Audi A3 2013 UK RHD Car. Airbag Fault

   #1  

Dr Sheldon

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Sorry I didn't save a scan from this, can get one if really needed.

I have No Comms with 15 Airbag Module. All other Modules (Engine, ABS, Airbag, Instruments etc) are also throwing codes for No Comms with Airbag.

All other controllers are on Line and no other Fault codes anywhere

I have Load tested pins:

31 & 61 for Positive both Black Wires
63 for Earth which did have some resistance however I have rectified that now


62 Violet White is Linbus - tested with a scope

Pins 89 & 90 I have text book Can Signals viewed with a Pico Scope.

I have de pinned the Can wires from the plug - I still have Good CAN on those wires, however nothing when I scope the actual Pins from the Module with it correctly powered up and plugged in - I'm guessing I should see some wake up activity however small on Power Up. Both remain at 0v. I would expect 2.5v even with no CAN activity.

All testing done with the module in situ bolted in.
.

I'm now convinced I have a bad Bad Module and happy to fit a new one.


Just a couple of questions for you guys.

1. Have I done enough testing, or have I missed something on my wiring diagram and testing ?
2. Am I right in thinking the Lin bus wire plays no part in the communication between VCDS and the Airbag module ?


Many thanks
 
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Uwe

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1. Hard to say without seeing the applicable wiring diagrams.
2. Correct.

-Uwe-
 
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Uwe

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How can I attach PDF Document of Wiring Diagram from ERWIN ?
You cannot attach documents here, and this is a great example why. Wiring diagrams from erWin are copyrighted material and we don't wish to be responsible for the inherent copyright violation if they were hosted on a server that we control.

-Uwe-
 
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Dr Sheldon

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You cannot attach documents here, and this is a great example why. Wiring diagrams from erWin are copyrighted material and we don't wish to be responsible for the inherent copyright violation if they were hosted on a server that we control.

-Uwe-
Good Point.

Wise too !
 
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Dr Sheldon

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I'm now convinced that I have a bad module, Power Grounds & Data are all present and correct.

I have ordered a Genuine New Unit from Audi.


Bearing in mind I cannot read any coding etc from the old module, is the procedure for fitting the replacement straight forward or ?

Component Protection etc?


Should I be booking a Slot with my ODIS man?
 
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Uwe

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2013... Is that an 8P still, or an 8V already? An 8P should not have CP but an 8V will.

-Uwe-
 
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DV52

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^^^Uwe- The doctor's description of the pin assignments line-up very well with the WD for an 8V - so.............!!

Don
PS: but an interesting problem nevertheless -given the power-train CAN bus appears to be OK generally on the other modules except for J324!!
 
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   #9  

Dr Sheldon

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^^^Uwe- The doctor's description of the pin assignments line-up very well with the WD for an 8V - so.............!!

Don
PS: but an interesting problem nevertheless -given the power-train CAN bus appears to be OK generally on the other modules except for J324!!
Indeed an 8V.


DV52

This unit has failed but is not affecting the Power train CAN.

When Probed with the twisted wires on 89 & 90 de pinned I see 0v on the scope. Of course 0v (on a scope) can be just open Circuit or Ground. IF these wires were Short to Ground then, as we all know, the car would be in all kinds of trouble.

Unplugging the module would bring it back to life.


This a low mileage well maintained vehicle with the correct service history, belongs to a Pilot.


The Only reported symptoms are :

1. Airbag Light is on
2. Cruise no longer functioning
3. Stop Start not working.

I have a hunch that when 1. is fixed 2 & 3 will come back to life. If not we can produce &nwrite down a methodical, logical test plan to tackle them to.


Sincere thanks for the help guys :)
 
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