Engine Immobiliser System (W/O Entry And Start System) System Description

Vehicle Interior. Land Cruiser. Urj200, 202 Grj200 Vdj200
Theft Deterrent Keyless Entry. Land Cruiser. Urj200, 202 Grj200 Vdj200

  1. IMMOBILISER SYSTEM DESCRIPTION

  1. FUNCTION OF MAIN COMPONENTS

  1. SYSTEM FUNCTION

Engine Immobiliser System (W/O Entry And Start System) -- System Description



IMMOBILISER SYSTEM DESCRIPTION
The immobiliser system is designed to prevent the vehicle from being stolen. This system uses the transponder key ECU assembly that stores the key ID codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the transponder key ECU assembly sends a signal to the ECM to prohibit fuel delivery and ignition, effectively disabling the engine.

FUNCTION OF MAIN COMPONENTS

Component
Outline
Transponder key ECU assembly
  1. When a key is inserted into the ignition key cylinder, the transponder key ECU assembly checks if the key ID code received from the transponder key coil and registered key ID code match.
  2. When the engine is started, the transponder key ECU assembly checks if the engine ID codes stored in the ECM and transponder key ECU assembly match.
Transponder key coil
When a key is inserted into the ignition key cylinder, the transponder key amplifier receives the key ID code from the transponder chip in the key grip and outputs it to the transponder key ECU assembly.
ECM
The ECM receives key ID code verification results from the transponder key ECU assembly. The ECM also verifies the ECUs. Then judgment of whether to immobilize the engine is made.
Unlock warning switch assembly
The unlock warning switch assembly detects if the key is in the ignition key cylinder and outputs the result to the transponder key ECU assembly.
Front door courtesy light switch assembly LH*
The front door courtesy light switch assembly is located on the driver door.
This detects door status (open or closed) and outputs data to the transponder key ECU assembly. This turns on when the driver door is open and turns off when the door is closed.
  1. *: for LHD

SYSTEM FUNCTION

  1. When the transponder key ECU assembly detects that the unlock warning switch assembly is on, the transponder key ECU assembly applies current to the transponder key coil and produces a magnetic field around the antenna coil. A transponder chip in the key grip outputs a key ID code signal using electromotive force generated by the magnetic field. The transponder key coil receives the signal and sends it to the transponder key ECU assembly. The transponder key ECU assembly checks if the key ID code received from the transponder key coil matches the registered key ID code.
    When the engine is started, the ECM communicates with the transponder key ECU assembly and checks the key verification result. In addition, the ECM checks if the engine ID codes stored in the transponder key ECU assembly and ECM match. If they do not match, the ECM prohibits engine start.