The airbag light has been on in my MK2 punto since I bought the thing the best part of 3 years ago now. I'd rather not have to scrap the poor thing as now the exhaust is properly fitted and not blowing, it sounds lovely. Nippy little car as I'm sure you'll know.

It was taken to fiat at the time, who stated it needed a new ECU. I recently took it to a local italian specialist who also came back with it needing a new ECU. I have since requested their reasoning for this conclusion as I realised I hadn't actually been given the readout from the diagnostic when I got home.

I'm aware that there is a separate ECU for the airbag, unless I'm mistaken. My question is it likely to be the airbag ECU which needs replacing or is it the main ECU.

If it's the main ECU, as a last resort I'm probably going to chance my luck with a "plug and play" ECU for £80 or so and a set of new ignition coils. Has anyone used these before, or had any success ?

I'm not looking to spend more than £100, as the car isn't exactly worth much as it is.

Thanks.

ecu is on the transmission tunnel next to clutch pedal
it has nothing to do with the main ecu
theres one on ebay to bid now for £15 just make sure the numbers match yours
remember also to disconnect the battery before replacing it
its plug and play if thats your problem
undo both kick panels pull of the silly clips and its 3 10mm nuts

So it is the airbag ECU, not the main one. That's that question solved.

If I can find one where the number match mine, is it just a case of swapping them over ?

get it diagnosed and the fault code cleared

It's been diagnosed twice, by separate companies, as requiring a new ECU.

Numbers should be on the outer casing of your ecu the reason you'll want to match the numbers to a new unit is so you don't cause your self any further problems such as trying to fit one from with side airbags which your car doesn't have.

Also when swapping them over make sure to check and double check that every thing is ok and connected properly to minimise your chance of having to pay for someone to clear a self induced fault code

Finally and very importantly PLEASE! Make sure you disconnect the battery! It has been mentioned but it can't be stressed enough last thing anyone wants is an airbag going off in there face uncontrolled they can kill !

What is the best way to deal with the battery in this case ?

Was going to disconnect it and remove it out of the car. Want to charge the thing anyway.

Do I then leave it for a while ? Or do you touch the two cables to remove the excess electricity ?

Then once there is no power, remove the old ecu. Replace with the new one. Plugged in properly etc.. Then reconnect power ?

If you want to charge it take it out of the way completely

Leave the car an hour then, touching cables together will do nothing for the airbag system it is reverse current protected so as to still be able to function if the electrical systems of the car are destroyed before its had a chance to deploy the bags

Just still be vigilant connecting and disconnecting things common sense stuff like not putting yourself in front of the bag don't let your mates sit in the passenger seat etc

Better to be overly cautious with these things evenif someone else does tell you it's nonsense, it's very hard to say 'I told you so' when you're missing your head

Is there anything that can be done to check that the electrics are clear / safe ? Is running the radio / heater going to do anything helpful? Would rather be sure.

nope non of that will help

just play it safe as suggested and leave it a good hour and you should be ok.

if you folllow the instuctions given its like changing a bulb
the connector on the ecu has a safety clip and then the bracket pulls the clip from the ecu

a 5 year old can do it

Leave it an hour, then unplug the ECU..

I'm going to check the number and then order one this evening. So chances are wont be able to do it until next week.

Well, it was just my luck that the code on my one wasn't the one which seems to be fairly common and easy to source. Luckily found one on eBay, for a whole £13. So snapped that up and will just have to wait and see. Really hope this works.

Out of interest, what would happen if the codes weren't a match ? Does it just trigger the warning light ?

smithmr8 said:

Well, it was just my luck that the code on my one wasn't the one which seems to be fairly common and easy to source. Luckily found one on eBay, for a whole £13. So snapped that up and will just have to wait and see. Really hope this works.

Out of interest, what would happen if the codes weren't a match ? Does it just trigger the warning light ?

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stand well back if you want to find out
personally if the numbers dont match then i wouldnt go there because life is a lottery

http://www.ebay.co.uk/itm/260930610833?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

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Chances are it just wouldn't work, they monitor the bags passively so unlikely to false deploy but I wouldn't rule it out in any case you wouldn't get rid of the airbag light.

Fair enough. The number I needed was: 46806592

Just have to keep my fingers crossed. Would be nice to get the ol' boy MOT'd and keep it on the road a few more years. Lovely little car.

how many airbags have you got?

It's a basic Mia model, so just the one.

smithmr8 said:

It's a basic Mia model, so just the one.

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ones i have have a different number to yours so might be a struggle to match
the one on the bay is dear at £40 ive seen them for £15 and i would get one from a breaker for a £10 if i know the owner