System Description

The engine immobilizer system is designed to prevent the vehicle from being stolen. This system users steering lock ECU that stores the key codes of authorized smart keys. If an attempt is made to start the engine using an unauthorized key, the ECU sends a signal to the ECM to prohibit fuel delivery and ignition, effectively disabling the engine.

When the steering lock ECU detects that the key unlock warning switch is ON, the ECU provides current to the transponder key coil and produces a faint electric wave. A transponder chip in the key and receives the faint electric wave. Upon receiving the faint electric wave, the transponder chip outputs a key ID code signal. The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ECU.

The ECU matches the key's ID code with the vehicle's ID code, which was previously registered in the ECU and then communicates the results to the ECM using SFI communication.

After the identification results show that the key's ID code matches the vehicle's ID code and the ECU has confirmed their match: 1) the immobilizer system does not immobilizer the engine and the engine starts controls (fuel injection control and ignition control) enter standby mode; and 2) the ECU transmits a security indicator signal that communicates "indicator off" to the theft warning ECU (theft deterrent ECU). Then, the theft warning ECU turns off the security indicator lamp.