Smurfman

So we have an A4, we have had to replace the Central Locking system due to water damage in the rear quarter panel.
But since we replaced it, and a dead battery later, the car thinks the Clutch is not being pressed when attempting to start it.

We pulled the clutch switch and tested with continuity depressing and releasing, it seems to be working just fine.

Not sure what to look at next to see why the car thinks the clutch is not pressed.
Open to ideas.

Thanks
J

EuroPartShop!

Check the wiring harness connected to the clutch switch for any signs of damage or corrosion. Sometimes, even a small break in the wiring can cause issues with the signal being properly transmitted. Ensure that all relevant fuses related to the clutch interlock system are intact and not blown. A blown fuse could disrupt the circuit and cause the car to not recognize when the clutch is pressed.

The issue could also potentially lie with the ECU, especially if there were any electrical disturbances during the central locking system replacement or the dead battery incident. It might be worth checking for any error codes stored in the ECU's memory that could point to the source of the problem.

Smurfman

Well, a little update here... on the PNP relay, we determined that the ground (red/white wire pin 6/B should be ground while cranking) and should come from the Central Locking Control Module - we determined that that wire from that module must have a break in it or something.

So we spliced in a ground from that wire to the relay, effectively giving it ground all the time.

Hit the key, and the car started right up.