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 troubleshootingProblem symptoms table
Hint:
Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms are
listed in order of probability in the "suspected area" column of
the table. Check each symptom by checking the suspected
areas in the order they are listed. Replace p ...
Cooling system
On-vehicle inspection
Check cooling system for leaks
Remove the radiator reservoir cap.
Caution:
To avoid the danger of being burned, do not
remove the radiator reservoir cap while the
engine and radiator are still hot. Thermal
expansion will cause hot engine coolant and
steam to b ...
Back door lock
Inspection
Inspect back door with motor lock assembly
Apply the battery voltage to the door lock motor and
check the operation of the door lock motor.
Ok
If the result is not as specified, replace the door lock
assembly. ...