BMW Z4 airbag light on

[Mr Whippy]

I've made it come on, somehow, while swapping from non-sports seats to m-sports seats.

I think the occupancy sensor isn't working right (loom issue maybe, or just my shoddy connecting of wires )

Now, assuming that the occupancy sensor isn't working, will the car default to *occupied* for the seat, firing the airbags/pre-tensioners in an accident... or will it not activate them for some reason?


Just wondering on clarification here. Need to go to BMW for a new key soon, so might get them to see what the code actually is (might just have come up due to a plug popping loose while moving the seat, and it's actually all working fine, I have no idea), but the main worry is passenger safety. Logic says it'll default on (would be mad not to), but logic also says best to check


Any help on this issue much appreciated

Dave

[john_p]

Did you switch the ignition on or have the battery connected while the pretensioner was disconnected?

I had the same issue when I disconnected a door speaker cable fitting new speakers on an E46. BMW just cleared it next time the car was in for a service and never mentioned it, so you might get lucky when they get you a new key - although IIRC this does not require the car to be hooked up to the diagnostic machine, maybe offer to buy the service guy a crate of beer and see if he'll clear it

No idea whether it'd fire or not, but I suspect it would fail active (all airbags deploy rather than only applicable ones) than passive.

Edit: On the E39, the TIS CD mentions that the airbag will still fire if there is a fault with the seat occupancy sensor. I suspect the Z4 will be the same. Obviously if you are worried, check with the dealer.

Edited by john_p on Tuesday 5th May 14:16

[Mr Whippy]

Hmmm...

Did some testing last night with heavy ish stuff on the passenger seat, it seems that it started dinging at me and showed the seatbelt lamp, plugged in the belt and it went away. Did that twice.

So I'm fairly sure that it's at least half working, if not fully working (will test more just to be sure), and the seatbelt in switch is working fine too.


Maybe the dash lamp is on because at some point (had the seats in and out about 5 times each over an hour) I plugged/uplugged or something while the battery was connected...


I'll get BMW to check the code when I get my new key, reset it, and then keep my fingers crossed


Thanks for the help. It's good to know the E39 defaults to safety ON if they can be... it is the sensible default thing to do in the event of an error, and puts my mind at rest a great deal more along with the above for now

Dave

[john_p]

Yeah that makes sense, that seatbelt thing is annoying isn't it? I've had to put a seatbelt around heavy shopping more than once

I suspect the warning light just means "a fault has occured and not been cleared yet" rather than "it's completely failed".

[Mr Whippy]

Yep, went out at lunch (lots of tracks around work) with a friend in the passenger seat. Ding comes on, lifting arse off seat, it goes off, sit down again, comes on again, seatbelt on, goes off, seatbelt off, comes back on... etc etc

So thats nice.

My heated seat is now the problem. At first my drivers seat lights for heating came on then went off again straight away, realised the plug wasn't in right, fixed, working.
Passenger side, lights worked, but no heat. Then they started going off as above straight away. Now they are on again when pressed, but no heat. (I think since the seats have been from a scrapper, the passenger one has been fairly damp, and the damp is now coming out and things are starting to work )


Still, for anyone that wants to know, facelift M-sport Z4 seats will swap straight into a pre-facelift car loom using non M-sport seats! Just need to 100% work out what the passenger heating issue is, but I think I can sort that or that is my seat being defective in that regard for now

Dave