E38 750 engine and transmissiun failsafe

I had pixel issues on my instrument cluster, so pulled the batteries and fixed the cluster. Didn't ralise the mileage issue then and drove with spare cluster. Do now!
I also had no heater, blocked core. Pulled batteries, half the car, and removed and cleaned heater cores.
Removing the security bolt on steering column was a pig - might be relevent. Elapsed time without batteries was several weeks.
Started up without problems, but "Engine failsafe" and "Transnission failsafe" now. ASC light on, but it was before.
INPA can't find either engine module, or transmission module.
Help!
Did I disturb the steering angle sensor with my hammer and chisel? Have I disturbed the CAN bus? Is my ASC module really faulty (I assumed it was cluster VIN issue), but faulty ASC could be pulling the CAN bus down? So could steering angle sensor?
Anybody got any bright ideas on what could be going on, and ideas on testing? I have got PA soft, but not installed yet. Might it help? I could then get it loaded.
Any suggestions welcome.
Mike