System Description

The engine immobilizer system is designed to help prevent the vehicle theft. This system uses a transponder key ECU that stores the key codes of authorized ignition 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 ECU detects that the 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 grip receives the electric wave. Upon receiving the 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 compares key's ID code with the previously registered vehicle ID code. If the key ID code and vehicle ID code match, the ECU turns off the security indicator lamp and communicates the results to the ECM through SFI communication. The ECM then sets the engine starting systems (fuel injection control and ignition control) to standby mode.