Immobiliser Fault

**hebridean** · 24-02-2010,10:24 PM

My Wifes 2001 A6 Avant 1.9tdi will start for a couple of seconds and then cuts out. As i'm at work offshore at the moment i asked a mechanic friend to do a diagnostic test on it and it showed a immobiliser fault. He told my wife that he will have to phone a mate of his to find out what to do about it. So i thought i would do a bit of surfing to see if it could be reset or switched off, but this does not appear to be possibe and i thought i would ask if any of you good people on this forum have any suggestions on how to fix the fault.

Many thanks.

**Shaka1976** · 24-02-2010,11:00 PM

Ok I had a similar fault and here is what the AA man did.

1:Lock car on key fob
2:Unlock car on key fob
3:Open door(get in) close door
4:Turn ignition on and leave on for 15 mins
5:Turn ignition off
6:Get out of car a lock with keyfob
7:Unlock car with KEY and get in
8:Start car within 30 seconds

This apparently resets the immobilizer to the key. I had been having problems for weeks, since doing this I have had no problems for 6 months.

**shark_90** · 24-02-2010,11:05 PM

I've never heard of that resetting the immobiliser. Sounds like an over-complicated procedure that's meant to sound impressive to me.

The immobiliser can be removed from the ECU, some specialists around the country could do that for you. We could do it for you by post if you wanted to take the ECU out and send it to us.

It's likely to be the ignition barrel reader coil or perhaps the instrument cluster at fault.

**Padwick** · 24-02-2010,11:05 PM

Nice one Shaka.

Printed for future reference.

**lonky** · 24-02-2010,11:05 PM

does sound like key getting out of sync with car. Normally happens with spare key, or when fob battery low.

I have done the same to reset mine before, except not to wait 15 mins.

**shark_90** · 24-02-2010,11:28 PM

Originally Posted by lonky

does sound like key getting out of sync with car. Normally happens with spare key, or when fob battery low.

The fob battery is only for the remote, not for the immobiliser transponder. The transponder is powered by the magnetic field emitted by the reader coil.

**hebridean** · 25-02-2010,07:56 AM

Many thanks to you all for your helpfull replies which i will e-mail to my wife.

Thanks again.

**philfingers** · 25-02-2010,01:54 PM

you can also get an immobilser fault show up if the main battery is weak and you try to start the car, I think the voltage drops low enough to mean the immobilser cuts in. May not be an issue but then again the fault could have been stored a long time back. Worth resetting all fault codes first

**hebridean** · 25-02-2010,07:50 PM

I have just phoned my wife after advising her of Shaka's suggestion via an e-mail this morning and "hey presto" the car is now alive again and my wife is happy. Fantastic.

**Shaka1976** · 25-02-2010,08:35 PM

Originally Posted by hebridean

I have just phoned my wife after advising her of Shaka's suggestion via an e-mail this morning and "hey presto" the car is now alive again and my wife is happy. Fantastic.

Glad to be of service, I always like to try the 'NO COST' options before taking any car to a specialist.