On a Scion tC, when the immobilization is triggered what is disabled ? engine cranking? engine ignition? or fuel injectors?

 

Immobilizer works with ECU. If key doesn't match immobilizer, ECU won't trigger fuel or spark. Basically same as having bad ECU or no ECU. Cranking engine will still work because that's separate independent circuit.

 

add fuel pump as I have discovered, thank you very much for your reply