[SaintJerome]

I am trying to repair a 2021 X5 G05 from water damage and was making some progress, when I disconnected one of the seatbelts (they need to be replaced) and started the car (twice), which appears to have somehow created a permanent SAE error. I am not entirely sure if this is co-incidence but now things have gone badly wrong!!!

The park brake is still on, and no way to turn it off, to try and drive the car to remove the SAE error (which says it is a brake ECU system error).

But something has occurred to disable the 7 ECUs as per below in ISTA. The car can't be started normally, BUT when I pull the park brake button (to override the SAE error in testing) it seems to then apply power to these ECUs and the car runs fine. BUT can't turn off park brake.

Any thoughts appreciated, since there are a lot of issues now all at once. The ISTA test resulting in the ECUs below being gone, seems to occur before the SAE process which then applies power to the ECUs again - so it seems as though they are unavailable, because the car is disabling power to them...

[JoeAyalaM]

I hope that you find the solution, water damaged cars are often totaled because of electronics and the costs for replacing cabling.

I suppose you have already done this, but I would start by checking and cleaning, using contact cleaning spray, every connector for all computers and other equipment in the car, even those not in use, because they could be the source for a short circuited connection. Also checking and cleaning all power lines and grounds.