ENGINE IMMOBILISER SYSTEM (w/o Smart Key System) SYSTEM DESCRIPTION


  1. ENGINE IMMOBILISER SYSTEM DESCRIPTION

    The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses the transponder key ECU assembly that stores the key 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.

  2. FUNCTION OF MAIN COMPONENTS

    Component Outline
    Transponder key ECU assembly Checks the key ID code received from the transponder key amplifier and if the results match, an engine start permission signal is sent to the ECM.
    Transponder key amplifier When a key is inserted into the ignition key cylinder, the transponder key amplifier receives the key ID code. Then the transponder key amplifier amplifies the key ID code and outputs it to the transponder key ECU assembly.
    ECM The ECM receives key ID verification results from the transponder key ECU assembly. The ECM also verifies the ECUs. Then judgment of whether to immobilise 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.
    Security indicator light (air conditioning control assembly) Depending on the operation of the transponder key ECU assembly, the security indicator light comes on or starts blinking.

  3. SYSTEM FUNCTION


    1. When the transponder key ECU assembly detects that the unlock warning switch assembly is on, the transponder key ECU assembly provides current to the transponder key coil built-in transponder key amplifier and produces radio waves. A transponder chip in the key grip receives the radio waves. Upon receiving the radio waves, the transponder chip outputs a key ID code signal. The transponder key coil receives this signal, which is amplified by the transponder key amplifier, and the signal is transmitted to the transponder key ECU assembly.

      The transponder key ECU assembly matches the key ID code with the vehicle ID code, which was previously registered in the transponder key ECU assembly, and communicates the results to the ECM.

      After the identification results show that the key ID code matches the vehicle's ID code and the transponder key ECU assembly has confirmed their match: 1) the engine immobiliser system does not immobilise the engine and the engine starting controls (fuel injection control and ignition control) enter standby mode; and 2) the transponder key ECU assembly transmits a security indicator light signal that communicates "security indicator light off" to the air conditioning control assembly. Then, the air conditioning control assembly turns off the security indicator light.

    2. The security indicator light blinking pattern is as shown below (when changing from the immobiliser set status to the unset status):

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