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Technical Airbag - Front Crash sensor

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Technical Airbag - Front Crash sensor

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Twincam1986

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Since I've owned this Stilo, the airbag light has been on. I've never been able to connect to the airbag ECU with FES as it could never detect it being present, so I suspected the ECU was dead.

I recently had this checked at Fiat who confirmed that the ECU was faulty and gave me a price of just over £500 for a new one!

Obviously I'm not paying that as it's about half the car's value, so I sourced one second hand (made sure it was the same part number). I've just fitted it and finally managed to connect to it and read the codes. The only one coming up is 03 Front Crash Sensor - Plausabilty - present. It remains after clearing it and says that it's present.

So at first I presumed I would need a new cras sensor, but before I do that, would it be possible that the donor car suffered a front impact and this has been stored in the ECU, as I've heard this can't be cleared through normal means?

If so, how can I test my front crash sensor?
 
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Don't know about the stilo, but all the cars I have ever bought damaged or with the airbags having went off will need the sensor replaced, my Brera was hit at the front and needed the sensor , ecu, airbag on steering wheel , drivers kneebag , and full dash change for passenger bag, steering wheel ribbon also seatbelts had fired so I would say sensor needs replaced.
Also heard that people have had problems with Can errors when soldering on new airbag plugs that have melted, I have never had a problem doing this though, airbag and SRS systems can be a total pain in the rssse
 
As far as I know, the airbags in my car have never gone off. I was just thinking that if the donor car has had a front impact, it could have stored this in the ECU and that's the code I'm getting. Just trying to go through every option before spending another £100 to turn this sodding light off.

Although I've just contacted the guy I got the ECU from and he said that car had't had a front impact.

It's the fact the FES scan says 'probablity' - as if it thinks it's the crash sensor, but not quite sure :)
 
I have no idea how to clear crash data from an airbag ecu, but if the sensor has been activated it will need changed, with SRS It's a can of worms, I always found if a sensors activated then it's junk, any part of a airbag system goes off you usually need to replace it. But as shadey mentions, I have seen airbags and seatbelts changed on crash damaged cars and the light still coming on until the sensor is changed, then when the airbag system does its pre start check and finds the sensors within the allowed parameters, the light goes out, usually if the sensor goes off I think you get a high or low resistance fault, as I said can be a expensive fix.
 
Shadeyman said:
Airbag error codes can be deleted. If what caused the error has been repaired the error will not re-appear.

I replaced @fender mender crash sensor and cleared the error codes.

FiatECUScan(now called MultiECUScan) will tell you if the crash sensor is faulty(I think). What fault code are you getting?
Click to expand...


03 - Front crash sensor - probability - present - 115

Looks like I'll be changing the crash sensor then.
 
I'm using FES. I don't remember it beginning with a P, but it may have done. I haven't got the full version so I have to write down whatever comes up - I only jotted it down quickly. But that's definitely what the rest of it said.
 
Was the airbag light on when you bought the car, if not and you have not been in an accident, I can't see how the sensor is the problem, usually the ecu stores the data from a sensor which has been activated, I would not be buying anymore unless I was sur that your donor ecu was not taken from an accident damaged car, could you not possibly go and see the guy who sold the ecu to you and see if he has the sensor to match it, if he is selling the ecu he would obviously have bags and belts etc to match it, I know if I was bustin a car with a SRS system which was working, I would take the lot, if he is confident the ecu is ok he should have the sensor and be willing to try it on a pay if it's okay basis, also just have a wee check at the crash sensors plug to see its seated properly.
 
Yes it was on before I bought the car.

I bought the ECU off ebay. I emailed to ask if the car it came from had been in a front impact, he said it hadn't. Obviously I can't prove that.

If the sensor isn't working properly, then it won't send the correct signal to the ECU so surely that's how it would be a problem?

I've already unplugged the sensor and sprayed it with contatc cleaner but it didn't work.
 
Would say the sensor definetly, but just watch out you could end up chasing your tail on this one, I would defo contact the guy you got the ecu off of and seeif he has the matching sensor good luck with it as I know you will either be lucky or not.
 
Twincam1986 said:
I'm using FES. I don't remember it beginning with a P, but it may have done. I haven't got the full version so I have to write down whatever comes up - I only jotted it down quickly. But that's definitely what the rest of it said.
Click to expand...

Check FES log files. The error code will be stored in the log file. It will also contain more information relating to the actual fault that will help you diagnose the problem ..
 
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I can't see any option in FES to check log files? Is that full version only?

I've just re-scanned the car and it says what I've already posted along the top of the errors screen. Then at the bottom it says 'The reason for this error is plausability. No other information is available'.

I managed to find a crash sensor locally today so have just come to fit it. What the hell is it held on with? It seems to be some kind of round fixing with no flats on the edges and no key in the middle, so I don't see a way of actually removing it. After all this I am never buying a Fiat again, I've spent more time under the stupid thing than driving it.

Until I can work out how to remove the thing, would it do any harm to unplug it and connect the new one instead to see if the code will clear (bearning in mind it won't properly be in situ, if that makes a difference?)
 
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Update again, I couldn't really see why it would be a problem to unplug the old sensor and plug in the new one, so I just did this and.....fault is still present and will not clear.

I can only assume then that either this ecu has crash data stored on it which needs removing or there is a problem somewhere with the wiring to the crash sensor. I think I'll have to take it back to Fiat.
 
indeed airbags don't provide 'P' or 'U' Codes they are usually short numbers.

Any way crash sensor plausibility means the sensor believes that it is "plausible' it has been in an accident in the event of this happening, and combined with the right circumstances it will deploy the airbags however the reason you have the error code it that it is stuck in this state. it could be the sensor or the wiring could even be the replacement ecu not sure on the Stilo but there is generally an internal airbag crash sensor and at least one external which can be referenced against one another to establish if there has been an accident

you have a fault finding mission i'm afraid, start with a known good external sensor or try your Airbag ECU in a known good car.
 
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