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 troubleshootingGcwr, twr and unbraked twr
Confirm that the gross trailer weight, gross combination weight, gross
vehicle weight, gross axle weight and tongue weight are all within the
limits.
Gcwr*
2Wd models: 5985 lb. (2715 Kg)
Awd models: 6100 lb. (2765 Kg)
Twr*
1500 Lb. (680 Kg)
Unbraked twr*
1000 Lb. (450 Kg)
*: ...
Diagnosis system
Check dlc3
The ecm uses iso 15765-4 for communication. The
terminal arrangement of the dlc3 complies with sae
j1962 and matches the iso 15765-4 format.
If the result is not as specified, the dlc3 may have a
malfunction. Repair or replace the harness and
connector.
Hint:
Conn ...
Control module communication bus off
Description
The power steering ecu receives signals from the ecm and the skid control ecu
via the can
communication system.
Hint:
When 2 or more dtcs starting with [u] are output simultaneously, inspect
the connectors and wire
harness of each ecu.
If dtc u0105/41 is output, fi ...