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Home >> Toyota >> 2012 >> Prius Four >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (Engine Immobilizer System (Plug-In) (Diagnostics - Introduction)) >> Engine Immobiliser System >> System Description >> System Description
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System Description

WARNING: This page is about a different variant/trim than selected.
  1. ENGINE IMMOBILISER SYSTEM DESCRIPTION 

    The immobiliser system is a theft deterrent system that determines whether to disable starting of the hybrid control system based on a comparison of the key ID code and vehicle pre-registered code. The immobiliser system compares the certification ECU (smart key ECU assembly) preregistered ID code with the ID of the key-embedded transponder chip. If the ID codes do not match, the immobiliser system is activated and the hybrid control system cannot be started.

  2. FUNCTION OF MAIN COMPONENTS 
    Component Outline
    Power switch Informs the driver of any power source or system abnormality through the illumination stage of the indicator light.
    Transponder key coil (built into the power switch) Receives the ID code and transmits it to the certification ECU (smart key ECU assembly) when the key battery is too weak to respond to the tuner based on signals from the room oscillators.
    Key Receives the signals from the oscillators and returns the ID code to the door control receiver.
    Certification ECU (smart key ECU assembly)
    • Certifies the ID code received from the door control receiver.
    • Transmits the engine immobiliser set/unset request signals.
    • Certifies immobiliser disengage signals, and transmits each disengage signal to the hybrid vehicle control system.*1
    ID code box (immobiliser code ECU)*2 Receives the immobiliser disengage signals from the certification ECU (smart key ECU assembly), certifies them, and transmits each disengage signal to the hybrid vehicle control system.
    Power management control ECU Receives the signal from the certification ECU (smart key ECU assembly), and performs hybrid vehicle control system.
    Transmission control ECU Assembly Registers the ID verification code.
    Outputs the P position signal or Not P position signal to the power management control ECU.
    Indoor electrical key oscillator
    • Front, Center, Rear
    		 Transmits key detection signals within the detection area in the cabin upon receiving a transmission request signal from the certification ECU (smart key ECU assembly).
    A certification ECU (smart key ECU assembly) request signal is activated when the key is brought into the cabin and the power switch is pushed or brake pedal is depressed.
    Door control receiver Receives an ID code from the key in the detection area and transmits it to the certification ECU (smart key ECU assembly).
    Combination meter assembly
    • Security indicator light
    		 Illuminates or flashes.
    Illumination is controlled by the certification ECU (smart key ECU assembly).
    • *1: except Canada
    • *2: for Canada
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