C5 2002 2.0 Hdi - Imobiliser Fault

[ando7p]

Hi folks - kind of embarrassed as it has been an awful long time since I dropped on here, let alone contributed. Nice to see some of the familiar names still around and ticking.

 

Anyway, the problem! Couple of weeks ago key in as normal, turn, engine spins and fires into life then immediately cut out. BONG - Engine Imobiliser Fault displayed. Super. Only time I've ever had this happen before was when I had disconnected the battery. Do the normal lock / unlock but to no avail.

 

Disconnected the battery for five minutes, reconnect, key in ignition, hold 'lock' down for 10 seconds, lock and unlock doors and hey presto! Life in the old dear.

 

Since then tickover seems around 150 rpm lower. It hasn't threatened to stall but it just seems lower. Weird and may be my imagination.

 

Tonight, shorts and training vest on ready to head off to the gym - BONG - Engine Imobiliser Fault. Do the usual lock / unlock to no avail. Battery off. Reconnect. Re-sync key (just in case), lock / unlock. No good. Tried several times. Left the battery off longer. No good. Trawled the tinterweb for any possible answers but the only thing different I could find was a reference to the airbag fuse. Look in the Haynes manual only not to find which one it was! Took them all out but didn't find any blown.

 

Reconnect battery, lock / unlock and hey presto, she fires up! OK, maybe a bit of a duff connection. Switch off. Lock car. Unlock. Key in - BONG!!! Losing the will to live and need the car next weekend to tow the old tin box 300 miles to Cornwall for 2 weeks r n r.

 

Does anyone have any ideas, pointers, reliable cars they can lend me? Or is there a way of bypassing the imobiliser?

 

Thanks in advance.

Edited June 11, 2013 by ando7p

[paul.h]

It could be a problem with the immobiliser transponder aerial which sits around the ignition barrel. You could try the spare key to help eliminate the immobiliser chip in the key.

 

I suspect the key remote initialisation procedure you are doing is only for the alarm/central locking receiver and not the immobiliser and if so, it may not be giving you the quick fix you think you are getting.

[coastline taxis]

Have you tried changing the battery in the key

[ando7p]

Thanks for the suggestions. With the main battery off all night and on trickle charge I had no problems today but now the confidence is rocking! Will try using the key only (spare is only a key and not fob / plip). Going to change the battery on the plip just to rule that out too. Is it possible to completely disable the immobiliser? Thinking it may be wise for a few weeks as I can ill afford to lose my holiday!

[coastline taxis]

itl cost you more to remove the imobiliser that it would to fix the fault. but till you get a diagnostic done your basicly wasting your time.

[ando7p]

Well what a disaster! Evening before going away it wouldn't start. Fetched rac out who plugged in the gizmo to reveal a tail light out and an unknown fault! Couldn't get it started. Rushed around and managed to get a different car fitted with a tow bar and off we popped on our hols.

 

Arrived on site to find our caravan covered in oil. On inspection found the steering rack had a leak. After checking the engine oil it needed 2.5 litres to top it up! Didn't use the car for a few weeks whilst on holiday for obvious reasons. Complained to the place we got the car from and they agreed to take the car back.

 

So after the boring story and after returning home called a local recommended auto electrician who turned up as promised. Plugged in the gizmo and told me the unknown fault is actually a fault being returned by the can bus. On inspection he located a pin in one of the connectors that had been arcing and was burnt out. A few minutes later and a new pin fitted and eh voila, all good again. The faulty pin was responsible for sending the signal to the fuel pump which explains the reason why it would fire first time then just spin after that.

 

Apparently the fuse box on the C5 (and pugs) is known to be prone to failure, usually due to water ingress. So peeps, if faced with an immobiliser fault check the connectors in the engine fuse box before losing too much hair!

[paul.h]

I am pleased the fault is sorted and would never have guessed the cause, so your post is important for all of us.

 

Probably just as well it happened before you set off with the caravan, although the replacement car sounds a disaster.