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
Notice:
Dtcs for the can communication system are as
follows: u0073, u0100, u0105, u0121, u0122, u0123,
u0124, u0126, u0129, c1280, c1296, c1297, and
b1499.
Refer to the troubleshooting procedures of each
system if dtcs regarding the can communication
system are not output.
Turn th ...
Center power outlet socket (for ac power supply)
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 console rear end panel (see page ip-
19)
...
On-vehicle inspection
Check front seat side airbag assembly (vehicle not involved in
collision)
Perform a diagnostic system check (see page rs-
49).
With the front seat side airbag installed on the
vehicle, perform a visual check. If any of the defects
mentioned below are present, replace the fron ...