Sounds as if the BECM is confused. Have you tried just disconnecting the battery (paying heed to the procedure at the top of this forum) and leaving it disconnected for five minutes before reconnecting to try and clear the BECM's 'head'? If the faults still persist then I would suspect an earthing problem - check battery earths first (both ends, although unlikely if the starter spins and the motor fires up OK), then earths around the BECM, then earths for the dash - RAVE will give you the relevant information on earthing points.