Seatbelt pre-tensioner (Xsara)

[RichardW]

My Sister's 02 Xsara failed MOT on side air bag light. Garage interrogated it and pointed finger at the pre-tensioner. Ah! connectors under the seat says I; Nooo says the garage, we've tried that, it's the pre-tensioner unit. Said they could get a new unit from Citroen for £156 + hour's labour to fit. The bay turned up one for £45 delivered and I offered to fit it. Now, I've NEVER heard of one of these giving trouble - and it seems to be the same unit fitted to some Xantias and XMs. Anyone else heard of a failure? Anyone changed one and got any tips? I can't imagine it's too difficult - seat out, change unit, seat back in unless it's got a big spring in it somewhere that needs to be compressed Fault was apparently reported as short to earth, and she said it was worse when wet, so I'm rather thinking the wire is chafed through. Anyway, we shall see.

[wheeler]

Do you mean the actual side airbag ? cant imagine a seatbelt pre tensioner would cause the side airbag light to come on ??

[RichardW]

Dunno - working third hand - garage definitely fingered the stalk unit. Perhaps it was the main airbag light - I had trouble with the main airbag light on my Xantia, and it was the connectors under the drivers seat - presumably to the stalk unit. If fiddling with the connections and changing the unit doesn't fix it, then I will have to talk nicely to Mandrake (again ) and get it on his Lexia for more delving.

I hope that it's not a cable fault under the carpet somewhere

[wheeler]

I would remove both of them & swap them over (just plug them in as they obviously won't fit on opposite sides) then see if the fault changes to the other side before forking out for a new one. Can't say I've ever had to change a per tensioner for bringing the airbag light on unless it has been deployed.

[RichardW]

Changed it.... air bag light still resolutely on Assuming that the fault was ID'd correctly does it need to go back on the computer to be re-set? Tried taking the battery off more in hope than anything, but that also drew a blank. Personally my money is on the COM2000 as there are also some issues with the indicators and headlights. Wish she'd told me before she took it off to get it tested, then we'd have had time to do something about it

[wheeler]

Assuming that the fault was ID'd correctly does it need to go back on the computer to be re-set?

No, if you cured the problem the light would have went out itself although the fault code would still remain I the memory if you read it. Did the garage say what the fault code was ?
Also can't remember if this is the same for xsaras but on the saxo Lexia id's the drivers side on a RHD model as seat belt 2 & the passengers side as seatbelt 1 which can be confusing, obviously due to it being geared towards a LHD car.

[Mandrake]

Assuming that the fault was ID'd correctly does it need to go back on the computer to be re-set?

No, if you cured the problem the light would have went out itself although the fault code would still remain I the memory if you read it. Did the garage say what the fault code was ?
Also can't remember if this is the same for xsaras but on the saxo Lexia id's the drivers side on a RHD model as seat belt 2 & the passengers side as seatbelt 1 which can be confusing, obviously due to it being geared towards a LHD car.

I noticed the same thing on my Xantia when interrogating the status of the door switches from the CPH - front left and right doors are identified back to front! Presumably due to being designed with LHD in mind, and a sloppy translation to English. (Translating drivers door to left hand door for example, only valid for LHD!) Confusing if you're not aware of it! Could the garage be looking for the fault on the wrong side due to mislabelling of left and right in the Lexia ?

[RichardW]

It now has a ticket and an air bag light Garage stuck their tool on it and re set the light, and it went out, and stayed out for a few re-starts. Ticket printed, bill paid, go to drive away - light back on! So more investigation required, but at least the MOT pressure is off!

[Mandrake]

Shhhhh!! Don't let Mike see this one...

[RichardW]

Had it on lexia today - current fault is short circuit to driver's air bag, so I guess that means new Com2000 required No idea if the actual fault was ever the pre-tensioner, or if they just misread the code Citroen price for the Com2000 is £377

[Mandrake]

Surely its worth checking the wiring with a multimeter though ? If you can unplug it at both ends so the air bag is not connected you could do a continuity check and also check for shorts from the wiring to earth... I certainly would before spending £377