Car airbag diagnostic code reader.

[premmington]

On the B5 Audi / Passats seat airbag monitoring on the drivers seat is disrupted by damaged cables, damaged due to regular movement of the seat. There was an Audi service bulletin (ref. VCDS Wiki ) saying to disconnect the seat wiring and fit a 2.4 ohm resistor to the now empty plug so the car can see the phantom seat air bag. The bulletin had a pdf for the customer to sign acknowledging the work had been done, stating that the car had been homologated both with and without the side air bag.
Obviously you would not do this to a driver or passenger airbag but it holds up @premmington 's observations that the diagnostics are looking for 2.2 to 3.3 ohm.

Someone would if they wanted an MOT for a sales car that had just sold for big money

 

[zx9]

To clarify - the OHM rating I stated is for airbag detonators - they are fairly universal.

Seat mats are a differing thing - I normally measure the other good seat to get a referance resistance.

It was the seat side airbags referred to in the bulletin and indeed in my A4 which is how I found it.

 

[Wightsparks]

So in summary don't go testing your airbag's resistance with your standard meter that takes a 9v battery!
else ....

 

[jimbo84]

Well it didn't last, airbag light coming on and off intermittently after a week and now it's back on constantly. Local scrappies have an i20 in but bags have gone off so they wouldn't sell me the clock spring. Genuine one from the dealers £102+vat, ruled out the ebay scrap yards and chinese knock offs with it being a safety part but debating a new german one that looks half decent for less than half the price of the dealers.

 

[premmington]

Well it didn't last, airbag light coming on and off intermittently after a week and now it's back on constantly. Local scrappies have an i20 in but bags have gone off so they wouldn't sell me the clock spring. Genuine one from the dealers £102+vat, ruled out the ebay scrap yards and chinese knock offs with it being a safety part but debating a new german one that looks half decent for less than half the price of the dealers.

Sometimes you have to bite the bullet... £102 + VAT does not sound too bad. Last week I paid £400 + for a genuine Skoda one (and that was a pig to fit).

 

[jimbo84]

Sometimes you have to bite the bullet... £102 + VAT does not sound too bad. Last week I paid £400 + for a genuine Skoda one (and that was a pig to fit).

Gone for a german knock off, £50 delivered, will see how that goes. At least they're an easy fit on this car.

 

[jimbo84]

A little update incase anybody is interested,

The German ebay part arrived, didn't look too bad. Went to fit, on clipping to the steering column one of the plastic clips snapped off (for reference the original one has been on and off a good few times no bother). There are two plugs on it, one for the airbag one for the horn, the one for the horn didn't fit or engage properly. The airbag light was still on, on testing resistance of the new clock spring I found the shorting pins didn't actually short the terminals. All in all a pretty poor part.

Having doubt in my mind I got a local auto electrician to diagnose for me and he confirmed it was the clock spring.

Ordered from the dealer which was a superseded part and the new one was £195 with the vat I've fitted it this afternoon and it has cured the fault, happy days at last.

Currently trying to get my money back from the ebay seller.

A textbook case of buy cheap buy twice.