Circuit Description
Immobilizer SystemHow the Circuit Works
The immobilizer system is designed to prevent the car from being started without the owner's ignition key. It an attempt is made to start the car with any other key, the immobilizer system will disable the car's fuel supply.
The immobilizer system consists of the ignition key, immobilizer receiver unit, immobilizer indicator light, PGM-FI main relay, fuel pump, and the PCM or ECM.
With the ignition switch in ON (II) or START (III), the immobilizer receiver unit and the PCM or ECM receive an ignition on" signal through fuse 46 and the PGM-FI main relay. The PCM or ECM then sends power to the ignition key transponder through the immobilizer receiver unit. The transponder then sends a coded signal back to the PCM or ECM through the receiver. If the signal is correct, the PCM or ECM will enable the car's fuel supply system by grounding the PGM-FI main relay. The immobilizer indicator light flashes a code to indicate that the correct key has been inserted. If the ignition key signal is not correct, the PCM or ECM will not enable the car's fuel supply system by not grounding the PGM-FI main relay. The immobilizer indicator light then flashes a code to indicate that an incorrect key has been inserted.