Hello all,

I usually search around the site to find my answers, so I never made an account. I can't seem to figure this one out, so I figured I'd see if I can get some help. The car was running fine with no issues. I drove it to the store, all was fine. I came back out of the store about 15 minutes later and the car would not start. Most of the annunciator lights came on and it went into immobilizer mode. It gave me several brake failure warnings and the windshield wipers came on and would not turn off. After messing with it for a little while, I could get it to crank and it would drive, but it felt like the power brakes were not functioning, the engine was barely staying running, and the transmission would hard shift.

What I've done so far:

I had the battery tested by interstate and it tested "moderate", so they warrantied my battery and gave me a new one. No change
I've checked the grounds that I could find and inspected the alternator to see if I could find any loose electrical connections at major junctions to no avail.

Does this sound like a BCM maybe? I've read the most similar issues I could find online and most people suggest looking at the left and right battery buses. I haven't done that yet, as I'll have to do more research to find out where they are. What else should I be looking for? I have a code reader, but there are so many codes and they are so random, it seems like that isn't going to help me much.

I appreciate any guidance. Thanks guys.

Chris

 

Is your alternator charging? Without proper voltage this car does all kinds of strange things.

 

I believe the alternator is charging, yes. This all happens before I even start the car though. I just put a new fully charged battery in it. I think I'm just going to replace the CEM and see what happens. I can't find anything else that seems like it could be the problem.

The battery is also getting drained very quickly just sitting there. I'm told that is a common sign of a bad CEM.

Chris

 

I was messing around with getting this thing out. I unplugged the 3 harnesses from it, checked to see if there was any corrosion or anything on the points. I didn't see any, so I plugged them back in. The battery was dead, so I jumped it off my truck and it cranked right up. No lights, no issues, runs and drives great. Is it possible the CEM just needed a reboot or something? I drove it all day today with no issue at all. Alternator is charging fine, no issues starting, no issues driving, shifts fine, no ABS warning, nothing.

Did I mention I hate electrical issues?

Chris

 

Glad it's back!

With a new battery, you might want to double check the electrical cleanness of BOTH sides of the battery clamps: posts and clamps.

MF