ECU/Immobilizer Dead

Looking for some help before I decide to send it to the big car park in the sky.

7th Gen Tourer, alternator blew (rectifier issue). Battery never ran flat but light came on before I got to mechanics.

Alternator fixed, car starts fine.

However the car seems to now have no memory.
- remote central locking doesn't work from key
- keys cannot be paired with car (using known steps)
- alarm goes off constantly once any of rear doors or boot is open
- car can be started and driven but red alarm light is flashing constantly

Auto electrician has looked and cannot diagnose anything obvious and suspects an ECU issue.

Anyone recall a problem like this before. Obviously with the cars age its not cost effective to replace the ECU or spend too much money diagnosing the problem.

disconnect the battery for 20 minutes then see what happens.

edgeoftime said:

disconnect the battery for 20 minutes then see what happens.

Click to expand...

That made it worse.
It went back to alarming going off on opening the front doors, and going off while driving.
About 20 mins of driving returned it to the state above again

You can get ecu off ebay from about 30 pounds
What engine is in your tourer

There was a thread Hear with very similar symptoms and it was the back up battery on the alarm system.
This is a separate battery in case the main car battery fails.