mvvette97

I got the big red battery light on my e500 the other day. I replaced both batteries and it's charging 14.2 volts. I tried to scan it for codes and was able to scan all the modules other than the battery control module. Any idea what could cause it to have no communication with that module? I have checked every fuse including the hidden fuses in the passenger footwell. I'm at a loss.

sunman2

I would check power and ground at the BCM first. If its good there your BCM is probably out. There is a rare change the CAN wires are damaged (especially if no mods were done) Which scan tool are you using?

mvvette97

I'm just using an Innova scanner. I went out today and the battery light was off. So I hooked the scanner to it and now it will communicate with the battery module just fine. It now just says low battery conven temp unavailable. I messed with it all afternoon and all at once it was fine. No warnings or anything. Worked good till I done a restart then got the low battery message again. I'm not sure what to do with this thing.

Plutoe

forget the forum FUYAA get a load test and learn the real story

Azeem

Did you ever resolve your issue? Have you tried disconnecting the terminal from battery control module and reseating it? I resolve the issue I was having with red battery symbol in dash the other day. I had posted my experience on benzworld.org forum.

mvvette97

yes I figured it out.There is a fuse box directly in front of the trunk battery with 5 or 6 fuses. Well all of the fuse terminals had a white layer of corroision. I took the fuse box apart and cleaned everything up and the low battery and big red light is gone and it now can communicate like normal. I happen to discover this when I had the car running watching through the rear window moving wires to see if anything changed on the dash. I happen to bump that fuse box enough one of the terminals started making connection.