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 ...
Check and replace ecu
Notice:
The connector should not be disconnected from
the ecu. Perform the inspection from the
backside of the connector on the wire harness
side.
When no measuring condition is specified,
perform the inspection with the engine stopped
and the ignition switch on.
Check that the con ...
Terminals of ecm
Check ecm
Disconnect the a9 and b30 connectors.
Measure the voltage and resistance of the wire
harness side connectors.
If the result is not as specified, there may be a
malfunction on the wire harness side. ...