Airbag light on once again

[rmoconnor41]

I am getting a reoccurrence of the dreaded airbag light.
The specialist has managed to get under the seat several times and then reset the light.
He suggested that if it happened again the seat needs to come out.
Are all the cables under the passenger seat? This car has no passenger airbag.
What should the BMW specialist do to cure this problem permanently?
They are very good at all the mainstream work but perhaps this job is more niche.
Thanks

 

[NZ00Z3]

If you don't have a passengers airbag, then the problem will be with the seat belt tensioner. Sometimes giving the connectors a good clean with contact cleaner fixes he problem. The connector on the tensioner is in line of sight of drink spills down the sides of the seats.

Sometimes the connectors and lead has to be replaced.

 

[rmoconnor41]

If you don't have a passengers airbag, then the problem will be with the seat belt tensioner. Sometimes giving the connectors a good clean with contact cleaner fixes he problem. The connector on the tensioner is in line of sight of drink spills down the sides of the seats.

Sometimes the connectors and lead has to be replaced.

Thanks. Even if I take a look I still need him to reset it.
It seems to happen when I carry a passenger (ok my Mrs)
There are leads visible under (her) seat with white connections which there aren’t anything to do with airbag.
If it is a tensioner is it my seat?

 

[NZ00Z3]

The real way to sort this is for you to get a scanner with BMW software so you can read the trouble codes and rest the light yourself. You may even save a bit of money to go toward fuel.

The Airbag module trouble codes will tell us what really is the problem. Then we can give specific advice.

There are several Options for a scanner with BMW software, but the advice is dependent on the age of your Z3. Read this thread: https://zroadster.org/threads/how-to-scan-early-model-z3s-pre-build-date-03-98.39937/#post-612901

 

[AntStark]

@rmoconnor41 Rich..I can pop round and read/clear the code if you want ?

 

[rmoconnor41]

@rmoconnor41 Rich..I can pop round and read/clear the code if you want ?

Hi Ant. A read of the code would be helpful. Thanks.

 

[Dunkelgrun]

I agree with the expert advice here, you really need a scanner to pinpoint the problem. My light comes on every once in a while, it’s the passenger side connection thing with the red button that says push. I spray some cleaner down there, click it a few times, clear the code and it stays off for a while, then it comes back. It really needs to be replaced, the drivers side one looks to have been replaced right before I bought it.

 

[Brian James]

I had this problem - identified as the driver's seat belt tensioner by reading the code from a Creator 310+ scanner.(Thanks Colb!)
I removed the seat using the instructions given by Pelican parts:

BMW Z3 Front Seat Removing and Buckle Replacement | 1996-2002 | Pelican Parts DIY Maintenance Article

Airbag light on for a seat belt buckle fault? This tech article shows you how to replace the seat belt buckle with easy to follow steps.

www.pelicanparts.com

I cleaned the contacts on the connectors that the tensioner has - one on the tensioner held in place by a cable tie and the other, a purple coloured 2 pin connector that connects to the loom.

I then reconnected the battery, cleared the fault and the light extinguished.

Roll on 4 weeks and the same problem has occurred - with the light coming back on and the scanner saying its the drivers seat belt tensioner.

Anybody got any ideas how to check further - could it be the aforementioned wire that connects the loom to the seat belt tensioner or the tensioner itself. Any way of checking?

 

[colb]

The tensioner will have a spec for electrical resistance off the top of my head can't remember what it should be, will try and have a look for details. The problem you have sounds like the tensioner is faulty likely to be a resistance problem or the underseat wiring, since you have already cleaned and checked the wiring I wold suspect the tensioner. You could put a used replacement in no doubt @spurs fan in a coupe will have one. Just take the old one out and put the replacement in, always disconnect the battery when doing this and any other job on airbags and wiring. Clear the codes with the Creator and see if that solves the reoccuring light.
How to here resistance must be less than 1ohm typically it should measure 0.5 or 0.6 ohms

View: https://www.youtube.com/watch?v=4ZHpPVZKQ6k

 

[Brian James]

First of all, many thanks Colb for the advice - as usual VERY much appreciated
Now taken out the seat and measured as per your instructions and utube.
Using the 200 ohm settin (lowest one) getting a reading of 3.2 when connected as per utube video.
Pls see photos
Help please

 

[Richard29]

Same issue on mine, had it scanned and was bad positive battery cable putting a fault on battery safety cut off. New positive battery cable solved it.

 

[colb]

Well going by the Youtube video it should be less than 1.0ohm so next step would be to put in a replacement unit with the cporrect resistance circa 0.5 - 0.6ohms according to the video. Looks like yours at 3.2ohms is duff.

 

[Brian James]

Thanks guys
@Richard29 can you give further detail ?
@spurs fan in a coupe have PM some photos of the tensioner + cable

 

[Richard29]

Over a year ago now. Had it scanned at pmw chelmaford. After messing with occupancy terminals. Code revealed it was the bst. Following diagnosis the positive cable from battery was degraded enough to give fault so new cable instaloed from fron to back.

 

[Brian James]

Thanks Richard - much appreciated.

 

[Richard29]

Where are you based?
I recommend pmw, they have done work on all of my bmws that i cannot do myself.

 

[colb]

Bad resistance problems on the wiring system throughout the car are always a possibility given the age of our cars and the life they have lived. Green crusty corrossion build up on copper wiring and inside componant plugs and sockets are always worth checking and cleaning when searching for the source of problems. Have seen that battery cable for the pyro connection going bad on previouse posts, it can throw up a code in diagnostics if it becomes a dodgy connection in the system.

 

[Joss]

First of all, many thanks Colb for the advice - as usual VERY much appreciated
Now taken out the seat and measured as per your instructions and utube.
Using the 200 ohm settin (lowest one) getting a reading of 3.2 when connected as per utube video.
Pls see photos
Help please

How much work is it to get these out? Any suggestions on where to source a replacement? ebay looks like a bit of a dice roll to me

 

[Brian James]

It is quite straightforward to access the seat belt tensioner - see the technical advice on :

BMW Z3 Front Seat Removing and Buckle Replacement | 1996-2002 | Pelican Parts DIY Maintenance Article

Airbag light on for a seat belt buckle fault? This tech article shows you how to replace the seat belt buckle with easy to follow steps.

www.pelicanparts.com

Sopers at Lincoln can help with a genuine replacement or @spurs fan in a coupe who can supply a 2nd hand one

 

[Joss]

If you don't have a passengers airbag, then the problem will be with the seat belt tensioner.

Sorry to keep hijacking this thread, but what if I do have a passenger airbag? (I assume that means the door?) it was a couple of weeks back that I read the code iirc it was 06 on a b800 scanner