Hi all. My Cat C that was finished has just thrown up an Airbag error and MES throws up a resistance error on the drivers pre tensioner, which I have changed for a used one.

I've run a ampage check on MES and the passenger one which is OK is 2 Ohms and the drivers is 7 Ohms which is obviously throwing up the error and airbag light.

My question is, does any of you very clever people out there know whether this is likely to be an error with the pre-tensioner itself or within the wiring somewhere?

It's a real pain because to remove it, you have to take out the rear seats and side panel again. Grrrr

Thank you as always.

If the pretensioner is pyrotechnic it'd be unusual for it to fail to such a value IMHO. More likely a slightly duff connection I'd expect.

I have to take the seats out to get to it anyway, but I’ll have a look at the wires just in case, cheers.

As you've sourced a used one, there could be differences. Check any labels.
Used one could be 'used', so no good. Was it available because it was from a crashed car? What is the resistance of the one you removed?

portland_bill said:

As you've sourced a used one, there could be differences. Check any labels.
Used one could be 'used', so no good. Was it available because it was from a crashed car? What is the resistance of the one you removed?

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I always buy used non deployed ones. Never had a problem. Think I’ve thrown the deployed one but might have an old one knocking around somewhere. I buy seatbelts and pretensioners together all the time.

Hi, did you get to the bottom of this problem in the end?
Ive got exactly the same situation now

I can’t actually remember as it was a couple of years ago but from memory I think I got another one. Just because the cable isn’t retracted doesn’t necessarily mean it’s a good one. I certainly didn’t do anything with the wiring so it must have been the thing itself.

Incidentally I’ve just changed both seatbelts and pretensioners on my Abarth without removing the seat backs. I thought i would give it a go as I already had the seat pad out. There’s just enough room to get a socket wrench in. Only tricky but was bending the quarter panel to get the braided wire into the slot once the new pretensioner was in.

Thanks for the reply
For the record my story is i fixed up a Cat N with v/light frontal damage, sorted all the bodywork and as the driver and passenger pretensioners had activated i replaced both sides (and seatbelts) with used parts thinking that would suffice.
When the airbag fault on the dash remained i then sent the airbag ECU away to have it cleared........ but the dash fault remained
When i tested with MES i got the same readings as you did, so i replaced the drivers side pretensioner again.... no difference to "resistance" readings at all?
Ive checked all the connections countless times and even replaced the "crash impact sensor".... no result?
So now ive had to bite the bullet and get an auto electrician to have a look tommorow.
All thats stopping me getting an MOT and on the road is this bloody dash fault!!...

Hmmm, sometimes when you send ecus to be reset, all they reset is by deleting the crash data file. You sometimes need to reset the actual codes yourself. Sometimes they just go, sometimes you have to clear them.

Are you sure it’s the pretensioner and not the seatbelt?

The MES is showing the same fault as yours did "driver pretensioner resistance 7ohm"
Ive tried resetting/clearing with MES but as the fault is apparently still there it wont clear?

You could try putting a resistor into the plug going to the car not the one in the pretensioner, one wire in each hole and see if it goes. That would rule out the pretensioner and the plug.

Just had the auto electrician round with his "snap on" diagnostics, had a swap around of some bits and used a resistor like you said, he reckons the drivers side belt and pretensioner is still faulty? Looks like i somehow got f**ked units from breakers?
My options now are source another set or use my daughters parts off her twinair and see if that works........

You can put a resistor in the belt plug too, that will eliminate it.

RESULT!!!
After all that it was actually the seat belt that is faulty, i simply unplugged and replaced with a 2.2 ohm resistor, cleared the faults with MES and dashboard now fault free!

Thanks for input, appreciated the feedback

plugandplay said:

RESULT!!!
After all that it was actually the seat belt that is faulty, i simply unplugged and replaced with a 2.2 ohm resistor, cleared the faults with MES and dashboard now fault free!

Thanks for input, appreciated the feedback

Click to expand...

Excellent thought as much.

UPDATE!!

Booked in for MOT, jumped in car a few days after clearing faults etc and the bloody "airbag fault" is back on dash ffs!? :bang:



I plugged in MES and BO123-1B drivers abdominal pretensioner error code is back?

It wont clear now but i dont understand why the resistances are still all within limits (2-2.5 ohms)??

HELP!...........

Has the resistor come loose.

Ive not checked but i doubt it, the car hasnt turned a wheel since last week when i did it?

That was my first thought but if that was the case, the resistance would have surely gone back up to 7ohms, its still reading correct at 2.2?.....

Im thinking of replacing the seatbelt unit (again), realistically it needs doing anyway to put it right i suppose.....