[MMishev]

Hi guys,

The other day something really weird happened with my 2003 530i. I parked in the mall and when I came back, I unlocked the car, started it and wanted to open the sunroof. But I couldn't. I tried all the options - lifting it, opening it at full, nothing worked. And then I noticed that the passenger door was still locked. So, I pressed the lock button inside and the rear doors locked, the passenger door stayed locked, but the driver door didn't lock. I pressed it again to unlock the car and the rear doors unlocked, the driver door stayed unlocked and the passenger door didn't unlock again. So, I stopped the car, went outside and tried with the key - same exact thing happened. The passenger door stayed locked and the driver door didn't lock. Since I was in the mall, I decided to go home and check out what's going on there. So, I left the parking and after 2 minutes, I tried the sunroof again and now it was working. Then I tried the doors, and everything was fine this time.

I would really appreciate any suggestions you might have. Thanks

 

[acoste]

All the failing units you listed are using the P-Bus.

The central locking drive for the rear doors don't use the P bus. They have unshared wires going directly to the general module.

So you might have a faulty unit on the P-Bus which blocks the communication sometimes. This can be a broken wire (for example at the drivers / passangers door where the wires go from the chassis into the door) or any of the following stuff:
- General module
- Driver's door module
- Passanger's door module
- Sunroof module
- seat/steering column memory control unit
- control unit, driver's active seat
- control unit, front passanger's active seat

Watch these functionalities while using the car to see if they are working fine.

 

[edjack]

... or, it could just be a gremlin, esp if it doesn't happen again. Not unheard-of.

Just for kicks, measure the battery voltage after setting overnight. S/b 12.5+ The electronics are sensitive to battery voltage.

 

[MMishev]

Thanks a lot for the responses guys. I will watch the other things you have mentioned and I will also measure the battery voltage when I have a chance (or a device). It's been a few days now, and it didn't happen again, but I am still checking the 4 doors before walking away from the car hahah.