Operation CHARM: Car repair manuals for everyone.
Home >> Lexus >> 2011 >> IS F V8-5.0L (2UR-GSE) >> Repair and Diagnosis >> Accessories and Optional Equipment >> Antitheft and Alarm Systems >> Description and Operation >> Engine Immobilizer System

Engine Immobilizer System





THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILIZER SYSTEM: SYSTEM DIAGRAM





Communication Table













SYSTEM DESCRIPTION

1. ENGINE IMMOBILIZER SYSTEM DESCRIPTION

(a) The immobilizer system is a theft deterrent system that determines whether to disable starting of the SFI system based on a comparison of the key ID codes and the vehicle pre-registered code. The immobilizer system compares the vehicle certification ECU pre-registered ID code with the ID of the key-embedded transponder chip. If the ID codes do not match, the immobilizer system is activated and the SFI system cannot be started. The certification ECU (smart key ECU assembly) manages communication with the ECM, power source control ECU, steering lock ECU and ID code box (immobilizer code ECU). When the ID codes of the transponder chip and certification ECU (smart key ECU assembly) match, the certification ECU (smart key ECU assembly) authorizes the SFI system to start.

2. FUNCTION OF MAIN COMPONENTS





3. SYSTEM FUNCTION

(a) Using the entry function

(1) When the driver (or passenger) is sitting in the vehicle while carrying the key, and the engine switch is pressed while the brake pedal is depressed, the power source control ECU recognizes that the engine start operation has occurred and sends a certification request signal to the certification ECU (smart key ECU assembly). Upon receipt of the certification request signal, the certification ECU (smart key ECU assembly) sends a request signal to the indoor electrical key oscillator. Upon receipt of the request signal, the indoor electrical key oscillator sends a request signal to detect if the key is inside the vehicle. When the key receives this request signal, it answers by sending an ID code containing a response code through the glass antenna to the door control receiver. Upon receipt of the ID code, the certification ECU (smart key ECU assembly) analyzes the code. If the interior certification passes, then the power source control ECU sends a certification pass response signal. When the power source control ECU receives this signal, the ACC relay is switched on and the IG1 and IG2 relays are switched on in sequence. At this time, the engine switch indicator light illuminates in green. Then the certification ECU (smart key ECU assembly) checks that the power source mode has been changed and sends a steering lock command signal to the power source control ECU. After receiving this signal, the power source control ECU supplies power to the steering lock actuator. Then the steering lock ECU confirms that the certification ECU (smart key ECU assembly) is certified (via the ID code box (immobilizer code ECU)) and drives the steering actuator motor until the steering is unlocked. After unlocking the steering, an unlock completed signal is sent to the certification ECU (smart key ECU assembly). Upon receipt of this signal, the certification ECU (smart key ECU assembly) sends an unset command signal to the ID code box (immobilizer code ECU). Once this signal is received, the ID code box (immobilizer code ECU) confirms that the certification ECU (smart key ECU assembly) is certified, sends an immobilizer unset command signal to the ECM, and sends a security indicator light off signal to the main body ECU RH (cowl side junction block RH).

(b) Not using the entry function (when the key battery is depleted)

(1) When the driver is sitting in the vehicle while carrying the key and depressing the brake pedal, the power source control ECU recognizes that the stop light switch is on and sends a key confirmation request signal to the certification ECU (smart key ECU assembly). Upon receipt of this signal, the certification ECU (smart key ECU assembly) drives the immobilizer amplifier built in the engine switch. At this time, the engine switch sends an RF wave communication signal to the immobilizer. If the driver holds the key up to the engine switch at this time, the engine switch receives the immobilizer RF wave signal and responds by sending a radio wave signal. When the engine switch receives the radio wave signal from the key, it duplicates the signal and sends an ID code to the certification ECU (smart key ECU assembly). Upon receipt of the ID code, the code is analyzed. If the certification passes, a key certification pass response signal is sent to the power source control ECU while simultaneously sending a sound buzzer request signal to the meter ECU. When the power source control ECU receives this signal, the ACC relay is switched on and the IG1 and IG2 relays are switched on in sequence. At this time, the engine switch indicator light illuminates in green. Then the certification ECU (smart key ECU assembly) checks that the power source mode has been changed and sends a steering lock command signal to the power source control ECU. After receiving this signal, the power source control ECU supplies power to the steering lock actuator. Then the steering lock ECU confirms that the certification ECU (smart key ECU assembly) is certified (via the ID code box (immobilizer code ECU)) and drives the steering actuator motor until the steering is unlocked. After unlocking the steering, an unlock completed signal is sent to the certification ECU (smart key ECU assembly). Upon receipt of this signal, the certification ECU (smart key ECU assembly) sends an unset command signal to the ID code box (immobilizer code ECU). Once this signal is received, the ID code box (immobilizer code ECU) confirms that the certification ECU (smart key ECU assembly) is certified, sends an immobilizer unset command signal to the ECM, and sends a security indicator light off signal to the main body ECU RH (cowl side junction block RH).
pro multis · About Operation CHARM