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 troubleshootingAir fuel ratio sensor
Components
On-vehicle inspection
Check air fuel ratio compensation system
Connect the intelligent tester to the dlc3.
Turn the ignition switch on.
Select the following menu items: data list / a/fs b1
s1 and o2s b1 s2.
Warm up the a/f sensor with the engine speed at
2,500 ...
Before refueling the vehicle
Close all the doors and windows, and turn the engine switch to the
“lock� position (vehicles without a smart key system) or off (vehicles
with a smart key system).
Confirm the type of fuel.
Fuel types
Unleaded gasoline (octane rating 87 [research octane number 91] or
higher)
Cauti ...
Headlight switch
The headlights can be operated
manually or automatically.
Turning on the headlights
Operating the switch
turns on the lights as follows:
U.S.A. (Type A)
The side marker, parking,
tail, license plate, instrument
panel lights, and
daytime running lights turn on.
The headlights and all
light ...