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 troubleshootingTerminals of ecu
Check combination meter assembly
Measure the voltage and resistance of the
connector.
Check instrument panel junction block (main body ecu)
Measure the voltage and resistance of the
connectors.
...
Ambient temperature sensor circuit
Description
The ambient temperature sensor is installed in the front part of the
condenser to detect the ambient
temperature and control the air conditioner. The sensor is connected to the
combination meter and
detects fluctuations in the ambient temperature. This data is used for
contr ...
Throttle actuator control motor current range / performance
Description
The etcs (electronic throttle control system) has a dedicated power supply
circuit. The voltage (+bm)
is monitored and when it is low (less than 4 v), the ecm determines that there
is a malfunction in the
etcs and cuts off the current to the throttle actuator.
When the volt ...