UK Car Repair Questions? Ask a Mechanic for Answers ASAP
for the immobilser light to remain on then its not disabling as it should
1st thing to try is some fresh batteries in the key fob and also try a 'hard' reset where
by disconnecting the battery cables and clamping them together for 10 mins. Remove both battery leads from the battery then use a nut and bolt or G-clamp to hold both battery lead terminals together.
This dischargesany capacitors / memory within the ECU and around the car so ensures all memory settings are wiped clear - back to the factory default.
This will reset all the systems on the car and you may need the radio security code to get it going again, and ensure that the keys are in your hand when you re-connect the battery as the car may lock and turn on the alarm