2012 Passat B7 1.6 TDI Electrical issues

[Twolitrepinto]

Wvwzzz3czce113380

[Twolitrepinto]

So today, I have gone and got yet another used throttle valve, fitted it (just the electrical plug) and still get the same fault code. It clears but comes back within seconds.
I just unplugged it, cleared the code and it still comes back up even with it unplugged.
i was expecting to see a "Signal too low" or "open circuit" code.

Monday,14,October,2024,14:59:47:16365
VCDS Version: Release 23.11.0 Running on Windows 10 x64
Ross-Tech: Home


Address 01: Engine Labels: 03L-906-023-CAY.clb
Control Module Part Number: 03L 997 557 T HW: 03L 907 425 C
Component and/or Version: R4 1.6l TDI H43 9982
Software Coding: 08114034032501080000
Work Shop Code: WSC 01357 011 00200
ASAM Dataset: EV_ECM16TDI02103L997557T 003003 (VW46)
ROD: EV_ECM16TDI02103L997557T.rod
VCID: 4DC76929BD52E0B2945-8018
Fault Codes have been Erased


1 Fault Found:
7300 - Throttle Position Sensor (G69)
P0123 00 [10100101] - Signal too High
MIL ON - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Priority: 2
Fault Frequency: 1
Mileage: 296225 km
Date: 2127.14.31
Time: 14:57:35


Engine RPM: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 15 °C
Intake air temperature: 14 °C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 12.649 V
Unlearning counter according OBD: 40
Throttle valve adapter: actual value-ANG_THR[0]: 99.997 %
Throttle_actuator_commanded_value-ANG_SP_THR[0]: 81.209 %
Throttle valve: activation-PWM_HBR_THR[0]: 0.000 %
Throttle valve adapter: uncond voltage actual value-V_THR[0]: 4.995 V
Throttle valve adapter: offset closed-V_THR_BOL[0]: 0.698 V
Throttle valve adapter: offset open-V_THR_TOL[0]: 4.600 V
Throttle valve adapter: status-LF_STATE_THR_DISP[0]: 0




Readiness: 0 0 0 0 0

It is currently not even plugged in. Am i even looking at the right part? I have a wiring diagram in front of me and it definitely says G69 is a 5 pin plug which corresponds correctly with what I am looking at.

Thanks again for any help.

[Crasher]

The G69 is on the same power supply from the ECU as a number of other devices such as the G247, G212, G581 and G40 use the same 5v power output so as you say, it can't be the ECU. The TB you tried was correct, 03L 128 063 AD. I wonder if the G212 EGR pot is spiking the system?

[Twolitrepinto]

I have just found the issue.
The resistance on the ground pin (3) was very high.
I decided to bite the bullet and pull the loom out and found this.
IMG_20241014_155936_730.jpg

[Crasher]

Was that on the corner of the head?

[daveo138]

Just wondering how common this ECU issue is?

I’m currently looking to buy a B7, so I’m making a list of things to look out for.

Are there any telltale signs of ECU problems to check for?

Thanks.

[Crasher]

It wasn't the ECU, it was rub through corroded wiring. Failure of the A and B 5v outputs on the ECU is common but difficult to confirm, sort of a £2k seat of the pants hope and pray.

[Twolitrepinto]

Was that on the corner of the head?

photo_2024-10-15_02-54-32.jpg

It was against the large plastic pipe that runs above the gearbox.

The original ECU from this car did come back as faulty also when it was originally sent off to be repaired, hence it was (unsuccesfully) cloned.

I'm having another 2 issues now though.

1: I keep getting P0571 Brake pedal sensor implausible signal. This is a new fault. I've replaced the switch, still the same.
I saw another post somewhere that stated replacing the ECM with a matching one cured the issue for them.
This has made my heart sink a little as This ECM is not quite a matching one, as i couldn't find one that matched exactly.
I have zero other fault codes now on any module other than this one.

2: The injector deviation minimum quantities are now way off, often jumping up to + or - 2 to 3, with a horrible diesel knock on acceleration.
This was not the case on the original ECM, when it did run, it was smooth and quiet. also the power delivery is very slow but kicks in more at higher RPM's, making me suspiscious that this ECM may have been remapped at some point in a previous life.
The software the car was running on before (original ECM) was an old pre dieselgate version, this one however is v9982.

Although this is not the correct ECU for the car, it was from a car running the same CAYC engine.

I did the injector quantity adaptations, coded in the injector codes that were stored on the original ECU, which match what are in the engine.
I also ran the VCDS function to adapt the minimum quantities, but it just times out after about 30 minutes of revving itself.

I'm thinking of getting the ECU flashed with the correct software for the 03L 906 023 FS. Could that solve these issues?

I also just replaced the ALT belt and tensioner (what a pig) and the O-ring in the between the thermostat housing and the block as I spotted a leak while in there (again, what a pig).

I'm so far into this now and I really don't want to give up as I feel like I'm getting so close.

P.s Do you have the ability to offline flash with ODIS?

Kind regards,
Rhys

[Crasher]

I can reflash on or offline with ODIS but I prefer the online using Software Version Management and that will just tell me it is the wrong one.

[Twolitrepinto]

So last night I spoke to the previous owner just to double check what the company who cloned the original ECU said.
He told me that apparently they didn't test it, they just cloned it.
So I just adapted the original ECU back to the car and voila, it seems to be running perfectly now with no faults.
So it seems this ECU is actually OK and the fault was indeed caused by that wiring all along.

Thanks so much for your help