My 2007 525i has had number of false electrical faults over the past year.

It started with "left taillight failure", occasionally "right taillight failure", now i get "TPM malfunction" fairly consistently.

I have replaced all the bulbs and both of the bulbholders. The lights are fine and I doubt that there is a problem with the TPM system.

Could this be the battery? It reads 12.52V with the car off after a couple of hours.

Could it be a ground fault? I disconnected the ground wire bundles from the frame and sprayed contact cleaner on the area to get a better connection to ground.

Thoughts? Ideas?

 

Is it the original battery? May or may not be the problem, but you are due anyway.

 

I think your battery is fine - 12.5V is a healthy battery. Notice TPM control module is locate in trunk floor under spare tire. Check this space for any sign of water.

 

Could be your battery. You have to measure system voltage while you are getting the error.

Also, does your VIN fall into the recall period for rear taillight grounding issue (5-series production from Mar 1, 2007 through December 31, 2009)?

 

Good point on the recall. Also, the recall on the battery grounding lug, which is also in the trunk.

 

It turns out that this "Left Taillight Malfunction" was actually the Left Front Angel Eye. Problem solved.

Still don't know about the TPM.

 

I also get the 'Left Taililight malfunction' sometimes. When I get the error, the tailllights are all fine except the RIGHT inner parking light goes out. It's not the bulb as replacing did not fix it.

When the automatic lights come on or off, I suddenly get the malfunction and it doesn't go away.

I'll try replacing all of the parking lights & high beams/daytimes and see if it persists.