Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
System Description
2010 Lexus LS 460L AWDSECTION System Description
WARNING: This page is about a different car, the 2010 Lexus GS 450h. However, it is still accessible from the selected car via links, so may be relevant.
- ENGINE IMMOBILIZER SYSTEM DESCRIPTION
- The engine immobilizer system determines whether or not to disable starting of the hybrid control system based on a comparison of the key's ID codes and the vehicle's pre-registered code. The immobilizer system compares the vehicle certification ECU's pre-registered ID code with the key-embedded transponder chip's ID code. If the ID codes do not match, the immobilizer system activates and the hybrid control system cannot be started. The certification ECU manages communication with the hybrid control system, power source control ECU, steering lock ECU and ID code box. When the ID codes of the transponder chip and certification ECU match, the certification ECU authorizes the starting of the hybrid control system.
- FUNCTION OF MAIN COMPONENT
Component Outline Transponder key coil/amplifier (built into power switch) Receives key ID code, amplifies ID code and outputs it to certification ECU Indoor electrical key oscillator Transmits key detection signals within detection area in vehicle interior upon receiving transmission request signal from certification ECU.
Certification ECU request signal is activated when key is brought into vehicle interior and power switch is pushed.Door control receiver Receives ID code from key in actuation area and transmits it to certification ECU Security indicator Illuminates or starts flashing.
Illumination is controlled by main body ECU RH. - SYSTEM FUNCTION
- Using entry function
- When the driver (or passenger) is sitting in the vehicle while carrying the key, and the brake pedal is depressed while the power switch is pressed, the power source control ECU recognizes that the hybrid start operation has occurred and sends a certification request signal to the certification ECU. Upon receipt of the certification request signal, the certification ECU 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 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 power switch indicator illuminates in green. Then the certification ECU 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 (via the ID code box) the steering lock ECU confirms that the certification ECU is certified and drives the steering actuator's motor until the steering lock is unlocked. After unlocking the steering lock, an unlock completed signal is sent to the certification ECU. Upon receipt of this signal, the certification ECU sends an unset command signal to the ID code box. Once this signal is received, the ID code box confirms that the certification ECU is certified, sends an immobilizer unset command signal to the hybrid control system and sends a security indicator light off signal to the main body ECU RH.
- Not using the entry function (when battery is depleted)
- When the driver is sitting in the vehicle while carrying the key and the brake pedal is depressed, the power source ECU recognizes that the stop light switch is on and sends a key confirmation request signal to the certification ECU. Upon receipt of this signal, the certification ECU drives the motor of the power switch's built-in immobilizer amplifier. At this time the power switch sends an RF wave communication signal to the immobilizer. If the driver holds the key up to the power switch at this time, the power switch receives the immobilizer RF wave signal and responds by sending a radio wave signal. When the power switch receives the radio wave signal from the key, it duplicates the signal and sends an ID code to the certification ECU. 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 power switch indicator illuminates in green. Then the certification ECU 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 (via the ID code box) the steering lock ECU confirms that the certification ECU is certified and drives the steering actuator's motor until the steering lock is unlocked. After unlocking the steering lock, an unlock completed signal is sent to the certification ECU. Upon receipt of this signal, the certification ECU sends an unset command signal to the ID code box. Once this signal is received, the ID code box confirms that the certification ECU is certified, sends an immobilizer unset command signal to the hybrid control system and sends a security indicator light off signal to the main body ECU RH.
- Using entry function
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.