killerwatts

I disconnected my instrument cluster yesterday to try to figure out the fading led problem that happens when my car has been running and for giggles tried to start my car with cluster out (it wouldn't). I then reinstalled my cluster and tried to start car and (it wouldn't)tried with all keys. I ran diagnostic and as I expected it said immobilizer issue, key issue, and control module disabled. I cleared fault codes but same codes reappear. Should I clear codes and disconnect and reconnect cluster to re sync keys to immobilizer or will I need to tow to dealer and have them recode keys. I am under the impression that the keys are linked to the ECM and immobilizer and by me installing cluster before clearing faults I basically installed cluster in faulted mode and until I clear and connect cluster on cleared faults the keys will not work until then. Does this make sense?

PaulW

Disconnect and reconnect the plugs to the instrument cluster....that's the problem, you have a bad connection.

killerwatts

I cleared DTC's and disconnected and reconnected the instrument cluster. No change. I still get the same DTC's after they were cleared. I also just disconnected and reconnected the green connector on back of cluster after clearing DTC's no change. I cleared DTC's and removed negative terminal from battery for about 10-15 seconds (no change)

WillemS

I'm having this same fault code problem now, but my Immobilizer is not triggered, nor am I prevented from starting/running the car.. I replaced the worn out LCD in the Cluster of my 2001 Allroad A6 C5. Replacement LCD was OEM, and works fine, but getting a fault code that "18058 - Powertrain Data Bus: Missing Message from Instrument Cluster P1650 " As for as an incomplete cluster cable connection, the plugs have those special locking devices, that click each, as the 3 plugs are inserted.
Any additional thoughts appreciated.