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 troubleshootingOperation flow
Hint:
Perform troubleshooting in accordance with the
procedures below. The following is an outline of basic
troubleshooting procedures. Confirm the troubleshooting
procedures for the circuit you are working on before
beginning troubleshooting.
Ask
the customer about the conditions and en ...
Hitch
Trailer hitch assemblies have different weight capacities. Toyota recommends
the use of toyota hitch/bracket for your vehicle. For details,
contact your toyota dealer.
If you wish to install a trailer hitch, contact your toyota dealer.
Use only a hitch that conforms to the gross trailer weig ...
Terminals of ecu
Check occupant classification ecu
Measure the voltage of the connector.
...