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 troubleshootingSystem description
General
The front passenger occupant classification system
judges whether the front passenger seat is occupied
or not in accordance with the seat belt buckle
status; and whether the seat is occupied by an adult
or child (with child seat) in accordance with the load
that is applied ...
Automatic
air conditioning system
Air outlets and fan speed are automatically adjusted according
to the temperature setting.
Driver’s side temperature control
dial
Automatic mode button
Micro dust and pollen filter
mode button
Driver’s side temperature setting
display
Fan speed display
Air outlet display ...
Checking monitor status
Perform monitor drive pattern
Connect the intelligent tester to the dlc3.
Turn the ignition switch and the tester on.
Clear the dtcs (see page es-35).
Run the vehicle in accordance with the applicable
drive pattern described in readiness monitor
drive pattern (see page es-19). Do ...