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 troubleshootingYaw rate and deceleration sensor
Components
Removal
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove front seat assembly lh
For manual seat: ...
Short to b+ in can bus line
Description
There may be a short circuit between the can bus line and +b when there is
resistance between
terminals 6 (canh) and 16 (bat) or terminals 14 (canl) and 16 (bat) of the dlc3.
Wiring diagram
Inspection procedure
Notice:
Turn the ignition switch off before measuring ...
Indicators
The indicators inform the driver
of the operating state of the
vehicle's various systems.
Turn signal indicator
Headlight indicator
Tail light indicator
Headlight high beam indicator
Automatic High Beam
indicator
Fog light indicator (if
equipped)
Smart key system indicator*
1
Cruise control ...