In the previous part I connected a new body control module (BCM) to my test bench. I was able to power it, access it and flash different firmwares. In the mean time, I also received a proper connector for T73a (the A-side connector of the BCM) with part number 5Q0 937 700 B, so I could properly wire the BCM to the test bench.

Now that I have installed dynamic tail lights and performed software coding using ODIS-S, I know that the adaptions and parameter set have changed compared to the e-Golf I used to restore the settings and adaptions for firmware 5Q0 937 084 DD with.

I wanted to test one more thing: what if I would downgrade from firmware 5Q0 937 084 DD to 5Q0 937 084 CQ and then try to restore it using ODIS-S? Index CQ is a firmware that is compatible with my car according to ETKA, and since the hardware of the new BCM is based on is H38 with part number 5Q0 937 084 CG, I should be able to flash it back to CQ. I could also have chosen to flash 5Q0 937 084 CG, but the software with index CP was already in the BCM in the car and I could not find a CP firmware file.

Using the firmware file FL_5Q0937084CQ_0253_S.frf (which was actually listed under the AUDI firmware files), I downgraded the BCM to CQ. This took about four minutes, and the parameter set and adaptions were still the same. I then connected with ODIS-S and restored the parameter set and adaptions. This time it worked, and the BCM was restored to the factory defaults but with the adaptions and parameter set of my e-Golf with dynamic tail lights.

The next step was to flash the BCM to EC again, but I took a intermediate step and flash it to DD first. I did that so I could see if this would affect the parameter set and adaptions (I created an adaption channel mapping after each attempt). This procedure was not so different from the previous part.

I know have the BCM with software index EC and the parameter set as intended. an even better result than before.

Autoscan

I kept track of all the adaption channels when performing the upgrades. For the ones interested, I have made the adaption channel maps available here. There are additional channels availble: from CQ to DD added 43 channels, and from DD to EC added 35 channels.

part 1 - part 2 - part 3