T5 GP BCM Coding: Error After Replacement?

Hi everyone!

"I recently had a visit from a colleague who works on T5 vans and is experiencing issues with the footwell lighting. It's a T5 Combi van, with central armrest, switch panel, and a sliding door on the right side."
After the purchase, the car was converted into a campervan with features such as a raised roof, kitchen, and a second battery (not controlled by the BCM).
The T5 owner then also installed a hands-free system and an infotainment system.

The vehicle delivery specialist installed a trailer hitch and a gross vehicle weight reduction system, and in the process, replaced the body control module with a 087H unit.

While reviewing the coding of the BCM (Body Control Module), I discovered some unusual settings; it appeared that the coding was not compatible with the vehicle.

"Upon request, I have also enabled the auto-lock function. Interestingly, the Body Control Module (BCM) attempts to re-engage the central locking system every time the vehicle reaches 15 km/h. It apparently does not detect the current lock status."

Since I don't have the car with me right now, I'll send you the scan later.

I do have a list of the standard equipment as delivered (see appendix).

Is there a way to code the BCM flawlessly based on the information provided in the PR codes?

Greetings,

Peter.

Hello!

Now, finally, the complete scan confirms my fears.

The locks aren't providing any feedback. However, because so many individual settings affect the central control system, I lack a clear understanding of what is truly decisive.

Best regards,

Peter.

Quote:

The T5 owner then also installed a hands-free system and an MMI.

Is everything wired correctly (CAN), or are the diagnostic cables being misused?

It doesn't really fit the vehicle, but a while ago I had similar symptoms in a Polo 9N after a radio replacement... The system wasn't recognizing the closed state anymore.

All attachments collected.

Greetings,

Peter.

Hello,

regarding

Quote:

feedback on the closed state

.
Try to remove this by manipulating the combinations of bits 1 and 2 in byte 0.

Bit counting: 0-7, bytes 0-n.

Quote:

Is there a way to code the BCM flawlessly based on the information provided by the PR codes?

With a significant time investment, you should carefully check each option (checkbox) to ensure it's appropriate for the specific configuration.
That's precisely why arbitrary coding entries should never be made. It is mandatory to secure the "old" coding from the previous control unit.

The MMI (Multi Media Interface) and FSE (Freisprecheinrichtung) have nothing to do with changes to the vehicle's body control module.

Best regards, Rainer.

Hi Rainer!

"I had the T5 with me again. After a lot of trial and error, I simply took the BYTE0, 1, and 2 values from my own T5, since both T5s are almost identical. And lo and behold, everything works; there are no more errors from the central locking system. The lock feedback is correct, and the automatic locking and unlocking functions work perfectly."

Is there a way to decipher the bits that are not documented in VCDS?

Greetings,

Peter.

Thank you for the feedback!

Decoding undocumented bits: Of course, there are possibilities, but it involves a lot of effort. You need to compare configurations, recode things, and see what changes as a result.