E36 Airbag Light

[abels]

Morning all. This morning I took my E36 328i Cabrio for the Swiss equivalent of an MOT. The car passsed on everything except that the Airbag light is showing on the dash (something that only came on driving to the test centre).
Does anybody know what causes this? Is it something you can simply reset or is it a bit more than that?
I would be grateful for any advice as I have to take it back in the next 3 weeks.

Cheers

[Mroad]

I would say the most common cause is the seat belt pretensioner wiring. You adjust the seat, it pulls the wire causing a temporary break in the circuit and the air bag light goes on....and stays on.
It can only be reset with a proper reset tool such as the Peake R5/SRS http://www.peakeresearch.com/srstool.htm
However it's cheaper to find a friendly dealer or specialist who can not only reset the light but read the error codes to confirm what's wrong.

[paoloh]

I have a weird issue with an e36 compact, the airbag light is on, checked OBD for faults, there are none, so took dash out to investigate and there isn't even a bulb in the airbag hole but the airbag light is constantly dimly lit.

Any ideas?

[abels]

Mroad said:

I would say the most common cause is the seat belt pretensioner wiring. You adjust the seat, it pulls the wire causing a temporary break in the circuit and the air bag light goes on....and stays on.
It can only be reset with a proper reset tool such as the Peake R5/SRS http://www.peakeresearch.com/srstool.htm
However it's cheaper to find a friendly dealer or specialist who can not only reset the light but read the error codes to confirm what's wrong.

Thanks, I think I will try and take it to my local garage later today.

[Mroad]

paoloh said:

I have a weird issue with an e36 compact, the airbag light is on, checked OBD for faults, there are none, so took dash out to investigate and there isn't even a bulb in the airbag hole but the airbag light is constantly dimly lit.

Any ideas?

A standard OBD tool may not read SRS faults as it is a completely separate ECU (in the E36 the SRS ECU is under the back seat). In the case of the Peake tools you need a separate SRS reader/reset tool, the standard fault code reader/reset tool won't see it. Make sure your OBD tool can actually read SRS codes.

It may seem a stupid question but does the car actually have airbags/SRS?
The dashes are standardised, it may have an SRS warning on it but not actually have a bulb inserted if no airbags etc. are fitted.
If it does have SRS has the bulb and wiring fallen out the back and sitting behind the dash? It's possible when you put the dash back the bulb stuck behind the dash is shining dimly through the empty hole, either that or if there's no SRS another bulb nearby is illuminating it indirectly.
If there's no SRS then a bit of black tape across the back of the hole should sort it.

Edited by Mroad on Tuesday 8th September 19:46

[TheEnd]

Mroad said:

paoloh said:

I have a weird issue with an e36 compact, the airbag light is on, checked OBD for faults, there are none, so took dash out to investigate and there isn't even a bulb in the airbag hole but the airbag light is constantly dimly lit.

Any ideas?

A standard OBD tool may not read SRS faults as it is a completely separate ECU (in the E36 the SRS ECU is under the back seat). In the case of the Peake tools you need a separate SRS reader/reset tool, the standard fault code reader/reset tool won't see it. Make sure your OBD tool can actually read SRS codes.

It may seem a stupid question but does the car actually have airbags/SRS?
The dashes are standardised, it may have an SRS warning on it but not actually have a bulb inserted if no airbags etc. are fitted.
If it does have SRS has the bulb and wiring fallen out the back and sitting behind the dash? It's possible when you put the dash back the bulb stuck behind the dash is shining dimly through the empty hole, either that or if there's no SRS another bulb nearby is illuminating it indirectly.
If there's no SRS then a bit of black tape across the back of the hole should sort it.

Edited by Mroad on Tuesday 8th September 19:46

It's way cleverer than that!
One of the things it checks in the SRS system is the SRS warning light. If that has blown, or been removed, it lights an LED instead.

[Mroad]

TheEnd said:

Mroad said:

paoloh said:

I have a weird issue with an e36 compact, the airbag light is on, checked OBD for faults, there are none, so took dash out to investigate and there isn't even a bulb in the airbag hole but the airbag light is constantly dimly lit.

Any ideas?

A standard OBD tool may not read SRS faults as it is a completely separate ECU (in the E36 the SRS ECU is under the back seat). In the case of the Peake tools you need a separate SRS reader/reset tool, the standard fault code reader/reset tool won't see it. Make sure your OBD tool can actually read SRS codes.

It may seem a stupid question but does the car actually have airbags/SRS?
The dashes are standardised, it may have an SRS warning on it but not actually have a bulb inserted if no airbags etc. are fitted.
If it does have SRS has the bulb and wiring fallen out the back and sitting behind the dash? It's possible when you put the dash back the bulb stuck behind the dash is shining dimly through the empty hole, either that or if there's no SRS another bulb nearby is illuminating it indirectly.
If there's no SRS then a bit of black tape across the back of the hole should sort it.

Edited by Mroad on Tuesday 8th September 19:46

It's way cleverer than that!
One of the things it checks in the SRS system is the SRS warning light. If that has blown, or been removed, it lights an LED instead.

A warning light for a warning light! I never knew that, good call...what if the LED goes though?
Could well be the problem then, it's missing a bulb. Trouble is you have wonder why it's missing a bulb, could be someone was trying to hide an expensive fault.

[TheEnd]

I'd imagine it is the usual pretensioner wiring on the passenger seat.
When the seats moves, if it breaks contact for a split second, the light is on and it stays on..

No airbag isn't an MOT fail, but i guess a previous owner removed the bulb to attempt to hide it.

E46s are a little more lenient, they will often switch off the light if things are OK, but e36s keep the light on until reset for whatever reason.

[abels]

Hi all, thanks for all the feedback. As mentioned a couple of times on this thread, it was an issue with the pretensioner on the passenger side. All working now and passed the Swiss equivalent of the MOT this morning.

Thanks again