I finally got the EEVC back, installed it in the car, and connected SIPS. The update then went through successfully and the car can now charge at Tesla Superchargers.
I’ve also noticed a few improvements since the repair. The 12 V battery charging voltage seems slightly higher, the car starts charging more quickly when plugged in, and the charging time estimates appear to be more accurate.
The work was carried out by Paul at
Rollingmotion Auto Electrical. He explained that the issue required changing the VIN stored in the memory and updating the checksum.
Before contacting him I spoke to a large number of automotive electricians across the country — probably more than 20. All of them declined the job because they had never attempted something like this before. Paul was the only person willing to try. He was upfront that he couldn’t guarantee success and that his fee would still apply even if the repair didn’t work.
The job ended up taking about six weeks, which was longer than the original estimate. I had to follow up several times for updates and was often told it would be finished shortly. In the end he said it took quite a bit of time to figure out how to solve the problem, which likely explains the delay. It would have been easier if the timeline had been communicated more clearly.
That said, I don’t want to be overly critical. This was clearly a difficult and unusual job and he was the only person willing to attempt it when everyone else refused. He ultimately solved the problem and the unit now works perfectly.
So if anyone else runs into this issue, Paul at
Rollingmotion Auto Electrical can fix it but it may take some time.