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 troubleshootingFront power seat lumbar switch
Inspection
Inspect front power seat lumbar switch lh
Measure the resistance between the terminals when
the switch is operated.
Standard resistance
If the result is not as specified, replace the switch. ...
Ecm communication stop mode (2005/11-2006/01)
Description
Wiring diagram
Inspection procedure
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 ...
Power steering ecu
Components
Removal
Disconnect cable from negative battery
terminal
Remove instrument panel sub-assembly
upper
Remove the instrument panel (see page ip-4).
Remove power steering ecu
Disconnect the 4 connectors.
Remove the 3 nuts and remove the power steering
e ...