Antitheft and Alarm Systems: Description and Operation

IMMOBILIZER SYSTEM

System Description
The vehicle is equipped with an immobilizer system that will disable the vehicle unless the proper ignition key is used. This system consists of a transponder located in the ignition key, an immobilizer receiver unit, an indicator light, and the PCM.




When the key is inserted in the ignition switch and turned to the (II) position, the immobilizer receiver unit sends power to the transponder in the ignition key. The transponder then sends a coded signal back through the immobilizer receiver unit to the PCM.




- If the proper key has been used, the immobilizer indicator light will come on for about two seconds, then go off.
- If the wrong key has been used whose code was not received or recognized by the unit, the indicator light will come on for about 2 seconds, then it will blink until the ignition switch is turned OFF.
- If the ignition switch is turned OFF, the indicator will blink for about 5 seconds to signal that the unit has been set correctly, then the indicator will go off.
- If the customer has lost his key, and cannot start the engine, contact Acura Customer Relations.

How the Circuit Works
The immobilizer system is designed to prevent the car from being started without the owner's ignition key. If 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, PGM-FI main relay, fuel pump, and the PCM.

With the ignition switch in ON (II) or START (III), the immobilizer receiver unit and the PCM receive an "ignition on" signal through fuse 46 and the PGM-FI main relay. The PCM then sends power to the ignition key transponder through the immobilizer receiver unit. The transponder then sends a coded signal back to the PCM through the receiver. If the signal is correct, the PCM will energize 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 will not energize 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.