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 troubleshootingMaintenance requirements
To ensure safe and economical driving, day-to-day care and regular
maintenance are essential. It is the owner’s responsibility to
perform regular checks. Toyota recommends the following maintenance:
General maintenance
General maintenance should be performed on a daily basis. This can
be done ...
Curtain shield airbag assembly
Components
On-vehicle inspection
Check curtain shield airbag assembly (vehicle not involved in
collision)
Perform a diagnostic system check (see page rs-
49).
With the curtain shield airbag assembly installed on
the vehicle, perform a visual check. If any of the
defects ...
Driving position memory
Your preferred driving position (the position of the driver’s seat) can
be recorded and recalled by pressing a button.
Two different driving positions can be recorded into memory.
Recording procedure
Check that the shift lever is in p.
Turn the engine switch to the “on” position (ve ...