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 troubleshootingDifferent diameter tire malfunction
Description
The skid control ecu measures the speed of each wheel by receiving signals
from the speed sensor.
These signals are used for recognizing that all 4 wheels are operating properly.
Therefore, all wheel
signals must be equal.
Inspection procedure
Check tire size
...
Ig power source circuit
Description
This is the main power source supplied to the air conditioning amplifier when
the ignition switch is on
(ig). This power source is used for operating components, such as the air
conditioning amplifier and
servo motors.
Wiring diagram
Inspection procedure
Inspect fuse (ec ...
Precaution
Handling precaution
When handling the electronic parts:
Avoid any impact to electronic parts such as
ecus and relays. Replace with new ones if
dropped or subjected to a severe blow.
Do not expose any electronic parts to high
temperatures and humidity.
Do not touch the connec ...