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 troubleshootingShort in driver side squib 2nd step circuit
Description
The driver side squib 2nd step circuit consists of the center airbag sensor,
the spiral cable and the
steering pad.
The circuit instructs the srs to deploy when the deployment conditions are met.
These dtcs are recorded when a malfunction is detected in the driver side squi ...
System voltage
Description
The battery supplies electricity to the ecm even when the ignition switch is
in the off position. This
power allows the ecm to store data such as dtc history, freeze frame data and
fuel trim values. If the
battery voltage falls below a minimum level, the memory is cleared and ...
Towing related terms
Gcwr (gross combination weight rating)
The maximum allowable gross
combination weight. The gross
combination weight is the sum
of the total vehicle weight
(including the occupants, cargo
and any optional equipment
installed on the vehicle) and the
weight of the trailer being towed
(inc ...