STOP AND START SYSTEM Backup Boost Converter Circuit

DESCRIPTION

A backup boost converter is built into the engine stop and start ECU. The backup boost converter helps maintain the power source voltage when the engine is restarted by stop and start control.

This prevents various functions such as the audio and visual system from malfunctioning if the power source voltage drops due to the battery voltage dropping when the engine is restarted by stop and start control.

If any DTCs are output, troubleshoot the DTCs first.

Tech Tips

A relay function and fuse function are provided in the backup boost converter.

If there is a malfunction in any of the electrical system circuits connected to the backup boost converter, the fuse and relay functions shut off the malfunctioning circuit to protect other circuits (remains shut off until next trip).

When the electrical system circuit is shut off, power to the circuit is cut off, causing any systems connected to the circuit to be disabled.

The fuse function is reset* when the engine switch is turned off. If the malfunction still exists in the electrical system circuit that has been shut off by the relay function, it will be shut off again by the relay and fuse functions the next time the engine switch is turned on (IG).

*: A semiconductor fuse self resets according to electric signal.


    The backup boost converter supplies power to:

  • Tire pressure warning system

  • Power steering system

  • Lighting system

  • Telematics system

  • Navigation system

  • Audio and visual system

  • Blind spot monitor system

  • Headup display system

  • Lexus safety system +

  • CAN communication system

  • Lexus parking assist-sensor system

  • Panoramic view monitor system

  • Vehicle stability control system

  • Meter / gauge system


    The eco run vehicle converter assembly (external backup boost converter) supplies power to:

  • Navigation system

  • Audio and visual system

WIRING DIAGRAM

Click here

CAUTION / NOTICE / HINT

Note


  • Before replacing the engine stop and start ECU, read the number of starter operations and total number of engine starts and write it into a new engine stop and start ECU.

    Click here

  • After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU.

    Click here

  • After replacing the engine stop and start ECU, airbag sensor assembly*1 or yaw rate and acceleration sensor*2, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.

    Click here


    • *1: for Optitron Meter Type

    • *2: for TFT Meter Type

  • Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE


  1. CHECK PROBLEM SYMPTOMS


    1. Determine the trouble area by referring to the table below.

      Effect on Vehicle Trouble Area/Cause Fail-safe DTC Output Stop and start cancel indicator light Symptom Proceed to

      When the engine is restarted by stop and start control:


        The following symptoms may occur

      • Audio and visual system is reset

      • The combination meter assembly fades out

      • The steering wheel feels heavy when the engine is restarted*

        *A DTC may be stored in the power steering system

      Backup boost converter internal malfunction


      • Internal power source malfunction

      • Internal power source overvoltage

      • CPU duty malfunction

      • Communication cycle error

      Stop and start control prohibited P323B Blinks Systems stop operating during engine restart as the backup boost converter output voltage cannot be boosted A
      Battery voltage drop

      Systems on the converter output side do not operate


        B41 terminal: All of the following will not operate

      • Tire pressure warning system

      • Panoramic view monitor system

      • Navigation system

      • Audio and visual system

      • Headup display system

      • Lighting system


        B42 terminal: All of the following will not operate

      • Navigation system

      • Audio and visual system

      • Telematics system


        B43 terminal: All of the following will not operate

      • Navigation system

      • Audio and visual system

      • Lighting system


        IG41 terminal: All of the following will not operate

      • Tire pressure warning system

      • Blind spot monitor system

      • Headup display system

      • Panoramic view monitor system

      • Lexus parking assist-sensor system

      • Lexus Safety System +

      Overcurrent applied to an output terminal (output terminal relay circuit is shutoff)

      Stop and start control is prohibited

      (Connected ECUs or sensors may detect power source malfunction DTCs)

      B22C0 Blinks Systems do not operate as power supply from the converter is cut off A

      Systems do not operate

      (Due to converter input side malfunction)


        IG1 terminal: All of the following will not operate

      • Power steering system

      • Vehicle stability control system

      • Tire pressure warning system

      • Blind spot monitor system

      • Headup display system

      • Panoramic view monitor system

      • Lexus parking assist-sensor system

      • Lexus Safety System +

      • CAN communication system


        IG2 terminal: All of the following will not operate

      • Meter / gauge system

      • Telematics system


        ACC terminal: All of the following will not operate

      • Audio and visual system

      • Navigation system

      • Telematics system

      • Panoramic view monitor system

      Converter input circuit malfunction


      • Open or short to GND in IG1 circuit

      • Open or short to GND in IG2 circuit

      • Open or short to GND in ACC circuit

      Stop and start control prohibited - Does not blink (Blinks when communication error DTCs are stored) Systems do not operate as power supply from the converter is cut off B

      Systems on the converter output side do not operate

      (varies depending on the malfunctioning relay circuit the converter detected)


        AC41 terminal:

      • The telematics system will not operate.

      • The navigation system will not operate.

      • The audio and visual system will not operate.

      • The panoramic view monitor system will not operate.


        AC42 terminal:

      • The telematics system will not operate.

      • The navigation system will not operate.


        IG11 terminal:

      • The power steering system will not operate


        IG12 terminal:

      • The meter / gauge system will not operate


        IG13 terminal:

      • The telematics system will not operate.


        IG31 terminal:

      • The vehicle stability control system will not operate


        B12 terminal:

      • The telematics system will not operate.


        IL41 terminal:

      • The navigation system will not operate.

      • The audio and visual system will not operate

      Malfunction in circuits the converter supplies power to

      (between the converter and ECUs or sensors)


      • Open or short in the combination meter assembly circuit

      Related systems do not operate as the relay circuit in the converter is turned off - Does not blink (Blinks when communication error DTCs are stored) Systems do not operate as power supply from the converter is cut off B

        All of the following systems do not operate:

      • Tire pressure warning system

      • Lighting system

      • Telematics system

      • Navigation system

      • Audio and visual system

      • Blind spot monitor system

      • Auto glare-resistant EC mirror

      • Panoramic view monitor system

      • Lexus parking assist-sensor system

      • CAN communication system

      • Lexus Safety System +

      • Vehicle stability control system

      • Power steering system

      • Meter / gauge system


      • Open in BBC NO. 1 fuse circuit

      • Open in BBC NO. 2 fuse circuit

      • Short in converter circuit

      • Backup boost converter malfunction

      Stop and start control prohibited P0617 Does not blink (Due to disabled meter/gauge system) All systems that the converter supplies power to do not operate (see circuit diagram) A
      P323B

      The audio does not operate

      (until the engine switch is turned off)

      Excessive audio volume

      Data List item "State of BBC" displays "BBC Overcurrent" while the circuit is protected

      The relay circuit in the converter is turned off to cut off power supply to the audio and visual system (Returns to normal when the engine switch is turned off) - Does not blink

      If overcurrent is detected in the audio and visual system, system operation is disabled while the engine switch is on (IG)

      (Returns to normal when the engine switch is turned off)

      C

      • The telematics system, navigation system, audio and visual system, panoramic view monitor system cannot be turned off (short between AC41 and +B)

      • The telematics system and navigation system cannot be turned off (short between AC42 and +B)

      • The meter / gauge system cannot be turned off (short between IG12 and +B)

      • Communication error DTCs may be stored due to short between IG31 and +B

      Tech Tips

      Varies depending on the number of times an open occurs in the +B circuit

      Converter circuit malfunction


      • Short between AC41 and +B

      • Short between AC42 and +B

      • Short between IG12 and +B

      • Short between IG31 and +B

      - - Does not blink The converter cannot shut off the power source when the engine switch is turned off B

      Engine switch does not turn on (ACC) (short between ACC and +B)

      Engine switch does not turn off (short between IG1 or IG2 and +B)

      Engine stop and start ECU power source circuit malfunction


      • Short between ACC and +B

      • Short between IG1 and +B

      • Short between IG2 and +B

      - - Does not blink
      • Engine switch does not turn on (ACC)

      • Engine switch does not turn off

      B
      Result
      Proceed to
      A
      B
      C

    A
    C
    B
  2. CHECK ENGINE STOP AND START ECU (POWER SOURCE CIRCUIT)


    1. B007WRNC26
      *a

      Front view of wire harness connector

      (to Engine Stop and Start ECU)

      Disconnect the engine stop and start ECU connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A65-1 (BIN2) - Body ground Always 9.5 to 14 V
      A65-3 (BIN1) - Body ground Always 9.5 to 14 V
    3. Turn the engine switch on (ACC).

    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      J46-19 (ACC) - Body ground Engine switch on (ACC) 9.5 to 14 V
    5. Turn the engine switch on (IG).

    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      J46-18 (IG2) - Body ground Engine switch on (IG) 9.5 to 14 V
      J46-21 (IG1) - Body ground Engine switch on (IG) 9.5 to 14 V
    7. Turn the headlight dimmer switch (light control switch) to the tail or head position.

    8. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      J46-20 (ILL) - Body ground Headlight dimmer switch (light control switch) in tail or head position 9.5 to 14 V
    9. Turn the engine switch off.

    10. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      J46-18 (IG2) - Body ground Engine switch off 0 to 1 V
      J46-19 (ACC) - Body ground Engine switch off 0 to 1 V
      J46-21 (IG1) - Body ground Engine switch off 0 to 1 V
      Result
      Proceed to
      OK
      NG

    NG
    OK
  3. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - EACH ECU OR SENSOR)


    1. Disconnect the connector from the corresponding system ECU/sensor.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tire Pressure Warning ECU and Receiver (for Tire Pressure Warning ECU and Receiver Integrated with Electrical Key Receiver)
      Tester Connection Condition Specified Condition
      J46-2 (B41) - R23-7 (+B) Always Below 1 Ω
      J46-3 (IG41) - R23-1 (IG) Always Below 1 Ω
      J46-2 (B41) - Body ground Always 10 kΩ or higher
      R23-7 (+B) - Body ground Always 10 kΩ or higher
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      R23-1 (IG) - Body ground Always 10 kΩ or higher
      Tire Pressure Warning ECU and Receiver (for Tire Pressure Warning ECU and Receiver (Stand Alone))
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - S54-1 (IG) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      S54-1 (IG) - Body ground Always 10 kΩ or higher
      Front door trim board sub-assembly LH (front door ambient illumination light LH) (w/ Door Ambient Illumination Light)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - N12-1 (+) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      N12-1 (+) - Body ground Always 10 kΩ or higher
      Front door trim board sub-assembly RH (front door ambient illumination light RH) (w/ Door Ambient Illumination Light)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - M12-1 (+) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      M12-1 (+) - Body ground Always 10 kΩ or higher
      Rear door trim board sub-assembly LH (rear door ambient illumination light LH) (w/ Door Ambient Illumination Light)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - Q6-1 (+) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      Q6-1 (+) - Body ground Always 10 kΩ or higher
      Rear door trim board sub-assembly RH (rear door ambient illumination light RH) (w/ Door Ambient Illumination Light)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - Q5-1 (+) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      Q5-1 (+) - Body ground Always 10 kΩ or higher
      No. 1 interior illumination light assembly LH (footwell light LH)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - J13-2 (B) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      J13-2 (B) - Body ground Always 10 kΩ or higher
      No. 1 interior illumination light assembly RH (footwell light RH)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - J37-2 (B) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      J37-2 (B) - Body ground Always 10 kΩ or higher
      No. 1 interior illumination light assembly (front console light)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - J18-2 (B) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      J18-2 (B) - Body ground Always 10 kΩ or higher
      Interior illumination light sub-assembly (instrument panel ambient illumination light) (w/ Instrument Panel Ambient Illumination Light)
      Tester Connection Condition Specified Condition
      J46-11 (B43) - K10-2 (RRIL) Always Below 1 Ω
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      K10-2 (RRIL) - Body ground Always 10 kΩ or higher
      Instrument Panel Junction Block Assembly (DOME NO. 2 relay)
      Tester Connection Condition Specified Condition
      J46-2 (B41) - 2C-7 Always Below 1 Ω
      J46-2 (B41) - Body ground Always 10 kΩ or higher
      2C-7 - Body ground Always 10 kΩ or higher
      Power Steering ECU Assembly
      Tester Connection Condition Specified Condition
      J46-6 (IG11) - J4-1 (IG) Always Below 1 Ω
      J46-6 (IG11) - Body ground Always 10 kΩ or higher
      J4-1 (IG) - Body ground Always 10 kΩ or higher
      Radio Receiver Assembly (w/ Audio and Visual System (for 8 Inch Display))
      Tester Connection Condition Specified Condition
      J46-12 (B42) - J52-4 (+B1) Always Below 1 Ω
      J46-15 (AC42) - J52-3 (ACC1) Always Below 1 Ω
      J46-12 (B42) - Body ground Always 10 kΩ or higher
      J52-4 (+B1) - Body ground Always 10 kΩ or higher
      J46-15 (AC42) - Body ground Always 10 kΩ or higher
      J52-3 (ACC1) - Body ground Always 10 kΩ or higher
      Radio Receiver Assembly (w/ Navigation System or Audio and Visual System (for 12.3 Inch Display))
      Tester Connection Condition Specified Condition
      J46-12 (B42) - J50-17 (+B1) Always Below 1 Ω
      J46-15 (AC42) - J50-16 (ACC1) Always Below 1 Ω
      J46-12 (B42) - Body ground Always 10 kΩ or higher
      J50-17 (+B1) - Body ground Always 10 kΩ or higher
      J46-15 (AC42) - Body ground Always 10 kΩ or higher
      J50-16 (ACC1) - Body ground Always 10 kΩ or higher
      Multi-display assembly (for 8 Inch Display)
      Tester Connection Condition Specified Condition
      J46-15 (AC42) - J56-24 (ACC) Always Below 1 Ω
      J46-11 (B43) - J56-12 (B) Always Below 1 Ω
      J46-15 (AC42) - Body ground Always 10 kΩ or higher
      J56-24 (ACC) - Body ground Always 10 kΩ or higher
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      J56-12 (B) - Body ground Always 10 kΩ or higher
      Accessary Meter Assembly (for 12.3 Inch Display)
      Tester Connection Condition Specified Condition
      J46-15 (AC42) - J137-24 (ACC) Always Below 1 Ω
      J46-11 (B43) - J137-12 (B) Always Below 1 Ω
      J46-15 (AC42) - Body ground Always 10 kΩ or higher
      J137-24 (ACC) - Body ground Always 10 kΩ or higher
      J46-11 (B43) - Body ground Always 10 kΩ or higher
      J137-12 (B) - Body ground Always 10 kΩ or higher
      DCM (Telematics Transceiver) (w/ Telematics System)
      Tester Connection Condition Specified Condition
      J46-16 (B12) - J62-1 (+B) Always Below 1 Ω
      J46-26 (IG13) - J62-7 (IG2) Always Below 1 Ω
      J46-24 (AC41) - J62-8 (ACC) Always Below 1 Ω
      J46-16 (B12) - Body ground Always 10 kΩ or higher
      J62-1 (+B) - Body ground Always 10 kΩ or higher
      J46-26 (IG13) - Body ground Always 10 kΩ or higher
      J62-7 (IG2) - Body ground Always 10 kΩ or higher
      J46-24 (AC41) - Body ground Always 10 kΩ or higher
      J62-8 (ACC) - Body ground Always 10 kΩ or higher
      LEXUS Display Audio Controller (Remote Operation Board) (w/ Audio and Visual System (for 8 Inch Display))
      Tester Connection Condition Specified Condition
      J46-25 (IL41) - J59-1 (ILL+) Always Below 1 Ω
      J46-24 (AC41) - J59-14 (ACC) Always Below 1 Ω
      J46-25 (IL41) - Body ground Always 10 kΩ or higher
      J59-1 (ILL+) - Body ground Always 10 kΩ or higher
      J46-24 (AC41) - Body ground Always 10 kΩ or higher
      J59-14 (ACC) - Body ground Always 10 kΩ or higher
      Remote Touch (Remote Operation Board) (w/ Navigation System or Audio and Visual System (for 12.3 Inch Display))
      Tester Connection Condition Specified Condition
      J46-2 (B41) - g1-1 (+B) Always Below 1 Ω
      J46-25 (IL41) - g1-9 (ILL+) Always Below 1 Ω
      J46-24 (AC41) - g1-2 (ACC) Always Below 1 Ω
      J46-2 (B41) - Body ground Always 10 kΩ or higher
      g1-1 (+B) - Body ground Always 10 kΩ or higher
      J46-25 (IL41) - Body ground Always 10 kΩ or higher
      g1-9 (ILL+) - Body ground Always 10 kΩ or higher
      J46-24 (AC41) - Body ground Always 10 kΩ or higher
      g1-2 (ACC) - Body ground Always 10 kΩ or higher
      Blind Spot Monitor Sensor LH (w/ Blind Spot Monitor System)
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - X2-5 (BLB) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      X2-5 (BLB) - Body ground Always 10 kΩ or higher
      Blind Spot Monitor Sensor RH (w/ Blind Spot Monitor System)
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - W2-5 (BRB) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      W2-5 (BRB) - Body ground Always 10 kΩ or higher
      Millimeter Wave Radar Sensor Assembly (w/ Lexus Safety System +)
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - A70-8 (IGB) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      A70-8 (IGB) - Body ground Always 10 kΩ or higher
      Driving Support ECU Assembly (w/ Lexus Safety System +)
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - A72-7 (B) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      A72-7 (B) - Body ground Always 10 kΩ or higher
      Network Gateway ECU
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - J75-11 (IG1) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      J75-11 (IG1) - Body ground Always 10 kΩ or higher
      Forward Recognition Camera (w/ Lexus Safety System +)
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - U14-7 (IGB) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      U14-7 (IGB) - Body ground Always 10 kΩ or higher
      Parking Assist ECU (w/ Panoramic View Monitor System)
      Tester Connection Condition Specified Condition
      J46-2 (B41) - J73-2 (+B) Always Below 1 Ω
      J46-3 (IG41) - J73-6 (IG) Always Below 1 Ω
      J46-24 (AC41) - J73-1 (ACC) Always Below 1 Ω
      J46-2 (B41) - Body ground Always 10 kΩ or higher
      J73-2 (+B) - Body ground Always 10 kΩ or higher
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      J73-6 (IG) - Body ground Always 10 kΩ or higher
      J46-24 (AC41) - Body ground Always 10 kΩ or higher
      J73-1 (ACC) - Body ground Always 10 kΩ or higher
      Clearance Warning ECU Assembly (w/ Lexus Parking Assist-sensor System)
      Tester Connection Condition Specified Condition
      J46-3 (IG41) - J38-1 (IG) Always Below 1 Ω
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      J38-1 (IG) - Body ground Always 10 kΩ or higher
      Meter Mirror Sub-assembly (w/ Headup Display System)
      Tester Connection Condition Specified Condition
      J46-2 (B41) - K1-1 (B) Always Below 1 Ω
      J46-3 (IG41) - K1-2 (IG) Always Below 1 Ω
      J46-2 (B41) - Body ground Always 10 kΩ or higher
      K1-1 (B) - Body ground Always 10 kΩ or higher
      J46-3 (IG41) - Body ground Always 10 kΩ or higher
      K1-2 (IG) - Body ground Always 10 kΩ or higher
      Combination Meter Assembly
      Tester Connection Condition Specified Condition
      J46-10 (IG12) - J10-21 (IG+) Always Below 1 Ω
      J46-10 (IG12) - Body ground Always 10 kΩ or higher
      J10-21 (IG+) - Body ground Always 10 kΩ or higher
      Skid Control ECU (Brake Actuator Assembly)
      Tester Connection Condition Specified Condition
      J46-1 (IG31) - A41-45 (IG1) Always Below 1 Ω
      J46-1 (IG31) - Body ground Always 10 kΩ or higher
      A41-45 (IG1) - Body ground Always 10 kΩ or higher
      Steering Sensor
      Tester Connection Condition Specified Condition
      J46-1 (IG31) - J32-4 (IG1) Always Below 1 Ω
      J46-1 (IG31) - Body ground Always 10 kΩ or higher
      J32-4 (IG1) - Body ground Always 10 kΩ or higher
      Yaw Rate and Acceleration Sensor (for TFT Meter Display)
      Tester Connection Condition Specified Condition
      J46-1 (IG31) - J19-4 (IG) Always Below 1 Ω
      J46-1 (IG31) - Body ground Always 10 kΩ or higher
      J19-4 (IG) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG
    OK
  4. CHECK ENGINE STOP AND START ECU (EACH ECU OR SENSOR POWER SOURCE CIRCUIT)


    1. Disconnect the connector from the corresponding system ECU/sensor.

    2. Measure the voltage according to the value(s) in the table below.

      Tech Tips

      Measure the voltage at the corresponding terminals.

      Standard Voltage
      Tester Connection Condition Specified Condition
      R23-7 (+B) - Body ground*1 Always 10.5 to 16 V
      N12-1 (+) - Body ground *3 Always 10.5 to 16 V
      M12-1 (+) - Body ground *3 Always 10.5 to 16 V
      Q6-1 (+) - Body ground *3 Always 10.5 to 16 V
      Q5-1 (+) - Body ground *3 Always 10.5 to 16 V
      J13-2 (B) - Body ground Always 10.5 to 16 V
      J37-2 (B) - Body ground Always 10.5 to 16 V
      J18-2 (B) - Body ground Always 10.5 to 16 V
      K10-2 (RRIL) - Body ground *4 Always 10.5 to 16 V
      J50-17 (+B1) - Body ground*5 Always 10.5 to 16 V
      J52-4 (+B1) - Body ground*6 Always 10.5 to 16 V
      J62-1 (+B) - Body ground*7 Always 10.5 to 16 V
      J56-12 (B) - Body ground Always 10.5 to 16 V
      g1-1 (+B) - Body ground*5 Always 10.5 to 16 V
      J73-2 (+B) - Body ground*8 Always 10.5 to 16 V
      K1-1 (B) - Body ground*9 Always 10.5 to 16 V
      2C-7 - Body ground Always 10.5 to 16 V
    3. Turn the engine switch on (ACC).

    4. Measure the voltage according to the value(s) in the table below.

      Tech Tips

      Measure the voltage at the corresponding terminals.

      Standard Voltage
      Tester Connection Condition Specified Condition
      J50-16 (ACC1) - Body ground*5 Engine switch on (ACC) 10.5 to 16 V
      J52-3 (ACC1) - Body ground*6 Engine switch on (ACC) Engine switch on (ACC)
      J56-24 (ACC) - Body ground Engine switch on (ACC) 10.5 to 16 V
      J62-8 (ACC) - Body ground*7 Engine switch on (ACC) 10.5 to 16 V
      g1-2 (ACC) - Body ground*5 Engine switch on (ACC) 10.5 to 16 V
      J59-14 (ACC) - Body ground*6 Engine switch on (ACC) 10.5 to 16 V
      J73-1 (ACC) - Body ground*8 Engine switch on (ACC) 10.5 to 16 V
    5. Turn the engine switch on (IG).

    6. Measure the voltage according to the value(s) in the table below.

      Tech Tips

      Measure the voltage at the corresponding terminals.

      Standard Voltage
      Tester Connection Condition Specified Condition
      R23-1 (IG) - Body ground*1 Engine switch on (IG) 10.5 to 16 V
      S54-1 (IG) - Body ground*2 Engine switch on (IG) 10.5 to 16 V
      J4-1 (IG) - Body ground Engine switch on (IG) 10.5 to 16 V
      J62-7 (IG2) - Body ground*7 Engine switch on (IG) 10.5 to 16 V
      X2-5 (BLB) - Body ground*3 Engine switch on (IG) 10.5 to 16 V
      W2-5 (BRB) - Body ground*3 Engine switch on (IG) 10.5 to 16 V
      A70-8 (IGB) - Body ground*10 Engine switch on (IG) 10.5 to 16 V
      A72-7 (B) - Body ground*10 Engine switch on (IG) 10.5 to 16 V
      J75-11 (IG1) - Body ground Engine switch on (IG) 10.5 to 16 V
      U14-7 (IGB) - Body ground*10 Engine switch on (IG) 10.5 to 16 V
      J73-6 (IG) - Body ground*8 Engine switch on (IG) 10.5 to 16 V
      J38-1 (IG) - Body ground*11 Engine switch on (IG) 10.5 to 16 V
      K1-2 (IG) - Body ground*9 Engine switch on (IG) 10.5 to 16 V
      J10-21 (IG+) - Body ground Engine switch on (IG) 10.5 to 16 V
      A41-45 (IG1) - Body ground Engine switch on (IG) 10.5 to 16 V
      J32-4 (IG1) - Body ground Engine switch on (IG) 10.5 to 16 V
      J19-4 (IG) - Body ground*12 Engine switch on (IG) 10.5 to 16 V
    7. Turn the headlight dimmer switch (light control switch) to the tail or head position.

    8. Measure the voltage according to the value(s) in the table below.

      Tech Tips

      Measure the voltage at the corresponding terminals.

      Standard Voltage
      Tester Connection Condition Specified Condition
      g1-9 (ILL+) - Body ground*5 Headlight dimmer switch (light control switch) in tail or head position 10.5 to 16 V
      J59-1 (ILL+) - Body ground*6 Headlight dimmer switch (light control switch) in tail or head position 10.5 to 16 V

      • *1: for Tire Pressure Warning ECU and Receiver Integrated with Electrical Key Receiver

      • *2: for Tire Pressure Warning ECU and Receiver (Stand Alone)

      • *3: w/ Blind Spot Monitor System

      • *4: w/ Instrument Panel Ambient Illumination Light

      • *5: w/ Navigation System or Audio and Visual System (for 12.3 Inch Display)

      • *6: w/ Audio and Visual System (for 8 Inch Display)

      • *7: w/ Telematics System

      • *8: w/ Panoramic View Monitor System

      • *9: w/ Headup Display System

      • *10: w/ Lexus Safety System +

      • *11: w/ Lexus Parking Assist-sensor System

      • *12: w/ TFT Meter Display

      Result
      Proceed to
      OK
      NG

    OK
    NG
  5. CHECK AUDIO AND VISUAL SYSTEM


    1. Turn the engine switch off and wait for 1 minute.

    2. Turn the engine switch on.

    3. Lower the audio volume.

    4. Check if the audio and visual system operates normally.

      OK
      Audio and visual system operates normally.
      Result
      Proceed to
      OK
      NG

    OK
    NG
  6. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - RADIO RECEIVER ASSEMBLY)


    1. Disconnect the J52*1 or J50*2 radio and display receiver assembly connector.

    2. Disconnect the J46 engine stop and start ECU connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      J46-12 (B42) - Body ground Always 10 kΩ or higher
      J52-4 (+B1) - Body ground*1 Always 10 kΩ or higher
      J50-17 (+B1) - Body ground*2 Always 10 kΩ or higher

      • *1: for Audio and Visual System (for 8 Inch Display)

      • *2: for Navigation System or Audio and Visual System (for 12.3 Inch Display)

      Result
      Result Proceed to
      OK (for Audio and Visual System (for 8 Inch Display)) A
      OK (for Navigation System or Audio and Visual System (for 12.3 Inch Display)) B
      NG C

    A
    B
    C