They're all mad.

TD6, key goes in, immobiliser tells column lock to release which feeds back if it has.
Immobiliser then releases the key lock.
Key turns to on.
Immobiliser then tells ecu it can inject fuel.
Turn key to start.
The starter on TD6 is off the key to lull you into a false sense of security when you are trying to figure out problems.

I had Immobiliser codes up the ying yang across the immobiliser, steering column, ecu and instruments.

Steering column was duff which stopped the key turning. When I put the key in I didn't get the motor whirring noise it makes. Replaced that.

Then I had an auxiliary power fault on immobiliser and column, bad connection on fuse, cleaned the fuse blades.

Last fault was key blocked which was the key completely disabled by a unit somewhere, had to fall back on the spare key. I can't even programme this key back in now but it may be because there were too many failed attempts at starting the car. Should only need a new chip in that though.

If you have a diagnostic tool you should be able to read live data off the steering column which tells you if a key is valid etc. I had no live data off the immobiliser itself. But if you put a key in and no motor whine, the column is your best bet.
 
Last fault was key blocked which was the key completely disabled by a unit somewhere, had to fall back on the spare key. I can't even programme this key back in now but it may be because there were too many failed attempts at starting the car. Should only need a new chip in that though.

If you have a diagnostic tool you should be able to read live data off the steering column which tells you if a key is valid etc. I had no live data off the immobiliser itself. But if you put a key in and no motor whine, the column is your best bet.
theres an option to 'reset' the key so you can reprogram it back to the car again
 
Not seen that on any of my diagnostic stuff. What are you using?
I'm using SDD (TOPIx)
its in the security section - recover programmed keys

i dont recall exactly what it says but when you run it, says something along the lines of returning keys to a state where they can be programmed to the car

If the Vehicle Fails to Recognize a Previously Working Key: Recovering keys can re-sync stored data and resolve recognition issues.
 
i got the full text related to 'recover programmed keys':
This application will recover a previously working key(s) to a state where it can be programmed back to that vehicle.

•This application can be used if previously the replace lost/faulty key application was ran and all working keys were not available at time of testing.
•Once this has been run, the add key application needs to be completed to program the key(s) back to the vehicle.
 
That only resyncs central locking side of the fob as well. The chip read by the immobiliser is a magnetic chip in the key, no battery power, it works or it doesn't. A diagnostics machine is needed to code it.
 
The garage has offered to bypass the immobiliser for 400 euros … not sure if that’s the best idea. Would prefer to sync the key properly
 
If you're happy ith spanners, a replacement ecu with immobiliser disabled is £180, unplug the steering lock with ignition on, join 2 wires on the immobiliser and remove a solenoid on the ignition barrel. All can be done in 30 minutes. This completely removes the immobiliser stuff meaning easier to steal but as a last ditch effort........

Quick question though, does your steering column release with a whirring noise when you put the key in the ignition and lock with the same noise when you remove it?
 
If you're happy ith spanners, a replacement ecu with immobiliser disabled is £180, unplug the steering lock with ignition on, join 2 wires on the immobiliser and remove a solenoid on the ignition barrel. All can be done in 30 minutes. This completely removes the immobiliser stuff meaning easier to steal but as a last ditch effort........

Quick question though, does your steering column release with a whirring noise when you put the key in the ignition and lock with the same noise when you remove it?
Interesting, but then I would need to reprogram the ECU to the car ? Would it not be easier to just reprogram the key? … also weirdly the steering wheel lock doesn’t seem to ever be on… can turn it whether car is on or off etc
 
Interesting, but then I would need to reprogram the ECU to the car ? Would it not be easier to just reprogram the key? … also weirdly the steering wheel lock doesn’t seem to ever be on… can turn it whether car is on or off etc
Should still make a motoring whirring noise even if the lock hasn't engaged.

If its not making the noise, chances are it's the steering column that has failed and it's that which is stopping the car starting. Sounds odd but it is part of the immobiliser system. Most of the time it fails, the lock fails in the off position.

There are people who say they started the car by wiring up the steering lock to the interior light, or pulling and refitting a fuse, but that only works if the key is still good and recognised by the immobiliser. Mine wasn't so can't confirm or deny this trick on my car.

Apparently the ECU is a plug and play affair, no marrying needed but again, I don't trust a lot of people unless they've proved themselves or my experience backs up their claims.

Have a look here first:
 

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