Airbag, Dashboard, Seat Belt & Airbag ECU Repairs

[GiveMeABreak]

Diagbox is used by official Citroen dealerships and is always up to date - it is a requirement of the dealership - so that first one you went to can't be an official dealership.

As for the codes, yes, there can be lots of causes for the Airbag ECU to bring up faults which is why a diagnosis is required. Any triggered fault codes should be stored in the log in the ECU, so when read with a proper diagnostic system like Diagbox, the log can be read to show any historic faults.

Common causes can be the wiring that run under floor from the seats / seat belts to the airbag ECU in the central binnacle. But knowing where the fault is can be the issue - and working on the airbag systems can be dangerous, so don't go attaching multimeters or probing without knowing what you are doing or you could trigger an airbag.

Lastly, you need to realise you have a fault on the system for a reason. Until this fault is diagnosed and repaired, no amount of diagnostic machines can make the fault code magically disappear. As soon as the fault is triggered - the warnings will start again.

My advice is to get it to a proper dealer and get them to diagnose and correct the fault for you.

If you have any fault codes already, then do put them up here with your VIN and I can at least see what the fault is indicating.

[Rikon]

My airbag sign has been on wouldn’t ho off.

[dispatch2012]

realise this is an old post. one of the comments mentioned wiring under floor mat right hand drivers side. also, theres fuses in battery well on my dispatch that i cleaned and airbag light went out. i also list other cures for airbag light ive come across on a post i will try to link to here. if i cant link, search my other posts.


viewtopic.php?t=80330

[Huskyxantia]

I to have found other looms under carpets worn then bare wires touch the car body to which all types of lights and fault codes will be triggered, sometimes its worth checking looms under carpets just to see if any part has worn .

[quintet]

My 2005 307 has developed an airbag fault on the passenger side, I've carried out a resistance check from the 4 pin connector under the seat to the 2 pin seat airbag & there doesn't appear to be any issues there so ive ordered an airbag bypass loom & I'll see if that narrows down the fault area by at least ruling out a fault with the passenger seat wiring & seat airbag unit. If the fault remains after fitting the bypass loom i guess the fault will be between the seat connector, airbag ecu & everything in between, if it goes i guess it could actually be the airbag it's self.

Although i think it's unlikely to be related this fault happened 24 hours after the windscreen was replaced, initially the fault was shown as intermittent during the initial diagnostic test but after i fiddled with the seat wiring it's gone to permanent & obviously won't erase.

[quintet]

Has anyone on here used a resistor wiring loom in order to fault diagnose an airbag fault? I was expecting the yellow & orange wires in the female plug to match the yellow and orange wires in the male plug & i was going to connect the resistor loom to the yellow and orange wires in the male plug, however they do not line up with the yellow and orange wires in the female plug.

Male plug -
pin 1- yellow
Pin 2 - blue
Pin 3 - orange
Pin 4 - green (yellow tracer)

Female plug
Pin 1 - yellow
Pin 2 - orange
Pin 3 - not used
Pin 4 - green (yellow tracer)

Because the yellow and orange wires don't match in the plugs im not willing to risk connecting the resistor loom.

Anyone know which wires i should connect the resistor loom to in the male plug? With pin 3 on the female plug not having any wire in it can i presume the orange wire in pin 3 of the male plug is not used as it's apparently not connected to anything.

[quintet]

After having let an auto electrician have a look at my car the passenger seat airbag has failed so now i'm after a replacement matching front passenger seat or possibly just an airbag but they're a pain in the rear to remove/replace.

[quintet]

Testing of a seat air bag, this is actually a spare drivers seat airbag i have.

[quintet]

I removed the (suspect) faulty passenger seat airbag today and found the ohms reading is pretty much the same as the other seat airbags ive tested (around 2.4-//6 ohms) so now im a bit stumped as to why this one was putting the airbag warning light on when it was connected. With the fused bypass wiring loom fitted the warning light stayed off.

[CitroJim]

I've tried to use a substitute standard 10% tolerance carbon film resistor to try and 'fool' an airbag ECU on a Xantia in the past with poor results...

I'm wondering if the ECU is looking for a very precise resistance reading and maybe looking for a bit of inductance too in an attempt to know it's a real airbag it's looking at...

The difference between 2.4 ohms and 2.6 ohms may be just too far out of its range of tolerance.

An interesting experiment would be to take a 2.4 ohm test resistor, a standard value in the E24 series, and choosing one nearest to 2.4 ohms, and see if this makes the ECU happy. The next standard E24 value is 2.7 ohms but you may, in a small batch, find one nearer to 2.6 ohms to confirm your airbag has gone out of ECU tolerance.

Also, many carbon film resistors are spiral wound so have a little inherent inductance and this too may upset the ECU if it's really fussy...

[407]

Hi

on my 407 ES9 I've finally got a Diag fault for the Air bag warning light, being a C613 Rear right satellite or front door fault. Cause Local

I've noticed the Airbag light normally stays off unless there is a bit of rain, and then it triggers but disappears after a few days (sunny weather).

I suspect a dirty connector issue.

So the question is where exactly is the connector (s) that I need to find and clean / fiddle with.

Can I assume

a) the rear right satellite is the airbag in the inner sill pillar area (eg the support between the froint and rear doors) ?

b) the front right door is the airbag in the door rest ?

c) I assume both of these are in series / on the same airbag cable back to the airbag ECU and hence why they are together.

A pic showing the cables / connector locations in the car would be useful (so I only have the break a few clips .

regards

[GiveMeABreak]

Hi

No it's not referring to any of the airbags. The satellite sensor is the acceleration sensor located here at the side floor level behind the trim:

[407]

Thanks Marc (as usual)

So I pulled the seat belt bolt, trim and carpets off only to find the sensor forward of the driver's side pillar (so your diagram is for the passenger side

It helps re access to raise the seat up and move / push it as far forward as you can.

I knew I had a bit of a water leak when it rains , both driver's side front and rear passenger foot wells get damp (Ive tried but failed to find the source) but the spongy carpet was pretty soaked, so I guess the moisture is not helping the connectors.

The sensor itself is a bugger to get to as it low and encased by a black metal shield. I tried to find the clip to release and pull the plug off but failed (ps - its under the plug closest to the floor)

In the end, I resorted to removing the top rivet and bending the shield out of the way a bit as there was no other way to slip it out after removing the bolt.

I clean and reconnected it a few time and then check the air bag warning and it went off. So far so good I thought.

I used a hair dryer on low heat running for a few minutes each time under the carpet to try and remove a bit of the moisture but suspect a few days in the sun would be required (which is probably why the warning comes and goes). That said, it was 37 C here yesterday so I left all the doors open .

Alas, driving back from work today the dreaded air bag light came back on, and then disappeared just as I got home.

So

a) could the sensor itself be the issue - any way to test ?

b) other than cutting out the carpet sponge in that location in the vain hope it might help, any other ideas ? Its sort of hidden bewteen the driver seat and seat belt

c) any ideas where the water leak might becoming from ? Seals look fine, no obvious water trails (but I have yet to used the talc powder trick)

ps - seem like they could have mounted it in the small space just below the seat belt coiler (eg inside the pillar itself) which would have lifted it up off the floor but maybe caused other issues.

cheers

[CitroJim]

On the wet issue, I'd bite the bullet - as I have many times on soggy Xantias - and remove all the carpets and let them dry fully in the sun. They won't ever do so whilst in position.

I know it's a lot of work but worth it.

I'd do the same with that sensor. Remove it and leave it in a warm place for several days to properly and fully dry out.

Then replace it and run around in the car with no carpets fitted for a few days to see if the problem is fully resolved.

[GiveMeABreak]

I agree with Jim, you may have an issue with ongoing damp in that area that may well have caused the internal sensor components to become corroded from moisture ingress.