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 passenger airbag assembly
Components
On-vehicle inspection
Check front passenger airbag assembly (vehicle not involved in
collision and airbag not deployed)
Perform a diagnostic system check (see page rs-
49).
With the front passenger airbag installed on the
vehicle, perform a visual check:
chec ...
Engine compartment
Engine coolant reservoir
Engine oil filler cap
Battery
Brake fluid reservoir
Fuse box
Radiator
Condenser
Electric cooling fans
Engine oil level dipstick
Washer fluid tank
Engine oil
With the engine at operating temperature and turned off, check the oil
level on the dips ...
Back door
The back door can be locked/unlocked and opened/closed by
the following procedures.
Locking and unlocking the back door
Door lock switch
Entry function (if equipped)
Wireless remote control
Opening/closing the back door from inside the vehicle (vehicles
with a power back door)
Press a ...