Strange airbag warning fault code

[Rick-sta]

I had a customer's car in and noticed the airbag light was covered up when I dismantled his instrument cluster. Informed the owner who wasn't aware. Uncovered the airbag light and after reinstalling the cluster to the car as expected we found the airbag warning light stays on.

Thought this would be the usual under seat connectors but thought I'd check the fault code on toaf first. This is the fault code that came up:

"863 - Airbag-light control -break/shor to ground"

Any ideas what the issue could be ? I've never come across this one before.

Cheers
Rick

[YorkshireDave]

I had a similar issue with a ‘short to ground’ message on my E46 which the ZT-T replaced.
It took a while to trace as it could have been any kind of issue in the airbag circuit that causes the loop to stay open.
The light went out after replacing the steering wheel and airbag with another as they had both looked very worn after nearly 200k miles and I thought it was worth a try.

Dave

[cb750chris]

I would suspect somebody has cut the wire between the airbag module and the ipk to try and turn the light off, before covering the lamp up.
Check the wires by the airbag module, and the ipk

[Rick-sta]

Originally Posted by cb750chris

I would suspect somebody has cut the wire between the airbag module and the ipk to try and turn the light off, before covering the lamp up.
Check the wires by the airbag module, and the ipk

That's what I thought but the all the wiring at the IPK end seems fine, couldn't find any cut wires there and all the original tape is still around the looms there. Tried to look at the wiring for the airbag ECU under the center console but was impossible to see any of it at all without removing the center console.

Would a t4 bring up a better diagnosis of what it could be than the code I'm getting on toaf?

[SD1too]

Originally Posted by Rick-sta

Would a t4 bring up a better diagnosis of what it could be than the code I'm getting on toaf?

Originally Posted by Rick-sta

"863 - Airbag-light control -break/shor to ground"

Hi Rick,

I had an airbag fault a few years ago which Phil_T4 successfully traced.

The problem with your current TOAF description is that it's too unspecific to be helpful. A "break" and "short to ground" are opposite fault conditions! We need to know which of those two it is.

A "break" could be loss of the power supply to one of the SRS components. You can check those with a multimeter. Similarly it could be a poor earth. If nothing is revealed with that, move on to the possibility of a short circuit. Disconnect the bags and sensors one by one, re-testing with TOAF after each disconnection. When (or if) the warning light extinguishes you've found the area to investigate closely using conventional methods.

In my case a supply wire had been crushed against a sharp earth terminal in the passenger front footwell which had punctured the wire and caused a short circuit.

Be prepared to release the centre centre console to gain access to the DCU (as it's called ).

Simon