Hello everyone, I’m new to the forum but have known about it for years as my dad is on here and has been for a while.

 

I need some help with an airbag light and am at a loss of what to do so any help would be appreciated. I bought my car (mk1 fabia vRS) with airbag light on, seller told me it came on randomly when driving (bs I think). Ran diagnostics codes, it said it was sensor so that was replaced but light still on. Then called an auto electrician to have a look and tested wiring and said it was fine so said it was either the airbag ecu or sensor so changed ecu. Still same codes. Changed sensor back again (in case it was faulty) but no change. Then saw ecu had a ‘K’ on the end of the part number so got sensor with ‘K’ on it as the previous 2 didn’t. Plugged in and got fault codes passenger side (have attached pictures of faults with new ecu). Then changed back to original ecu and got fault codes drivers side (also attached) Plus added code of seatbelt igniter. When I clear the codes they just come straight back. 

It seems to be the ecu stores codes as the faults changed when putting a different ecu in ? Can it be cleared and reprogrammed? Anyone able to help as mot is coming up? 

 

I don’t know much about electronics so if anyone is around Hertfordshire or knows anywhere I can take it near me that would help

Thanks in advance

Looks to me like the ECU you bought may be for a LHD car, so it thinks right side is passenger side? Always best to stick to exact part number matches including suffix, unless you have concrete information as to compatibility.

 

You should be able to clear airbag faults with VCDS (including the freeware version VCDS Lite, which you can download from ross-tech.com). Then a cheap (<£20) KKL cable to connect car to laptop and you have tip-top diagnostic capabilities. You'll have to find and fix the problems first though, which I would hazard a guess as being corroded wiring connections.  

 

 

Edited 18 July, 20232 yr by Breezy_Pete

Thank you, the ECU was exactly the same part number and index (08) as the original. Surely if the ECU was from a LHD car then the belt tensioner fault would would have swapped sides aswell? Re the corroded connections, do you mean the connector block to the ECU and/or the sensor? Would I be able to see the corrosion?

Sorry, must have looked too quickly, as I thought I'd seen both faults swapping sides.

 

No idea what connectors there are peripherally, but I think the airbag ECU is pretty unlikely to get damp in its location, so start at crash sensor and seatbelt reel.  Where is the relevant crash sensor?

 

Water ingress tend to leave green crusty corrosion products on copper wire and connector pins.

4 minutes ago, Breezy_Pete said:

Where is the relevant crash sensor?

 

On the crossmember under the front seats I think.

 

https://workshop-manuals.com/skoda/fabia-mk1/body/body_work/passenger_protection/airbag/airbag_system/?expand_article=1

@Breezy_Petethank you. Airbag sensor is explain here in a previous post from my dad that I believe you helped with: 

 

this is the same problem we are still trying to deal with but will look for any corrosion

I'll look at the circuits shortly.  I wonder if these items share an earth, spliced into the main cabin loom somewhere that might get damp...

It seems not.

Hmm. 

Any history of trouble with heater matrix leaking? That's immediately above the airbag ECU.

Not that I’m aware of. Only had that car about 9 months. We’re going to have a look at cleaning the connectors and see if that does anything and try remedy the belt tensioner

The usual problem is the underseat connectors (colour bright yellow) being kicked by rear seat passengers, many people solder them, there is also another connector tucked up in the seat squab foam.

I had error 0654 pop up a while ago. This was drivers side belt tensioner.

 

I popped off the b-pillar trim, cleaned the electrical connection (yellow one) at the base which cleared it.

 

Can't remember if it needed clearing with VCDS but as I have a copy I probably did use it to clear it. Ross-Tech says:

• When "Short to positive" or "Short to ground" is found, DO NOT CLEAR THE DTC. This can cause the tensioner to deploy. See repair manual for more information.

Looks like yours is resistance too high so you should be ok. Worth cleaning the connectors as a first step.

 

My car has the side airbag option which was quite rare. No idea if this makes a difference to the side airbag sensor for the seatbelt? 

 

The Fabia can be a bit sensitive to slightly loose/dirty/corroded connections. I had a problem for years where my bulb out light would come on. No one could fix it but I cleaned the Xenon self leveling sensor connection & it cleared.