Passenger Airbag Deployment

F

ferry

Member
Friend has just got into his Z4, started it up and the passenger airbag has deployed.
No obvious reason for it. The car wasn't moving, handbrake on.

Is this a thing on the E85? Is there a trigger we're not aware of?

First thing we want to do is make sure it's safe and the driver's side isn't going to fire off.

Then we need to look at the damage and how to repair it.
 
I have indeed. Here’s what you have to look forward to 🙂 Around 3 hours start to finish.

Did the pre-tensioners on the seat fire as well?

It’s not common from my years of tinkering with them thankfully. The BM technical manuals refer to multiple sensors which determine which airbags to fire. I never explored which ones they were exactly.

If you remove the glovebox you can reconnect a replacement airbag before pulling the whole dash out. When you reconnect the battery have some ear plugs in just in case :)
 

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Another thing to prepare for is possibly crash damage recorded on the airbag control units. At least that’s what I expected but fortunately managed to clear mine with no issues.
 
Street said:
I have indeed. Here’s what you have to look forward to 🙂 Around 3 hours start to finish.

Did the pre-tensioners on the seat fire as well?

It’s not common from my years of tinkering with them thankfully. The BM technical manuals refer to multiple sensors which determine which airbags to fire. I never explored which ones they were exactly.

If you remove the glovebox you can reconnect a replacement airbag before pulling the whole dash out. When you reconnect the battery have some ear plugs in just in case :)
Click to expand...

It hasn't fired the pretensioner as far as I can tell..I guess the seatbelt would need to be fastened/occupancy sensor activated?

My biggest concern is not knowing what triggered it, so don't know if something else would need to be fixed prior to plugging in a new one, or whether the driver's one might also go. It's done the windscreen, too, where the cover has sprung up into it.
 
Weird- I’d suggest putting a spare in and trying to see if fault goes again. Before putting a new dash in. Then I’d take it to an auto electrician to see if they can determine why this happened.
 
Wondering whether to put an insurance claim in at the moment, or whether that would write it off.

I'll try to borrow a code reader.
 
I fully agree with Paddy. That will be the end of your zed as you know it.

Defo worth reading the codes to see if it registered a fault on the electrics. It'll still show the Stage 2 firing as well.
I was going to see if INPA or Tool32 can be used to read the crash data. Your average code reader wont do that bit.
Its the history just before an airbag fired.

I did a little more digging. The only crash sensors on the Europe spec Z4 are the centre module and the left and right B-Pillar satellites.
2 modules have to sense the impact and agree for the airbag to fire.
The occupancy sensor and pre-tensioner engaged determine if the front and door airbags trigger.

For your passenger airbag to fire it feels like there's been a 12v short on the fire electric somewhere. Perhaps plugging a replacement airbag in isn't a good idea. Perhaps start with a voltmeter on the airbag connections to see if there's 12v supply?
 
Its not uncommon to find water damage to the centre module as its very close to the floor. That may have created a short to fire the airbag? I don't think I'd risk probing about with a multi meter though unless you are very sure about what you are doing, especially with the battery still connected.
 
Rockhopper said:
Its not uncommon to find water damage to the centre module as its very close to the floor. That may have created a short to fire the airbag? I don't think I'd risk probing about with a multi meter though unless you are very sure about what you are doing, especially with the battery still connected.
Click to expand...

No sign of any moisture.

Wondering if there's a path from cigarette lighter to airbag system
 
This is an alarming read, luckily sounds like nobody was hurt. Would like to see pictures if you can post any?
Hope it gets sorted, please keep us posted.
 
ferry said:
No sign of any moisture.

Wondering if there's a path from cigarette lighter to airbag system
Click to expand...
Dark humour in me had me chuckling at that comment. I’m picturing a guy finally looking forward to a relaxing smoke away from the madness of the world and as he presses the cig lighter …. BOOM the airbag explodes in his face. Queue the Hamlet cigar music!
 
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RMB said:
This is an alarming read, luckily sounds like nobody was hurt. Would like to see pictures if you can post any?
Hope it gets sorted, please keep us posted.
Click to expand...

Not much to see in a picture other than a deployed airbag.
 
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Street said:
Dark humour in me had me chuckling at that comment. I’m picturing a guy finally looking forward to a relaxing smoke away from the madness of the world and as he presses the cig lighter …. BOOM the airbag explodes in his face. Queue the Hamlet cigar music!
Click to expand...

I wasn't in the car when it happened but it would be a decent ad for Pampers, too, apparently
 
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