This car came to me as a non runner, not even cranking, lots of faults as soon as the ignition was turned on, and immobilizer light did not go off.
A bit of investigation and common sense, revealed that the engine ECU was not being powered, creating all the symptoms ...
Further investigation revealed that a damaged wire.
Vibrations made the wire insulation to worn out, and as soon as the coper strands got exposed the moisture did the rest.
After the wire repaired, the immobilizer light went off, no more faults coming up, and the engine started.
Hope this can help you!