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 troubleshootingOnly rear door rh lock / unlock functions do not operate
Description
The main body ecu receives lock / unlock switch signals and activates the
door lock motor accordingly.
Wiring diagram
Inspection procedure
Inspect rear door with motor lock assembly rh
Apply the battery voltage to the door lock motor and
check the operation of th ...
Inspection
Inspect camshaft timing oil control valve
assembly
Measure the resistance of the oil control valve.
Standard resistance
If the result is not as specified, replace the oil control
valve assembly.
Check the operation.
Apply battery voltage across the terminals and
chec ...
Removal
Hint:
Use the same procedures for the rh side and lh side.
The procedures listed below are for the rh side.
Remove front seat headrest assembly
Remove front seat assembly
Operate the power seat switch knob and move the
seat to the foremost position.
Using a screwdriver, d ...