I think it’s time to take your car to a reputable indie shop that specializes in bimmers. The shop needs to have all of the proprietary BMW software to scan the various modules. But first, how old is the battery. Do you live in a cold climate like Minnesota? If so, have your battery tested. Why? These cars are rolling computers and whacky voltages cause whacky issues. Next, google “BMW E46 hidden OBC functions.” Test #9 shows the voltage as seen by the computer. Check and report back the voltage when the:
- ignition is in the run position with the engine off
- engine is idling
- engine is revving at 2000rpm.
To find a reputable indie shop that specializes in bimmers try
www.bimrs.org.