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 troubleshootingTerminals of ecu (2005/11-2006/01)
Notice:
Turn the ignition switch off before measuring the
resistances of the main wire and the branch wire.
After the ignition switch is turned off, check that the
key reminder warning system and light reminder
warning system are not in operation.
Before measuring the resistance, leave ...
Rear speed sensor (for 4wd)
Components
Removal
Hint:
Use the same procedures for the lh side and rh side.
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 termin ...
Terminals of ecu
Check combination meter assembly
Disconnect the e19 meter connector.
Measure the voltage and resistance of the wire
harness side connector.
If the result is not as specified, there may be a
malfunction on the wire harness side.
Check heater control panel (for automat ...