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 troubleshootingBattery temperature sensor circuit
Description
The battery temperature sensor installed on the battery current sensor
detects battery temperature.
A thermistor is integrated into the battery temperature sensor, and the
resistance in the battery
temperature sensor changes according to the battery temperature.
The r ...
Room temperature sensor (for automatic ai conditioning system)
Components
Removal
Remove lower instrument panel
Remove the lower instrument panel (see page ip-
16).
Remove room temperature sensor
Disconnect the duct.
Disconnect the connector.
Detach the claws and remove the sensor.
Inspection
Inspect room temperature ...
Master cylinder pressure sensor malfunction
Description
The master cylinder pressure sensor is connected to the skid control ecu in
the abs and traction
actuator.
Dtc c1281/81 can be detected when the master cylinder pressure sensor sends a
master cylinder
pressure signal or test mode ends. Dtc c1281/81 is output only in test mo ...