My 525i 2004 will not start in the morning for the last 3 weeks now. All this is started when I park my car outside the garage and that night has thunderstorm.I have to unplug and plug back in the battery multiple times and it will start, then, that day I don't have problem restarting the car. Ive been getting different errors every morning (Drive Control Sys, Front Passenger Restrain, Engine fault, etc.)

So far, this is what I've done.
1. Changed the spark plugs
2. Changed 2 new batteries (Duaralast Platinum H8 AGM and Duralst Gold 95R-DLG).
3. I tried removing the IBS still not working.
4. Brought the car to local shop that specialize BMW and will charge me 2K to replace and code new DME (Electtonic Computer module). I declined.

I have my car back and I'm still doing the same thing every morning (unplugging the battery). Please advise or any suugestions before I spend 2k plus tax.

 

I think this thread belongs in a different forum.


I used to have trouble starting my 2006 525i too. It would throw all kinds of errors. The battery tested fine.
It was a little hard to diagnose but the fault was with the crankshaft position sensor. Once I replaced it, never had trouble starting the car and no faults occurred.

 

did you check to see that there isn't standing water in the spare tire well? your Micro Power Module is mounted down there, and doesn't like to go swimming.

Just a thought.