I was having a lot of electrical problems in my r53 (most of the warning lights on, no signal through ODB2 port) and eventually discovered pooled water underneath the carpeting in the driver footwell. I stripped the interior down and got rid of all the water and the leak (there was duct tape over the drain hole?)

Now for the electrical problems:
1. After drying everything out, i regained battery voltage to pin 16 of the OBD2 port, but still not communication with ECU.
2. I confirmed continuity on the databus line from the ECU to the OBD2 port, meaning that the ECU is most likely fried.

Options:
1. Replace ECU with one from a different car and attempt to modify the VIN in its software to match my car
2. Replace ECU, BCM, security module, key, and barrel from a donor car

Questions:
1. Is this logic sound? Do y'all agree on the ECU being the defining problem?
2. There's no guarantee that this will solve the problems but is this the proper course of action?

Thanks

 

Hi Nebula 1200,
I am sad to hear your Mini has become victim of the water god! on the floor, under the carpet, is a lug with many wires connected to it (by the exhaust tunnel hump) these wires are to common ground for your electric system (there is also another on the passenger side under the hood and just in front of the upper motor mount) Cleaning these up, may improve you cars electrical system and my prove to be the real problem. Good luck!

 

You can have continuity to all the modules and still be short to B+ or ground. Can you talk with any modules? Oscope/ signal pattern, what does it look like? And when you say ECU, are you talking about the DME or BC1?

 

I do not have an Oscope to see the signal pattern. I cannot talk to any module because the OBD scanner does not even recognize that it is plugged into the car, even though pin 16 is supplying batter voltage.

 

Given that the car still runs and idles, I'm going to check out the comm bus ground and the ground strap in the engine bay. Maybe I'll repin the OBD port for peace of mind.

 

Figure it out? I have a dead ODB port as well...