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 troubleshootingUnlock warning switch
Inspection
Inspect unlock warning switch assembly
Measure the resistance of the switch.
Standard resistance
If the result is not as specified, replace the switch
assembly.
Ecu power source circuit
Description
This circuit provides power to operate the transponder key ecu.
Wir ...
Reassembly
Hint:
Use high-temperature grease to lubricate the bearings,
gears, return spring and steel ball when assembling the
starter.
Install planetary gear
Apply grease to the planetary gears and pin parts of
the planetary shaft.
Install the 3 planetary gears.
Install starter arm ...
Stop light switch circuit
Description
While driving with the cruise control, if the ecm detects that the brake
pedal is depressed, the cruise
control operation will be canceled. The stop light switch sends brake pedal
status signals to the ecm.
When the brake pedal is not depressed, terminal st1- is equal to the ...