My key fob does not work at all....and It has not since I purchased the car. I got a good deal on it, so I wasn't too concerned about the key fob at time of purchase. the actual key works for locking, unlocking and ignition...however the remote key fob functions are a no-go. After spending quite a few hours searching forums, I decided that maybe the rechargeable battery inside the fob had just died out...it is 11+ years old right? So I cut open the fob, which is a lot easier than others made seem, I had it open in about a minute with a carpet cutter blade. Tested the battery with a multimeter. 3.08 volts ....the battery was good...and as far as I can tell , is still charging when inserted into the ignition. Im pretty sure that the issue is with my car somewhere not the key/fob/battery.


Any suggestions on what to troubleshoot next?
my next step is to check fuses...maybe should've been my first step but whatever...


04' 545i, No-CA (diamond key fob)

 

Almost immediately after posting this a friend of mine noticed the solder on one side of the battery had broken...quick solder job annnnnnddddd, FIXED. Just a tip for anyone with a suddenly unserviceable key fob. Ill be purchasing a new case for the key soon, and transferring out the circuit board. Still a lot cheaper than replacing my key through the dealership :/

 

My fobs don't work unless I am within about 2-3 feet of the rear of the car. The stealership told me it is because of the tinting on the windows. Any thoughts on that?

 

I had a similar issue with my FOB. I had not remote lock. It turned out that the vehicle battery was dying. I replaced the battery and the FOB began working straightaway. The good news is these cars will warn you that your battery is going to fail you very soon.