I think I repaired my Airbag Module!

[SimonAW]

So I have no one else to share a passionate fist shake with so I am going to vent my relief and happyiness here..

I've had electrical issues with our 2005 52k Z4 since I have owned it, randomly the indicators would stop clicking, roof would flash red, battery would drain after three days etc.. It would happen then fix itself then happen again but in the end we got fed up with it, put it in the garage 2 years ago on a ctek and got on with life. Other cars have been bought and the attention went onto them but the other day I saw a Z4 on the road and my wife and I decided we missed the car so the love for it has come back.

Pulled the Z4 out of the garage and noticed the airbag light was constantly on (that's new) and as usual all the electrics on the car were acting strangley. Bought a new battery and installed but no change.

After much research on this wonderful forum i came to the conclusion it was most likely the aribag module, so out came the tools and also out came the interior. I wasn't relishing buying a new module or going through the hassle of tryng to code it. The car has no MOT or Tax so it is stuck at the house, so lets try to repair it.

All the airbag modules looked okay apart from the module between the seats which looked not too bad but when I disconnected it i could see that there was evidence of corrosion. i got it on my workbench and noticed that one of the pins was so rotten half of it was missing. Looking in the car the remains of the pin was indeed stuck in the connector, which i managed to remove with patience and a pair of pliers. I disassembled the module, cleaned with contact cleaner and inspected it, the circuit board is covered in a protective coating and looked good and uneffected by water. I unscrewed the black plastic connector housing and gently slid it away from the board revealing the pins fully. All of the pins were fine apart from the one that had corroded and snapped off, so looking through my bin of old BMW bits I found a board with the same connector pins. The module went under the microscope and I unsoldered the broken pin and soldered in a new one, cleaned up the board and slotted the black plastic connector back into place.

On fitting it back in the car the electrics all spang to life, indicators clicked, the roof retracted, windows all worked after reprogramming etc...all seems good. Got my scanner out and cleared the airbag and...... it stayed off. Awesome.

So yeah, happy days. Just got to get it MOT'd and off to one of our memebers to get the roof motor moved to the boot so hopefully this won't happen again.

P.S the only thing left is the Buisness CD radio say "disabled" so that needs looking at if anyone has any ideas?

[smorris_12]

Man after my own heart; take it all to pieces and see what makes it tick!

I wonder what pin it was? My money would be on the kbus line.

[SimonAW]

Yes I should have taken some photos. It was one of the pins that is closest to the drivers seat as the module sits in the car, but I can't recall if it was the top or bottom row.

[Zulu4]

Brilliant
A mood lifting story.

[02/29/20Z4]

great information. thanks alot for sharing!

[Homer]

I’ve had this happen to me this week, I wonder if mine is the same. How difficult is it to get out?

[SimonAW]

There are plenty of guides on youtube etc, it's not hard to get out, but you need to remove a lot of the trim. I just took my time, used the right tools and it all came out pretty easily in about an hour.