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 troubleshootingTerminals of ecu
Check instrument panel junction block (main body ecu)
Disconnect the ib and ie junction block connectors.
Measure the voltage and resistance of the wire
harness side connectors.
Reconnect the ib and ie junction block connector.
Measure the voltage of the wire harness ...
Stop light switch circuit
Description
While driving with the cruise control, if the ecm detects that the brake
pedal is depressed, the cruise
control operation will be canceled. The stop light switch sends brake pedal
status signals to the ecm.
When the brake pedal is not depressed, terminal st1- is equal to the ...
Occupant classification system malfunction
Description
The occupant classification system circuit consists of the center airbag
sensor and the occupant
classification system.
When the center airbag sensor receives signals from the occupant classification
ecu, it determines
whether or not the front passenger airbag, front seat side ...