A8 Parts Forum - Airbag warning light

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- - Airbag warning light - Passenger seat (https://forum.a8parts.co.uk/showthread.php?t=114)

Cheers guys

I've just done the closed loop blue and white wire airbag light off fix. Perfect. :cool:

Check in VCDS that the sensor reads 'seat occupied'. Otherwise if you have a passenger with you their airbag will be switched off. God forbid.
The resistance value has been checked by others before, you need a 470 Ohm resistor or there abouts.

http://forum.a8parts.co.uk/attachmen...1&d=1507282055

just another twist that could be noticed with global warning !

despite having used andrew's fix of isolating the front sensor have been having a problem of light staying on when car left in the sun ; then stays off when the car is cool

found someones comment about getting the problem when seat heater is on full and the penny dropped ....with the excessive temperatures we have been having this summer the sensor is changing value when blasted by the sun on the seat ... has never happened when the car is left in the shade !

thigh pad isolated all ok ,but light stayed on when overheated in the sun
latest twist .......winter arrived , seat heaters on full with both front seats occupied ...no problem
supermarket car park , someone parked too close to allow opening of passenger side doors ; swmbo therefore jumps in the back ; light now stays on ! after 10 miles turn off passenger seat heater ; another 10 miles light goes out , so maybe a posterior is needed to absorb some of the heat !
so where does the seat temperature come into this ?

Quote:

Originally Posted by HPsauce (Post 43243)

OK, this is the EVEN CHEAPER FIX, cost effectively nil if it is just the thigh pad sensor at fault! +++

Move the seat back and tilt the front up to gain access. Move the thigh support forwards as far as it will go.
Look underneath and you'll see a thin black cable sleeve that runs from the thigh support back under the seat, remove the cable tie to ease access.

Carefully cut open the sleeve open to confirm it contains the blue and white pair of wires for the occupancy sensor; trim back the sleeve to bare a good length of wire and cut through it nearer where it enters the pad so there's a decent length to work on emerging from under the rear of the seat.

Tape up or cable tie the spare wires going into the thigh pad, this part of the sensor is now inactive. Move the pad back now to make access easier.
Join the blue and white wires together at the end of the cable coming from under the seat.
I actually used a "choc-block" connector and small loop of wire, but that was for convenience of testing resistances. You could just strip off some insulation and crimp them together.
(I'll probably do that some time if the fix continues to work OK)
Tape or cable-tie out of the way and return seat to normal position.

Finally plug in your laptop running VCDS (or equivalent) and clear the codes from the Airbag Module.

All seems to be working normally so far...... :D

I did do some vague resistance testing, as follows:
The thigh pad was open circuit when unloaded, pressed as hard as I could manage (in some places) I could get it down to maybe 20K ohms.
The main seat pad was in the "several K ohms" range when unloaded and dropped to maybe 200 ohms (IIRC, not sure exactly what range my meter was on) with my big fat backside on it. :o

I'll report back if there are any untoward developments.....:o

I tried this hack but my light remains on.

The only difference is I did it further down the line nearer to the brown connector. Could that be why?

I’ve circled the connector I assume was the right one to follow from Ian’s initial post.

Evening all, is anyone able to confirm my previous post before I start rooting around again.

Quote:

Originally Posted by RICKY D (Post 174571)

Evening all, is anyone able to confirm my previous post before I start rooting around again.

Read through IT's post and also the one you quoted from HPsauce, as well as the post by Goran above (#102) with the photo. Since they're all referencing the blue and white wires, and you 'tried this hack', is it possible that the resistor you used is faulty, or not attached properly, depending on how you achieved it? Terrible thought, and I'm sorry to ask, but did you try clearing the code, as you don't mention it specifically? i.e. "I tried clearing the code, but it wouldn't".

No offence taken….its a valid question seeing as I didn’t mention it :D

To confirm, yes the garage “cleared” the code but it came straight back. The error was with the occupancy sensor so we’re comfortable it’s not another airbag issue.

Also, just to clarify I actually did Andrew’s “even cheaper fix” as I ordered a 470 kohm resistor instead of 470 ohm :rolleyes:

I’m going to try again and take it back to the garage next week when he has time to investigate. +++

I think if you read through my earlier comments I also did a resistance check on both seat pads, occupied and unoccupied.
Definitely worth doing. +++
(IIRC they are normally wired in series.)

Ah yes, I’ve just re-read Andrew +++

Thanks :)