Hi Allan , I think the fault code which logged 'ecm no communications' explains all of your problems. On these cars (with ME7.5.10 system)the ECUs comms line is passed via the immobiliser rather than directly onto the comms bus. This means that unless the immobiliser correctly communicates with the ECU on start-up , you will get precisely what you describe happening - non-start and no comms. This can be caused by a bad supply or earth to the immobiliser or possibly a fault with the immobiliser. It can be caused if the system does not shut down fully. If there is any residual voltage which prevents the immobiliser AND ECU from shutting down , then it will not reset the start sequence. I have had heard of this being caused by water ingress into the wiring harness. I have also been told by someone that they had a similar fault caused by a faulty air-bag module 'hogging' the comms line and preventing ECU to immobilier comms but I have not seen this myself.