUDY – 2010 VW PASSAT CC; MIL ILLUMINATED

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less than 23 ECUs on the car that werepresent and communicating, but there wasclearly a fault logged in the EDC17CP14engine controller. No network faults had beenreported in the ABS or transmission systemsso it would appear that this could be a fairlylocalised problem in the engine system. Atthis point we clicked on the ‘Save’ soft key inorder to start a ‘Protocol’ job report that couldbe added to throughout the job and presentedto the vehicle owner upon completion.

From the ‘Repair’ sub-tab, we accessedthe engine system and a read-out of the errormemory was performed. Only one fault codewas stored: P246F – Exhaust gastemperature sensor (bank 1, sensor 4),implausible signal – Static fault.

Fault memoryAs the fault code description text was in ablue hyperlink we knew that from here therewas a shortcut straight to the SIS troubleshooting instructions. Firstly, however, wewanted to save and then try to erase the faultmemory to see if it could be cleared in orderto determine if it was actually an intermittentfault. The error memory did indeed clearsuccessfully and after cycling the ignition andstarting the engine it was noted that theengine MIL was now not staying illuminated.

At this stage we decided it would be a goodidea to check the ‘Actual values’ in the systemand view the exhaust gas temperature sensorvalues that were being reported back to theECU. Using the handy search bar in the actualvalues section, the long list of parameters wasnarrowed down to only certain valuescontaining the letters ‘temp’ in their name.

We found three values of interest: 1. ‘Exhaust gas temperature upstream of

turbocharger’; 2. ‘Exhaust gas temperature downstream of

OXI CAT’; 3. ‘Exhaust gas temperature downstream of

particle filter’.

As you can see in Fig 4, the values lookedreasonable for a cold engine and this backedup our suspicion that it was an intermittentfault. However, it did seem a little strange thatwe could see values from three sensors in thesystem, but there was still a fault code pointingto an issue with a fourth, mysterious sensor.We looked in the SIS trouble shooting sectionsand found a detailed diagram of the exhausttemperature sensor positions – mystery solved!

This confirmed that the temperature sensorafter the DPF was, in fact, labelled as ‘Sensorno. 4’ (see Fig 5). Just as we would conduct adouble check to save a misdiagnosis, wedecided to unplug the sensor and re-read theerror memory. We found more DTCs relatingto sensor no.4 (see Fig 6) so we were nowsure that this was the sensor that neededfurther investigation in order to determine theroot of the problem.

At this stage, we went back to the DTChyperlink marked in blue for P246F errorcode and, as expected, ESI 2.0 took us

straight to the trouble shooting instructionsfor the exhaust gas temperature sensor. Herewe were able to read the full functionaldescription of the component, check thewiring diagram for the sensor configuration(see Fig 7) and then proceed to follow theguided instructions to test the supply voltageof the exhaust gas temperature sensor afterthe DPF.

VEHICLETROUBLESHOOTERDIAGNOSTIC TECHNIQUES

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“It did seem a littlestrange that we could seevalues from three sensorsin the system, but therewas still a fault codepointing to an issue with afourth, mysterious sensor.”

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Further investigation Working underneath the vehicle, we removedthe engine under tray, located the sensor andvisibly checked for any obvious physicaldamage (see Fig 8). Upon inspection nothinglooked untoward, so the multi-plug wasdisconnected and, using the KTS built inmulti-meter, we measured the voltage at pins1 & 2 of the harness end with the ignition on(see Fig 9).

The set value for the supply voltage islisted as 3.2V to 3.4V and the value measuredon the car was 3.32V, which was within spec.The measured value digits were, therefore,shown as green (see Fig 10). Just to be on thesafe side, the wiring harness to the sensorplug was tugged and wiggled whilstmonitoring the voltage supply in case therewas an intermittent open circuit in thesystem. The supply voltage was good at thetime of testing so we moved on to the next

stage of the instructions, which was tomeasure the internal resistance of thetemperature sensor.

Once more, using the KTS built in multi-meter, the test cables were swapped over tothe sensor connector (see Fig 11) and themeasurement of the sensor at ambienttemperature was 210 Ohms – this is alsowithin the specified tolerance (see Fig 12).These seemingly good results coincided withthe intermittent nature of the fault we wereinvestigating so we decided to refit the sensorconnector, clear the error memory and drivethe car up to operating temperature, to see ifthe engine MIL would be triggered again.

Sure enough, after about eight miles ofdriving the warning light was back on, so itwas back to the workshop to see if we couldconclusively find one of the measurementsout of range. Fortunately, by keeping theengine running at a ‘fast idle’ speed to keep

the heat in the system, the exhaust gastemperature no.4 sensor value was recheckedand found to be out of range. This was goodnews, as we were confident that this was themost likely cause of the ‘improbable signal’.

At this stage we informed the vehicleowner, as it is always good to keep the‘customer’ updated on the progress of the job.We asked him a few more questions to fill insome gaps about how the fault occurred and,as a result, we discovered that the car hadbeen driven through heavy rain and flashflooding before the fault occurred. With thisknowledge, we suspected that the sensor hadsuffered from some form of ‘thermal shock’.

Removing the suspectAfter being left to cool for a while, the faultyexhaust gas temperature sensor was removedfor closer inspection and we noted that it wasnot made by Bosch. Back into ESI[tronic],

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READERLINK 007 �18 OCTOBER 2016 PMM

VEHICLETROUBLESHOOTERDIAGNOSTIC TECHNIQUES

HAVE YOU MISSED ANY OF THE SERIES?

THE ENTIRE ‘KTS MADE ESI’ SERIES FROM BOSCH IS AVAILABLE TO VIEW AT: WWW.PMMONLINE.CO.UK

OR ON THE BOSCH WORKSHOP WORLD WEBSITE: WWW.BOSCH-WORKSHOPWORLD.CO.UK

the ‘Equipment’ tab was used to see if therewas a Bosch sensor listed for this applicationbut, in this instance, there was not. A newsensor was ordered and it was noted that thepart number had been superseded, meaningthat there had probably been some designchange to the new part (see Fig 13).

The solution?The new sensor was fitted (see Fig 14),engine under tray replaced and the errormemory erased before a thorough road testwas performed. With an assistant in thevehicle, we used the ESI 2.0 actual value,time profile data logger to analyse theperformance of all three exhaust gastemperature sensors during the road test. Asyou can see in Fig 15, the sensor values wereall behaving well and actually rosesubstantially upon acceleration, especiallybefore the turbo charger.

Back in the workshop the error memorywas re-read and found to be empty, whichwas great news. As a final step, the GlobalOBD II function was used to confirm that allof the system readiness tests had beencompleted and the engine managementsystem was operating correctly. Job done!

Case conclusionsSeveral weeks have now passed and thevehicle owner has (happily) reported that thecar has been fine. Therefore, by using theBosch KTS and ESI 2.0 along with a thoroughdiagnostic test and repair process, a first-time-fix was performed on this car, resulting in asuccessful repair and a very satisfied customer.

In summary, the Bosch ESI 2.0 systemhad great diagnostic coverage on this vehicle,and all of the required information andfunctions were readily available to allow usto accurately and efficiently diagnose andrepair the fault on this vehicle.

Signing offThis series of ‘KTS made ESI’ articles hasproved to be a real success with PMM’sreaders and Bosch diagnostic users alike. Wehope that you’ve enjoyed reading them andhave picked up some good information andtips along the way. In addition to theintroduction of the new KTS 560 & 590 unit,new diagnostic features and functions arealways being added to Bosch ESI 2.0, so we’dencourage you to explore and utilise these asyou improve your diagnostic processes.

PMM would like to say a big thank you toBosch’s Automotive Technical Team forputting together this invaluable collection ofarticles. It’s not the last you’ll see of them,however, as the team will be back in the futurewith some one-off ‘Troubleshooter’ articles,specially created for PMM’s readers!

To request further details about the Bosch

range of KTS diagnostic equipment circle 091

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“A first-time-fix was performed on this car, resulting in asuccessful repair and a very satisfied customer.”

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