Technical Urgent help needed with posibel front airbag sensor fault!

[frciy86]

Hi!

I am in need of some help with identifying if truly my front airbag crash sensor (the one under the bonnet) is faulty or not.I have checked it via FES and it returns something like C03 front impact sensor fault intermediant or something like that.Now as far as i can tell the car never had any front crash damage, but I suspect that maybe the wiring is causing the problem.
Does anyone know where the wires from the front impact sensor feed in the D4 connector or how can I check if the sensor id good or not?!.I most know this because if indeed the sensor is faulty then I need to buy one or I will be spending a lot less by running 2 new wires to the sensor if that id working fine.
If anyone know this please help me...:worship:

 

[Deckchair5]

The front crash sensor K39 wiring goes through front dashboard connector D1 (not D4) and then on to the airbag unit M60

You could check for normally open circuit either at the crash sensor or at connector A pins 2 and 4 of the airbag ECU M60

 

[frciy86]

Thank you for the quick reply Deckchair5!!!:worship:
I checked the sensor and it was an open circuit...does that mean that the sensor is good or not?Oh yes the D1 connector is that the brown connector under the fuse box in the battery tray (can you attach me a picture?)?!
I will check the open circuit at the D1-K39-and airbag unit(witch one is connector A...the first or the second one?).

 

[Deckchair5]

Open circuit= normal =good
Closed circuit= crash detected


M60 connector A is the not so wide 24 pin connector
(M60 connector B is the wider 32 pin connector)

If you check the circuit at the M60 connector A then you won't need to check D1

 

[frciy86]

thank u again for the reply Deckchair5!

Today I have checked the sensor and the wiring at connectors.
So at the sensor it showed me that it is an open connection (no current can flow true) and the same at connector A pin 2 and 4 at the airbag ecu.I replaced the sensor with a wire and it showed me a closed circuit (current flows) at connector A pins 2 and 4 so that means that the wiring is ok to.
The whole story is that i've replaced my airbag ecu with a second hand one, but with crash data stored on the ecu (the car witch from the ecu came from had a front crash with both front airbags deployed), and a "specialist" deleted the crash data(from the airbag ecu reading out the eeprom and rewriting it) but it seems that somehow the error stored by the front crash sensor stayed in the memory of the ecu.
Is that posible?
Or is there a posibility that still may from crash sensor has an internal problem of some kind??

thanks fro the reply on this in advance...:worship:

 

[Deckchair5]

You were saving the important information until last eh?

As you know, once the airbag ecu has detected a crash then the data has to be deleted and it sounds as if your specialist didn't do that properly or there is an internal short circuit in the airbag ECU so you would need to take it back to them. But an airbag ECU from a crashed car is more than suspect and if the specialist isn't checking it out properly then what if it triggers the airbags whilst you're driving?

At least it sounds like your front crash sensor wiring is behaving normally

 

[frciy86]

Yes...probably I should started with that info(ecu rewrite etc.)...sorry..
So this Friday I will take the ecu to the "specialist" so he can rewrite it for me.
Till then I made a print screen from FES with the stored error :bang:.
I hope that this provides more info about the current situation.
Thanks again Deckchair5 :worship:

 

[cab01942]

View attachment 87368
The front crash sensor K39 wiring goes through front dashboard connector D1 (not D4) and then on to the airbag unit M60
View attachment 87374
You could check for normally open circuit either at the crash sensor or at connector A pins 2 and 4 of the airbag ECU M60

Please be careful when proffering tech info as inaccuracy can mislead people. The circuit is not normally open, it has very high resistance! If you disconnect the wiring to the sensor you have a truly open circuit; and the associated warning light and fault code. The circuit allows a very small current to flow which is sensed (via a 220,000 ohm resistor) by the airbag system. This is by-passed by the internal switch when a collision occurs allowing the full current to flow and trigger the airbags.