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 troubleshootingIgnition coil
Description
Hint:
These dtcs indicate malfunctions relating to the primary circuit.
If dtc p0351 is set, check no. 1 Ignition coil with igniter circuit.
If dtc p0352 is set, check no. 2 Ignition coil with igniter circuit.
If dtc p0353 is set, check no. 3 Ignition coil with igniter cir ...
Removal
Notice:
Do not heat the vehicle body, emblem and name plate
excessively.
Hint:
When removing the emblem and name plate, heat the vehicle
body, emblem and name plate using a heat light.
Standard heating temperature
Remove no. 1 Back door emblem assembly
Put protective tape aroun ...
Communication
Description
The skid control ecu sends signals such as cruise control cancel demand
signals and brake operation
demand from ecm response signals to the ecm when the cruise control system is in
operation.
Inspection procedure
Hint:
This circuit uses can communication. Therefore, if t ...