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immobiliser query


26 Aug 2004
Can anybody tell me if the immobiliser on my '94 LHD 993 C2 is built into the ECU or if it is a separate unit?

It is playing up on me and I have been advised to either repair or replace the unit.

According to Bosch, only Porsche can play around with these units because no-one else has access to the diagrams.......

Thanks, Mart

Migration info. Legacy thread was 17893
Hello Mart, I have had the same problem on an LHD 993 Carrera 2. Porsche Centres and Porsche GB will not help to deal with the Bosch immobiliser, which in my case shut down altogether immobilising the engine. Posrche GB says UK spec cars do not have this immobiliser system when delivered and therefore they cannot help at all.

The problem was initiated by using a spare Porsche-delivered key which started the car but then refused to work five minutes later after the engine had been switched off. There was no Porsche cure, but a Bosch service centre (Aberdeen) eventually by-passed the immobiliser unit which is located under the passenger seat (LHD remember) and the car runs again. However, the immobiliser circuit is still looking for the Bosch unit and therefore the fast blinking door lights do not switch into slow blink mode after locking. Result, flat battery after 12 hours.

I seek to reactivate the Bosch system again when I can find somebody to do the job, which does not include any Porsche Centre I have tried or Porsche GB. The solution I fear is to be found in Germany where this system is fitted as standard from new.

Porsche GB technical helpline people say they have had this problem before with LHD cars but have no advice to offer, despite dialogue with the factory.

Migration info. Legacy thread was 18303
although on my leftie I had the immobliser high flash on & off randomly a few times recently..... :?

er.... aint those bosch service centres for white goods ?

Migration info. Legacy thread was 18306
Mark and Richard,

Sorry to hear your stories, dosen't sound good does it?! It's making me nervous now. I have an aftermarket alarm fitted already to my car, but not sure what happened to the Drive Block. If Porsche GB is not able to help then I guess there's no point me taking it to OPC. The people who installed the alram must have bypassed the Drive Block somehow. How do you activate/deactivate the Drive Block? Do you have a remote key fob? If so, what does it look like? Would it mean a new ECU? (££££)

Migration info. Legacy thread was 18314

Can you describe the symptoms please?

Migration info. Legacy thread was 18320
Oh no, I don't have any problem with it at the moment, but I've only got one key fob and I'm planning on getting a new Thatcham one. Just need to know what is going on inside my car at the moment.

Migration info. Legacy thread was 18327

Are immobiliser issues definitely still an OPC-only issue? My car has decided not to listen to either of it's alarm fobs at the moment so, although I can get into the car using the key, I can't do anything else! Chelsea Carrera normally look after my car but they're not answering the phone so I guess they're off till the new year.

Anyone know anything I can try?


Migration info. Legacy thread was 103928

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