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BMW airbag light help
sonic - 9/3/10 at 09:07 PM

Hello all

I have a BMW 316i se 2001 51 E46

The airbag light keeps coming on and off intermitantly.
Sometimes comes on for a few mins then goes out then stays on etc.

Seems to do it more often when somebody is in the passenger seat.

Any ideas about what to look for wiring plugs etc and where they are located

Thanks
Mick


SALAD - 9/3/10 at 09:18 PM

OK, prepare for vague-ness......something to do with the airbag occupancy sensor unit in the passenger seat perhaps?
Quite sure you can fool it into thinking you always have a passenger (thus always armed and ready).

I could be making this up so don't shout at me.


tomprescott - 9/3/10 at 09:45 PM

BMW's are famous for having random intermittent lights, had experience with 5 so far and all of them have had lights come on, either airbag or ABS.

Never got any of the problems sorted, checked the systems (which were all fine) and took the bulbs out! We bought a diagnostic kit once but didn't really help much - there a re a multitude of systems in operation that could be wrong so diagnosing where the fault actually is can be very difficult! Good luck


jambojeef - 9/3/10 at 09:45 PM

If this is the same problem as on e39s its easy to fix.

It is (as mentioned above) the occupancy sensor in the pasenger or drivers seat. Or rather the connection to the pad which has corroded / got damp / has ever so slighty more resistance for some reason throwing a fault code to the OBC.

To fix it you need to find the connector under the seat, which is the usual culprit. There are little gold plated connectors with blue and white wires (I think) which connect the sensor mat to the loom which emerges through the carpet under the seat. If you can find the connector (accessed, in the e39 anyway, from under the rear of the front seats) then you may get away with a clean or worst case scenario bypass the connector with a bit of nifty wiring.

Dont make the same mistake as I did and buy a box of tricks from ebay - its a diode and a resistor in a box for £20.

Once youve done this I had to have mine reset at my friendly local BMW garage and pay them a silly amount of money for the privelidge.

Hope that helps

Geoff


RichieHall - 9/3/10 at 09:55 PM

Ditto above!

I had the same problem with the old 316Ti, the problem connector is under the drivers seat and one pin would come loose every time the wife drove the car, seat all the way forward to drive and all the way back to get out!

I just gashed it with tye-wraps but a more permanent fix shouldn't be a problem, I was just worried about messing about with the airbag system, knowing full well that it wouldn't make a blind bit of difference!


britishtrident - 10/3/10 at 08:02 AM

Safety Warning! Disconect the Battery for 20 minutes Before Working on SRS Systems


SRS systems have a back up capacitor to store charge to safely work on the system give it time to discharge.

(1) Discconnect the battery for 20 minutes.
(2) Store the keys in a safe place some distance from the vehicle.

The fault is likley to be the the connectors under the seat for the thorax air bag or the occupancy sensor, the official fix is to clean the connection with switch cleaner aerosol or WD40 and if possible re-route the wires to give them more slack but this doesn't work for long. The long term cure is to by-pass the connection or butt solder the wires together.



[Edited on 10/3/10 by britishtrident]


sonic - 10/3/10 at 01:04 PM

Thanks for the replies guy's

Great help as always on here

I will have a look and let you know if i fix it