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 troubleshootingSliding roof control switch circuit
Description
If either the sliding function or tilt function does not operate, there may
be a malfunction in the sliding roof
control switch circuit.
Wiring diagram
Inspection procedure
Perform active test by intelligent tester (sliding roof operation)
Select the active test, use ...
Ig power supply voltage malfunction
Description
The power steering ecu distinguishes the ignition switch status as on or off
through the ig power
source circuit.
Wiring diagram
Inspection procedure
Read value of intelligent tester (ig power supply)
Connect the intelligent tester (with can vim) to the
dlc3.
...
Inspection
Inspect starter assembly
Notice:
These tests must be performed within 3 to 5 seconds
to avoid burning out the coil.
Perform the pull-in test.
Disconnect the lead wire from terminal c.
Connect the battery to the magnetic switch as
shown in the illustration. Check that the clutch ...