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 troubleshootingVehicle speed signal error (test mode dtc)
Description
The tire pressure warning ecu receives a speed signal from the combination
meter. This dtc is stored
upon entering test mode, and cleared when a vehicle speed signal of 12 mph (20
km/h) is detected for 3
seconds or more. The dtc is output only in test mode.
Wiring diagram ...
Front axle hub bolt
Components
Replacement
Hint
Use the same procedures for the rh side and lh side.
The procedures listed below are the lh side.
Remove front wheel
Remove front disc brake cylinder
assembly lh (see page br-40)
Remove front disc (see page br-42)
Remove front axle hub bolt
...
Problem symptoms table (2006/01- )
Hint:
Use the table below to help determine the cause of the
problem symptom. The potential causes of the symptoms are
listed in order of probability in the "suspected area" column
of the table. Check each symptom by checking the suspected
areas in the order they are listed. Replace p ...