Airbag light after seat removal

[Papagut]

Good morning,

I have a dashboard airbag warning light on in my 04 Cayenne Turbo, and have been to a local shop to have it reset. Apparently the fault is persistent - as soon as it is cleared it reappears. I suspected perhaps the seatbelt, which seems a fairly common source of this warning, but the fault reads: Control module faulty - upper limit value exceeded, test conditions are not completed, fault is currently active and causing a DTC light. I now suspect the problem began when I was working on an unrelated electrical problem. At that time the battery was disconnected, multiple harnesses and fuses were removed, and at least at one point, one seat was fully removed - definitely while the key was in the ignition, possibly even while the car was running. I understand that this may have caused the fault, but need help resolving it.

Any help would be greatly appreciated,

Mark

[Loren]

You will need to try and reset it with a Porsche PIWIS tester and if it does not reset then get the fault code number as it will point to the problem.

[Papagut]

The shop attempted the reset when they did the scan for me. They used a Durametric setup to do the scan, so my first question would be is that different than the PIWIS tester, or will the PIWIS tester have a different result when attempting to reset the fault?

Furthermore, there is no specific code on the printout the shop gave me, it gives me a part number, a controller ID, then under Current Fault Codes it says 3: then gives the description I provided above.

The only possible clue to the specific fault code that I can see is at the bottom of the page, where there is a web address of the report - at the end it says:...\955-Airbag_FaultCode.html. Perhaps 955 is the error code?

Let me know if that helps.

Mark

[Loren]

Fault code 0003 Control module faulty

Possible cause of fault

- Airbag triggering unit faulty

If you have tried to reset and it will not reset them I'm afraid you need a new airbag control unit. Sorry.

[Papagut]

I thought that may be the case, but wanted to make sure it was not all my dis-connecting and re-connecting that had caused the issue. I can also remember disconnecting the unit itself at some point. I will go back and check it to see if I bent any pins or if the plugs are not seated properly. If I recall, it is under the center console - just behind the shifter.

If that changes anything, let me know. Otherwise I will post back any developments.

Thanks,Mark

[Loren]

Remember that when the key is in the ignition the airbag circuit is live. So always remove the key and better yet disconnect the battery before removing the seat connectors.

[Papagut]

I wish I would have know that, rookie mistake I suppose. In your opinion, given the scan details, do you feel that removing the seat and turning on the ignition would have caused a hard code to be registered in the control unit - something that could be cleared by a reset - or that the control unit itself is permanently damaged or defective? The difference is significant: $100 versus $1300.

Regards,

Mark

[Loren]

Well, if you can not reset it with a PIWIS tester then you will need to replace it. These are sensitive trigger units and I don't think they like voltage spikes - as I have see this sort of problem before on both the sports cars and Cayennes.

[Papagut]

Thanks, for the assistance.

Let me make sure I understand you clearly: the technician that performed the scan attempted to clear the code, after which he said that it just came back up instantly - but you are indicating to reset the ecu. Are those the same things, or should I be asking them specifically to "reset the control unit", then to "clear the code" via the PIWIS tester?

Just making sure I am clear.

Thanks,

Mark

[Loren]

DME is not part of the error - the error is only reported through the DME.

The error is generated in the airbag control box (not the DME) and that is what needs to be reset. I only suggest attempting a reset with PIWIS as last ditch effort before buying a new control unit.

[Papagut]

Thanks - crystal clear.

Mark

[Papagut]

In the end, I was able to get the ECU reset at a fraction of the cost of purchasing one new. Anyone need contact information to the shop that did it for me - let me know.