Bcm issue

[88reatt]

My Reatta is throwing a code for the bcm(body control module), which I believe, because vanity lights and dome light don’t work. However, when the battery is disconnected and then reconnected, or you remove the bcm fuse and put it back in, the bcm functions properly. But, when you turn the key on then off, it doesn’t work until you do one of those two things again. Is this another issue or is it just my bcm? Posted this in the Facebook group but it got zero responses so I’m counting on this. I also believe that my car does throw the b556 code.🙂

[Ronnie]

22 minutes ago, 88reatt said:

I also believe that my car does throw the b556 code.🙂

Could you check the codes again and see if the code is a b552 instead of a b556? A b552 code after disconnecting the battery or fuse is normal and isn't a cause for concern.

 

[EmTee]

I would check the connections at the BCM.  If you're lucky, you may be able to disconnect them without having to remove or disassemble half of the interior...  Look at the condition of the harness connector sockets and the 'pins' (actually PCB edge traces) at the BCM.  If they're dirty or green carefully clean them up with some stiff cardboard sprayed with contact cleaner.  If the contacts look OK, sometimes just disconnecting and reconnecting the harness is enough to burnish the contacts.  Spray with contact cleaner and carefully perform a couple of mate/de-mate cycles.  If that doesn't resolve the problem, then refer to the shop manual and check the resistance to ground on the harness ground pins identified in the wiring diagram.  Any significant resistance should be traced back to the associated body ground point.

 

FWIW, inoperable interior lights could result from a grounding issue as well.  Study the wire diagram focusing on the areas related to the observed problem(s).

[88reatt]

I will try these. It’s just weird how every single time the battery is disconnected and reconnected it works when you turn on the key but once you turn it off, it doesn’t work until the battery is disconnected again. It’s done that for over a year now which is odd.