The engine immobiliser system is designed to prevent the vehicle from being stolen. 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.

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.
Engine immobiliser system
How to proceed with troubleshootingHazard warning switch circuit
Description
When the hazard warning signal switch is turned on, the turn signal flasher
relay (marking: flsh) in the
main body ecu turns on to flash the hazard warning signal lights.
Wiring diagram
Inspection procedure
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Canceling and resuming
the speed control
Pressing the cancel switch
cancels the speed control.
The speed control is also canceled
when the brake pedal is depressed.
(When the vehicle has been
stopped by system control,
depressing the brake pedal does
not cancel the setting.)
Pressing the "+RES" switch
resumes the cruise control
a ...
Cold start
Description
The electronic throttle control system (etcs) controls the engine idling
speed. The etcs operates the
throttle actuator to open and close the throttle valve, and adjusts the intake
air amount to achieve the
target idling speed.
In addition, the ecm retards the ignition timi ...