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 troubleshootingThrottle / pedal position sensor
Hint:
These dtcs relate to the accelerator pedal position (app) sensor.
Description
Hint:
This etcs (electronic throttle control system) does not use a throttle cable.
The app sensor is mounted on the accelerator pedal bracket and has 2 sensor
circuits: vpa (main) and
vpa2 (sub). This ...
Operation check
Illuminated entry system operation check
The illuminated entry system controls the following
lights:
Ignition key cylinder light*1 or transponder key
amplifier*2
Foot light
Map light and room light
Hint:
*1: W/o engine immobiliser system
*2: W/ engine immobiliser ...
Compressor and pulley (for 2gr-fe)
Components
Removal
Discharge refrigerant from
refrigeration system (see page ac-172)
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensione ...