The problem is worse when the vehicle is cold but can happen at any time on start-up.
The immobiliser light appears to behave correctly but when the vehicle exhibits the problem the Odo and trip display dashes when the ignition is turned on (they display correctly before it is). The vehicle then will not crank. If the ignition is repetitively cycled the displays give the correct values and the engine can then be started.
The engine and ABS both have stored codes of "U0140 lost comms with BCM" when the fault is evident and comms with BCM is impossible. The BCM has occasionally stored a code for ignition switch and I replaced it as I had one in stock.
The engine also had a historical code for "U0121 Lost comms with ABS"
The BCM also had a code for "U0100 lost comms with PCM".
I've had the BCM out and checked for dry joints and water damage but it appears fine. I will be doing some testing of the CAN lines I think but my worry is that the BCM is faulty or not waking for some reason.
Just wondering if BCM failure is a common problem.