A4 immobiliser problem

[Deanh]

Been having problems with my immobiliser,


battery died a few months ago and as it was dying the immobiliser would kick in after 2 seconds of starting which I put down to the weak battery,


put a new battery on but had the same problem since, meaning to start the car I have to disconnect the battery for 20 seconds and as soon as I switch it off I have to do the same thing again to restart it,


Its been to the garage twice and put on vag com and 50/504a and on vag com it says the key signal is too weak, the instrument panel is clear of faults, and on the 50/50 software says the ecu is in static mode and won't talk to the immobiliser!!!!


anyone any ideas?




i have tried a more powerful battery but that still has the problem so I know it's not a battery fault and my key has no battery in it

 

[aragorn]

I think the battery is a red herring.

The normal immo activation is to shut the engine down after a second or two, so what you describe there isnt anything battery related.

Have you tried another key?

Might need a new reader coil, or sometimes the wiring to the coil causes issues.

 

[hades-]

as above iv sorted quite a few B5's with immob problems
changed the wire from reader and all was good
easy ish job to do and parts not a lot of £££.

 

[jcb]

where is the reader and how do you remove/replace/repair the wiring?

 

[aragorn]

Its part of the ignition barrel.

Not sure if you can swap the reader on its own, or if you need to buy a whole new barrel though.

The wiring on earlier cars can prove problematic though!