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 troubleshootingHow to proceed with troubleshooting
Hint:
Use these procedures to troubleshoot the tire pressure
warning system.
*: Use the intelligent tester.
Vehicle brought to workshop
Inspect battery voltage
Standard voltage:
11 to 14 v
If the voltage is below 11 v, recharge or replace the battery
before proceeding.
...
Diagnosis system
Description
When troubleshooting obd ii (on-board diagnostics)
vehicles, the intelligent tester (complying with sae
j1987) must be connected to the dlc3 (data link
connector 3) of the vehicle. Various data in the vehicle's
ecm (engine control module) can be then read.
Obd ii regulations ...
System description
Lighting system
Illumination control system (illuminated entry
system):
When the doors are unlocked by a key or
transmitter operation, or when a door is opened or
closed, the illuminated entry system turns on the
room light, map light, foot light and ignition key
cylinder light*1 o ...