Yep, another airbag light thread
I finally got my BMW scanner and hooked it up last night to see why my airbag light is on. I got two errors using PA Soft, 50 Power Supply Undervoltage, and F0 Internal Control Unit Fault. These codes won't clear. I also got a power supply code for the radio antenna, which came back after clearing it.
After some researching it seems that the SRS module might need to be replaced and/or my charging/battery system is dying. My alternator has never been replaced and my battery is getting pretty old, so no matter what I have to check these. I'm not sure what this power supply error for my radio antenna means, but it makes me suspect as well. The only other culprit I came across could be the battery safety terminal, although the airbag light only recently came on and my car has not been hit recently, nor hit hard enough for any airbags to deploy since I've owned it. Aside from testing the charging system and battery does anyone have any ideas on how to diagnose this without throwing a few hundred dollars in parts at it? I haven't seen this combo of errors yet.