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 troubleshootingBrake switch "B" circuit high
Description
The purpose of this circuit is to prevent the engine from stalling while
driving in the lock-up condition when
the brakes are suddenly applied.
When the brake pedal is depressed, this switch sends a signal to the ecm. Then
the ecm cancels the
operation of the lock-up clutch ...
Data list / active test
Read data list
Hint:
Using the intelligent tester's data list allows switch,
sensor, actuator and other item values to be read without
removing any parts. Reading the data list early in
troubleshooting is one way to save time.
Connect the intelligent tester (with can vim) to the
dlc3 ...
Gcwr, 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)
*: ...