Immobilizer System
Immobilizer SystemHow the Circuit Works
The immobilizer system is designed to prevent the vehicle from being started without the owner's ignition key. If an attempt is made to start the vehicle with any other key, the immobilizer system will not enable the fuel supply system.
The immobilizer system consists of the ignition key, immobilizer control unit-receiver, immobilizer system indicator, PGM-FI main relays, fuel pump, and the ECM/PCM.
Battery voltage is supplied at all times to the PGM-FI main relay 1 and through fuse 7 (in the under-dash fuse/relay box) to the immobilizer control unit-receiver and the gauge control module. With the ignition switch in ON (II) or START (III), the immobilizer control unit-receiver and the ECM/PCM receive battery voltage through fuse 19 (in the under-dash fuse/relay box).
If the proper ignition key is used, the immobilizer control unit-receiver sends a coded signal to the ECM/PCM and illuminates the immobilizer system indicator LED for 2 seconds. The coded signal informs the ECM/PCM that the proper ignition key is being used. The ECM/PCM grounds the PGM-FI main relay 2, energizing it to provide power to the fuel pump. Following the first 2 seconds after the ignition switch is turned to ON (II) with the proper ignition key, the immobilizer system indicator LED turns off, and the engine will run under normal operating conditions.
When the ignition switch is turned to LOCK (0), the immobilizer system indicator LED will blink for about 5 seconds to signal that the immobilizer control unit-receiver has reset correctly.