Immobilizer Control System Introduction

The immobilizer control system is an anti-theft device that immobilizes the vehicle. It stops the engine from working and prevents the vehicle from being stolen. It mainly consists of the following components.

• Engine Control Module (ECM)
• Immobilizer control module (ICM) with the built-in coil antenna
• Ignition key with the built-in transponder

A code called the transponder code is memorized in the transponder. And, the code is registered with ECM. Basically, when the ignition switch is turned ON, ECM reads the code by the coil antenna. Then, if the code in transponder in the ignition key does not match with the one registered with ECM, ECM stops the operation of the fuel injection so as not to start up the engine and turns the immobilizer indicator lamp ON and OFF using CAN communication lines. (In addition to the above operation, ECM also turns the immobilizer indicator lamp ON and OFF when some trouble is detected in the keyless start system.)