OK, weird one.

L319 (Range Rover Sport) TDV6 auto in for BCM change.
Old BCM is displaying a problem with the rear electric windows not working, and flagging an internal error.
Customer wants it fixed, as working windows is part of safety inspection here.

Bought a used BCM (Exactly the same version and part number), and installed it - flashed correct SW and synched config file no problem.
Rear windows now work, but no crank!
No fault codes at all - and no immobiliser messages.

This has got me a bit stumped, as I didn't think that the starter motor trigger went through the BCM (according to RAVE diagram, it doesn't on the TDV6 auto!)
I turn the key, I hear a relay click down there - which I think is for load relief - but no bloody crank!!!

Nothing else untoward...
Any ideas?

Thanks,

Mike.







This has got me a bit

 

Did you swap the original BCM back in?

 

Try a soft reset then hard rest.

 

Yes, tried original BCM back in - and it starts.
Tried soft and hard reset - no go.

Does the start relay earth go through the BCM on an auto?

 

BCM is the main component for Immobilizer. It stores the key data. I don't know what tool you used to programmed the spare module, but it should have prompted you to learn the keys.

Workshop info says you cannot swap used BCMs, but I would learn the keys and see what it does.