2000 A4 1.8 Immobiliser Issue

[rickyboy]

Hi, I'm wondering if anyone has any ideas on how to fix an intermittent immobiliser fault. This is different from the reader fault I believe, as the symptoms are completely different to my other A4 which did have the reader coil problem.

The car will have problems starting from cold. It will start no problem if the car has been running and you stop it and restart it again. The immobiliser light will extinguish as it should after turning the ignition on but the car will start, then stop. I've had it on vagcom and the engine module has logged an immobiliser fault, however the instruments/immobiliser modules have no fault codes.

I've tried all the tricks - Shorting battery cables, resetting the engine module with vagcom etc to no avail

I believe the problem could be electrical and be releated to the relays. I can manage to get the car to start by messing about with relay 382 which doesn't make a great deal of sense because the car will start sometimes even if this relay is removed. I have heard something about the xcon relay causing problems with starting but have no idea which relay number it is. The manual has no mention of relay numbers only fuses (same with Haynes manual).

Any pointers are greatly appreciated.

Thanks,

Richard.

[rya4]

my imobiliser does not like the remote but with the key works everytime have you tried that?

[rickyboy]

Thanks for the quick reply. I have two remote fobs and both have the same symptoms. Just tried the emergency key and it has started the engine but rather interestingly the immobiliser light is flashing now. It will take a few days to check if this solves the problem as the fault is intermittent and it started fine with the fob key as well which I tried first.

[rya4]

mine only like's to start if you unlock the door with the key no pressing of buttons just old fashion key turning.

[rya4]

and it like's to be locked with key aswell otherwise it might not start either