Code 9440785 Front passenger knee airbag igniter B100E 11 (137) - Short to ground

[Abick]

HI,

Audi A6 C7 2012.

Code 9440785 Front passenger knee airbag igniter B100E 11 (137) - Short to ground

Tried resetting it with Vagcom but fault comes back immediately. Therefore I stripped out the passenger side glovebox to check the connectors. What I have found is that there is actually no knee airbag on this side of the car, there are also no connections present for a knee airbag on this side.

This has obviously left me a bit confused. I have owned the car for nearly a two now with no issues and the fault only started reporting last month for no apparent reason. The fact that there are no airbags fitted in these locations is what is confusing me.

Any advice would be gratefully appreciated.

Thanks

[VAG-Abound]

The implied resolution here from someone who looks like they knew what they were doing was to have a new control unit fitted: question sur codage long VCDS - Page 2 - Tlemcen Car electronics

[Abick]

I really hope that it will do without replacing the airbag module .

[VAG-Abound]

Naturally .

Does VCDS give you a place to remove the detection / test of the airbag, perhaps under "Adaptation" rather than "Coding"?

When I borrowed a friend's full version of VCDS I was able to monitor the resistance that was being reported for each airbag, and use that to work out what resistor I could put in place to suppress the (different) problem I was having. Do you have that version? Although the control unit really ought to believe it is not there it might be easier to play along and pretend it is.

[Abick]

Unfortunately, I don't have the full version of VCDS, so I think I'll have to go to the garage. I understand what you mean, on the Internet, many write that you can put an airbag emulator, but I I do not know what the resistance of the resistor should be. There are only 2 wires on the emulator aliexpress, but I have 3 (brown, black, blue).

[VAG-Abound]

The "emulator" I used to suppress the warning light while waiting for parts to do a proper fix was just a resistor across the two relevant wires.

When you say the airbag is missing have you got as far as looking at the connector which I think is in the front door hinge pillar / footwell side to see what is in which plugs? I presume "missing" means the wires that would go to the airbag are not in the relevant plug there. If they are there but then run off to an empty end-point somewhere else then that does give places to look for the implied electrical short. In other words, where are your brown / black / blue wires - in a small 3-wire connector right behind the glovebox, a ~20 pin connector closer to a pillar, etc?

[aw911]

It don't think this is a fault that can be rectified by a resistor. If the airbag unit (ie knee airbag) isn't even fitted then there is no wiring to that actual model.

I had a similar issue and stripped out so much stuff trying to get to the bottom of it.....I even got the wiring diagram and the correct pins for the airbag control unit and made a resistor to fool the control unit into thinking that it had a knee airbag fitted.....the fault was still apparent after resetting with VCDS.

The only thing that cleared the fault was the car being in my garage for approx 2 weeks while I did some engine work on it....after that the fault went away for approx 2 months.

Lots of people are reporting these short to ground issues on airbag modules that don't exist....I'm not sure if anyone has successfully got to the bottom of it. A new airbag control module fitted and coded by Audi is approx £1000. You cannot fit one out of another Audi A6 due to component protection on these parts.

I wonder if some water ingress or dampness somewhere else is creating an issue that is being detected as a false fault in the airbag module somehow....as I think some other systems feed into it from the audi schematics. Hence why the fault went away after being sat in the garage for 2 weeks.

Maybe a new airbag control module would rectify the issue....but at £1000 its an expensive gamble