how do you disable the immobiliser on my vauxhall astra . ?

More details of the car would help, the astra has been around a long time.
What are the symptoms? Was it running OK before, has it been sitting a while, have you checked the timing belt, is the engine turning over on the starter at the usual speed?
Does the immo or engine management light flash when you turn on the ignition?
If not it's unlikely to be the immo at fault.
Even if it is flashing it's unlikely to be the immo as such, more likely to be a problem with the chip in the key.
Try the spare key.
If you dont have a spare open the key you have and make sure the chip is in place.

cal777
July 2009