Fix Error Codes: Troubleshooting ECU Issues

Hello everyone,

"This weekend, I replaced the battery in my parents' Passat B8 (2016), and afterwards, I got a bunch of error messages for things like the audio system (AAC), parking sensors (PDC), hill start assist, ABS, and lane keeping assist."
There were consistent voltage drops, communication errors, and a lack of proper calibration. Not a single defect was found.

I was unable to clear the errors, either through the batch service (nothing happened) or by opening each control unit individually. In the latter case, at least I received the error message: "The request to delete fault codes was not accepted by the control unit."

Unfortunately, I was in a hurry and didn't save the car scan data, nor did I take any screenshots of the error messages.

I then used the KTS 980 device from the company to prepare the two items for their journey home.

Kennt das jemand? Was habe ich übersehen? Step error?

Regards,

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Was the new battery properly installed and configured?

Rüdi wrote:

Was the new battery calibrated/programmed?

Yes, successful! All values have been recorded.
I could also clear all the errors in the gateway (diagnostics) and engine control unit afterwards. However, I can't do that for the rest of the system.

In such cases, it can be helpful to turn off the ignition, drink some coffee, start a new diagnostic session, and perform another bulk deletion.

Possibly, there was a software-related issue that caused a blockage at the diagnostic gateway.

Okay, dear community,

My father couldn't start the engine this morning. I sent someone over who used a generic tool to read the car's diagnostics. I won't be able to get there myself until Friday.

The following error messages are occurring:

Engine:
1) U112300 - CAN communication; fault/defect - Permanent.

Brake:
1) C114602 - Tire Pressure Monitoring System (TPMS), CAN signal error - Permanent.

Restraints:
1) U112300 - Frame CAN bus failure - Permanent.

ADAS:
1) U112200 - CAN bus; implausible message - Permanent.
2) U112300 - Frame CAN bus failure - Permanent.

He doesn't even get into the TPMS system.

What did I fry up while changing the battery?

I noticed in the wiring diagrams that all the mentioned control units are connected to the same fuse (SB32), except for the TPMS, which is connected to fuse (SB7).

I told my father to check the fuses with a multimeter. Both are good and receiving power. I guess I'll probably have to postpone it until the weekend.

Okay, for everyone who's bored on the weekend.

I was working on a car today. There are a huge number of errors in the car's diagnostic scan (attached). Some control units still won't allow me to clear the errors, and with others, the error reappears immediately.

Vehicle cannot be started!

The ADAC (German Automobile Club) was there temporarily and said that the "component protection" feature might have been triggered. They stated that without assistance from Volkswagen's customer service, nothing could be done.

Maybe someone has recommendations for other things I could watch?

Before the battery replacement, the car only had an occasional low oil pressure warning from the DSG (dual-clutch transmission), but it was still drivable. Everything else is new.

How do I start the car?

Okay, one more thing. I've checked ALL the fuses in both SB and SC. They're all fine!

Hi Bo,

Are the battery terminals securely fastened to the battery itself, or are they loose and rattling around (causing voltage drops)?

I consider component protection to be unlikely; there are other error messages for that.

Do you have an oscilloscope that you can use to directly connect to the power supply of the control units (fuse!)?

Without any damage to the wiring harness or water ingress, this appears to be caused by significant issues within the vehicle's electrical system or the CAN bus drive.

Best regards, Rainer.

At my parents' place, I only have a USB oscilloscope, which is always in the electronics kit in the car.

Okay, I'll start with the two devices that aren't responding anymore.

First, I need to secure them. We don't want them to break and disable the bus. Then, I'll check the connectors.

Thank you in advance. The information about component protection is already helpful because I'm not familiar with that and would have given up otherwise.

I'll get back to you when I know more. Probably tomorrow.

Does anyone know where the 120-ohm termination resistor for the comfort control units in the rear is located?

Another question - what interface are you using?
hg
Herbert.

Herbert wrote:

Another question - which interface are you using? hg Herbert

.

HEX-V2

Hi Bo.

As I interpret the Autoscan results, the problem seems to be in the CAN drive system, doesn't it?

Quote:

the comfort control units in the rear

Is the CAN comfort system completely separate from the CAN drive system?

It is only in the gateway control unit that the CAN drive, CAN diagnostics, and CAN comfort functions are integrated.

Best regards, Rainer.

dieselschrauber wrote:

Hi Bo. As I interpret the Autoscan, the problem seems to be in the CAN drive, or not? Quote: the comfort control units in the rear Is the CAN comfort system completely separate from the CAN drive system? https://www.canhack.de/viewtopic.php?t=2351#6520 It is only in the gateway control unit that the CAN drive, CAN diagnostics, and CAN comfort functions are integrated. Best regards, Rainer

You've just made me pause for a moment.

My reasoning was as follows:
- ABS, parking assist, and ESP usually function normally after disconnecting the battery if the sensors have not yet been initialized (I tested by disconnecting the negative terminal last night).

- The ACC (Adaptive Cruise Control), lane change assist, and tire pressure monitoring system are all connected to the extended module, and they're all malfunctioning.

On the other hand, the parking assist system is not responding, but when I disconnect the connector, nothing changes.

I need to sleep on it.

Bitte gib mir den deutschen Text, den du übersetzt haben möchtest.

"The engine, transmission, adaptive cruise control, ESP, etc., are all controlled by the CAN bus system, which is where the control units with errors are showing up in your car scan."

Am I missing something?

Battery possibly connected with reversed polarity, and some control units may be malfunctioning.