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 troubleshootingSlip indicator light remains on
Description
The slip indicator blinks during vsc and/or trc operation.
When the system fails, the slip indicator comes on to warn the driver.
For 2wd: with auto lsd switch on, when the hydraulic brake booster is at a high
temperature, the slip
indicator illuminates.
Wiring diagram
In ...
Diagnosis system
Description
Air conditioning system data and the diagnostic
trouble codes (dtcs) can be read through the
data link connector 3 (dlc3) of the vehicle. When
the system seems to be malfunctioning, use the
intelligent tester to check for malfunctions and
perform troubleshooting.
...
Rear door courtesy switch
Components
Removal
Hint:
Use the same procedures for the rh and lh sides.
The procedures listed below are for the lh side.
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal t ...