Bug type faults in software.

[Hs-Autopalvelu]

In 2009 TDI A3 CAYC car that runs on three cylinder vcds showed injector 3 circuit fault. That is correct. While engine was running on three live data showed 0V at cylinder 2 instead of cylinder 3.
Then with new injector. Vcds did not want to code new correction value at all. It always showed value out of range nag.

I used other tester to code injector in without any flaw.

Vcds Release 26.9.0

 

[PetrolDave]

Please post a complete Auto-Scan made with the English version of VCDS

 

[Uwe]

While engine was running on three live data showed 0V at cylinder 2 instead of cylinder 3.

I'm pretty confident this is not a bug in VCDS but rather the software in your ECU. But as Dave noted, please post an Auto-Scan so we can see exactly what software is in your ECU, and then we may ask you to make some debug data so we can verify that the it is indeed the ECU that's reporting things incorrectly.

-Uwe-

 

[Hs-Autopalvelu]

Unfortunately I did not take complete system scan. There was no need to do it. I can not take it anymore since customer has picked the car up. Here's the fault list from the engine and save from the livedata.

Monday,31,August,2026,09:06:42:61407
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 26.3.0.0 (x64)  HEX-NET CB: 0.4701.4
Data version: 20260320 DS375.1
www.Ross-Tech.com


VIN: WAUZZZ8P6AA052874   License Plate:
Mileage:    Repair Order:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


                Address 01: Engine       Labels: 03L-907-425-V1.clb
Control Module Part Number: 03L 906 023 M    HW: 03L 906 023 L
  Component and/or Version: R4 1.6l TDI   H23 9979
           Software Coding: 00114016032401080000
            Work Shop Code: WSC 06314 000 00000
              ASAM Dataset: EV_ECM16TDI02103L906023M 003017 (AU35)
                       ROD: EV_ECM16TDI02103L906023DR_003_VW32.rod
                      VCID: 302C31C86BCC8C1F73-8064
1 Fault Found:

9839 - Injector: Cylinder 3 (N32)
          P0203 00 [11101101] - Circuit Malfunction
          MIL ON - Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 2
                    Mileage: 331685 km
                    Date: 2026.08.30
                    Time: 17:21:21

                    Engine speed: 2306.50 /min
                    Normed load value: 40.4 %
                    Vehicle speed: 117 km/h
                    Coolant temperature: 86  C
                    Intake air temperature: 25  C
                    Ambient air pressure: 990 mbar
                    Voltage terminal 30: 14.456 V
                    Unlearning counter according OBD: 40
                    Error information regarding selected piezo output stage-LF_STATE_PPS_SPI[0]: 0
                    Injector valve 2: capacity-CAPA_INJ_MAIN[1]: 17.7676  F
                    Voltage load of main injection cylinder 2-CHR_INJ_MAIN[1]: 1430.5  As
                    Measured energy of main injection cylinder 2-EGY_INJ_MAIN[1]: 57.586 mJ
                    Supply voltage of analog output 1-VCC_1: 4.99 V
                    Supply voltage of analog output 2-VCC_2: 4.99 V
                    Injection valve 2: voltage-V_INJ_MAIN[1]: 80.51 V


Readiness: 1 1 0 0 0

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


                Address 01: Engine  (03L 906 023 M)

09:10:31
  IDE03893-ENG101196   Injection valve 1: voltage-V_INJ_MAIN[0] 132.27 V
  IDE03894-ENG104143   Injection valve 2: voltage-V_INJ_MAIN[1] 0.00 V
  IDE03895-ENG101536   Injection valve 3: voltage-V_INJ_MAIN[2] 126.00 V
  IDE03896-ENG102925   Injection valve 4: voltage-V_INJ_MAIN[3] 128.89 V

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Address 01: DTCs cleared

 

[Uwe]

Unfortunately I did not take complete system scan. There was no need to do it.

The general rule when using VCDS is: Auto-Scan every car before undertaking any work on it. That way you have a record of its condition when it rolled into your shop. With modern cars, this typically takes less than three minutes and can save you plenty of grief in the future.

I find it interesting that the freeze-frame data has several values for INJ_MAIN[1], which corresponds to the IDE data you posted.

I wonder if the fault codes number the cylinders as they are oriented in the car and while the IDE data numbers them according to firing order?

-Uwe-

 

[HMC]

Uhumm. https://forums.ross-tech.com/index.php?threads/39052/#post-323100
regards HMC

Edit. To add to this I think the clue can be in the text, when there is reference to "cylinder" that is cylinder position, when there is reference to "Injector" that is often number by firing order.

 

[Uwe]

Uhumm. https://forums.ross-tech.com/index.php?threads/39052/#post-323100
regards HMC

Yes, we've seen this sort of thing before, which is why I said, "I'm pretty confident this is not a bug in VCDS".

-Uwe-

 

[Hs-Autopalvelu]

The general rule when using VCDS is: Auto-Scan every car before undertaking any work on it. That way you have a record of its condition when it rolled into your shop. With modern cars, this typically takes less than three minutes and can save you plenty of grief in the future.

I find it interesting that the freeze-frame data has several values for INJ_MAIN[1], which corresponds to the IDE data you posted.

I wonder if the fault codes number the cylinders as they are oriented in the car and while the IDE data numbers them according to firing order?

-Uwe-

I do not scan complete car if there is not clearly need for it. Every scans are stored anyway.

To the problem. Your thought about being cylinder numbering and firing order is correct.

 

[PetrolDave]

Every scans are stored anyway.

Only if you do an Auto-Scan, which has been already said is best practice. It's very common to see "sympathy" faults and chasing them is a waste of time, so seeing the FULL picture is important.

 

[nugentp]

To the problem. Your thought about being cylinder numbering and firing order is correct.

I suspect the ECU manufacturer would describe this as "a feature - not a bug" ;-)