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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Electrical >> Starter >> Stop And Start System - Circuit Tests & Symptom Tests (2 Of 3) >> Stop And Start System >> Backup Boost Converter Circuit [10/2022 - 11/2023] >> Procedure

Backup Boost Converter Circuit [10/2022 - 11/2023]: 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 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
      • Duty error
      • Communication cycle error
      		 Stop and start control prohibited P323A-00
      P323B-29
      P323B-38      		 Does not come on Converter output voltage cannot be boosted when the engine is restarted A
      Battery voltage drop
      Systems on the converter output side do not operate

      B41 terminal: All of the following will not operate

      • Headup display system
      • Tire pressure warning system
      • Fog light assembly

      B42 terminal: The air conditioning system will not operate

      B43 terminal: Both of the following will not operate

      • Lighting system
      • Digital rear-view mirror system

      IG41 terminal: All of the following will not operate

      • Blind spot monitor system
      • Digital rear-view mirror system
      • Parking support brake system
      • Air conditioning system
      • Headup display system
      • Dynamic radar cruise control system
      • CAN communication system

      EMOP terminal: The oil pump with solenoid assembly will not operate      		 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)      		 X087A - Systems do not operate as power supply from the converter is cut off E
      Systems do not operate
      (Due to converter input side malfunction)

      IGP terminal: Both of the following will not operate

      • Safety connect system
      • Meter / gauge system

      IGR terminal: All of the following will not operate

      • Blind spot monitor system
      • Tire pressure warning system
      • Digital rear-view mirror system
      • Air conditioning system
      • Parking support brake system
      • Headup display system
      • Dynamic radar cruise control system
      • Electronically controlled brake system
      • Power steering system

      ACC terminal: -
      ILL terminal: Air conditioning system will not operate      		 Converter input circuit malfunction
      • Open or short to GND in IGR circuit
      • Open or short to GND in IGP 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)
      IG12 terminal: The meter / gauge system will not operate

      IG31 terminal: Both of the following will not operate

      • Electronically controlled brake system
      • Power steering system

      IG41 terminal: Both of the following will not operate

      • Tire pressure warning system
      • Parking support brake system

      B12 terminal: The Safety connect system will not operate

      B41 terminal: All of the following will not operate

      • Headup display system
      • Tire pressure warning system
      • Fog light assembly

      B42 terminal: The Meter / gauge system will not operate
      B43 terminal: The Lighting system will not operate
      IL41 terminal: The Air conditioning system will not operate      		 Malfunction in circuits the converter supplies power to
      (between the converter and ECUs or sensors)      		 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
      • Digital rear-view mirror system
      • Meter / gauge system
      • Electronically controlled brake system
      • Power steering system
      • Audio and visual system
      • Blind spot monitor system
      • Air conditioning system
      • Parking support brake system
      • Headup display system
      • Dynamic radar cruise control system
      • Fog light assembly
      • Air conditioning system
      • CAN communication system
      • Dynamic radar cruise control system
      • Safety connect system
      • Audio and visual system
      • Open in BBC fuse circuit
      • Short in converter circuit
      • Backup boost converter malfunction
      		 Stop and start control prohibited P0615-11 Does not blink (Due to disabled meter / gauge system) All systems that the converter supplies power to do not operate (see circuit diagram) A
      P323A-00
      P323A-16
      P323B-29
      P323B-38
      The audio does not operate (until the ignition 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 ignition switch is turned off) - Does not blink If overcurrent is detected in the audio and visual system, system operation is disabled while the ignition switch is ON (Returns to normal when the ignition switch is turned off) C
      The external backup boost converter (eco run vehicle converter assembly) output side system does not operate
      • Audio and visual system
      • Open in ECU-ACC fuse circuit
      • Malfunction in circuits the converter supplies power to
      • External backup boost converter (eco run vehicle converter assembly) malfunction
      		 - - Does not blink All systems that the converter supplies power to do not operate (see circuit diagram) D
      • The combination meter assembly cannot be turned off (short between IG12 and +B)
      HINT: Varies depending on the number of times an open occurs in the +B circuit      		 Converter circuit malfunction
      • Short between IG12 and +B
      		 - - Does not blink The converter cannot shut off the power source when the ignition switch is turned off B
      • Ignition switch cannot be turned off from ACC (short between ACC and +B)
      • Ignition switch cannot be turned off from ON (short between IGP or IGR and +B)
      		 Engine stop and start ECU power source circuit malfunction
      • Short between ACC and +B
      • Short between IGP and +B
      • Short between IGR and +B
      		 - - Does not blink
      • Ignition switch does not turn ACC
      • Ignition switch cannot be turned off
      		 B

      Result

      Proceed to
      A
      B
      C
      D
      E

    Result: 

    A 

    GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [10/2022 - 11/2023] 

    Result: 

    C 

    See step  5

    Result: 

    D 

    See step  7

    Result: 

    E 

    See step  13

    Result: 

    B 

    See step  2

  2. CHECK ENGINE STOP AND START ECU (POWER SOURCE CIRCUIT) 
    1. 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
      A33-1 (BIN2) - Body ground Always 9.5 to 14 V
      A33-3 (BIN1) - Body ground Always 9.5 to 14 V
    3. Turn the ignition switch to ACC.
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      H66-19 (ACC) - Body ground Ignition switch ACC 9.5 to 14 V
    5. Turn the ignition switch to ON.
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      H66-21 (IGR) - Body ground Ignition switch ON 9.5 to 14 V
      H66-18 (IGP) - Body ground Ignition switch ON 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
      H66-20 (ILL) - Body ground Headlight dimmer switch (light control switch) in tail or head position 9.5 to 14 V
    9. Turn the headlight dimmer switch (light control switch) to off.
    10. Turn the ignition switch off.
    11. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      H66-21 (IGR) - Body ground Ignition switch off 0 to 1 V
      H66-19 (ACC) - Body ground Ignition switch off 0 to 1 V
      H66-18 (IGP) - Body ground Ignition switch off 0 to 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  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

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - M51-1 (IG) Always Below 1 Ω
      H66-2 (B41) - M51-7 (+B) Always Below 1 Ω
      H66-3 (IG41) - Body ground Always 10 kΩ or higher
      M51-1 (IG) - Body ground Always 10 kΩ or higher
      H66-2 (B41) - Body ground Always 10 kΩ or higher
      M51-7 (+B) - Body ground Always 10 kΩ or higher
      METER MIRROR SUB-ASSEMBLY (W/ HEADUP DISPLAY SYSTEM)

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - H31-1 (IG) Always Below 1 Ω
      H66-2 (B41) - H31-2 (B) Always Below 1 Ω
      H66-3 (IG41) - Body ground Always 10 kΩ or higher
      H31-1 (IG) - Body ground Always 10 kΩ or higher
      H66-2 (B41) - Body ground Always 10 kΩ or higher
      H31-2 (B) - Body ground Always 10 kΩ or higher
      CLEARANCE WARNING ECU ASSEMBLY (W/ INTUITIVE PARKING ASSIST SYSTEM)

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - H46-1 (IG) Always Below 1 Ω
      H66-3 (IG41) - Body ground Always 10 kΩ or higher
      H46-1 (IG) - Body ground Always 10 kΩ or higher
      INNER REAR VIEW MIRROR ASSEMBLY

      Tester Connection Condition Specified Condition
      H66-11 (B43) - R1-6 (+B)*1 Always Below 1 Ω
      H66-11 (B43) - R1-6 (B)*2 Always Below 1 Ω
      H66-3 (IG41) - R1-1 (IG) Always Below 1 Ω
      H66-11 (B43) - Body ground Always 10 kΩ or higher
      R1-6 (+B) - Body ground Always 10 kΩ or higher
      H66-3 (IG41) - Body ground Always 10 kΩ or higher
      R1-1 (IG) - Body ground Always 10 kΩ or higher

      *1: w/o Digital Inner Mirror

      *2: w/ Digital Inner Mirror

      POWER STEERING ECU (RACK AND PINION POWER STEERING GEAR ASSEMBLY)

      Tester Connection Condition Specified Condition
      H66-23 (IG31) - C67-4 (IG) Always Below 1 Ω
      H66-23 (IG31) - Body ground Always 10 kΩ or higher
      C67-4 (IG) - Body ground Always 10 kΩ or higher
      SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)

      Tester Connection Condition Specified Condition
      H66-23 (IG31) - A39-45 (IG1) Always Below 1 Ω
      H66-23 (IG31) - Body ground Always 10 kΩ or higher
      A39-45 (IG1) - Body ground Always 10 kΩ or higher
      COMBINATION METER ASSEMBLY (FOR 12.3 INCH MULTI-DISPLAY TYPE)

      Tester Connection Condition Specified Condition
      H66-10 (IG12) - H112-39 (IG+) Always Below 1 Ω
      H66-10 (IG12) - Body ground Always 10 kΩ or higher
      H112-39 (IG+) - Body ground Always 10 kΩ or higher
      COMBINATION METER ASSEMBLY (FOR 8 INCH MULTI-DISPLAY TYPE)

      Tester Connection Condition Specified Condition
      H66-10 (IG12) - H21-6 (IG+) Always Below 1 Ω
      H66-10 (IG12) - Body ground Always 10 kΩ or higher
      H21-6 (IG+) - Body ground Always 10 kΩ or higher
      FOG LIGHT ASSEMBLY (W/ FRONT FOG LIGHT)

      Tester Connection Condition Specified Condition
      H66-2 (B41) - 2 (FOG FR relay) Always Below 1 Ω
      H66-2 (B41) - 5 (FOG FR relay) Always Below 1 Ω
      H66-2 (B41) or 2 (FOG FR relay) - Body ground Always 10 kΩ or higher
      H66-2 (B41) or 5 (FOG FR relay) Always 10 kΩ or higher
      BLIND SPOT MONITOR SENSOR LH

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - M43-5 (BLB) Always Below 1 Ω
      H66-3 (IG41) or M43-5 (BLB) - Body ground and other terminals Always 10 kΩ or higher
      BLIND SPOT MONITOR SENSOR RH

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - M2-5 (BRB) Always Below 1 Ω
      H66-3 (IG41) or M2-5 (BRB) - Body ground and other terminals Always 10 kΩ or higher
      CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - H59-11 (IG1) Always Below 1 Ω
      H66-3 (IG41) or H59-11 (IG1) - Body ground and other terminals Always 10 kΩ or higher
      AIR CONDITIONING CONTROL ASSEMBLY

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - H27-6 (IG+) Always Below 1 Ω
      H66-3 (IG41) or H27-6 (IG+) - Body ground and other terminals Always 10 kΩ or higher
      NO. 2 AIR CONDITIONING CONTROL ASSEMBLY

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - T2-9 (IG) Always Below 1 Ω
      H66-3 (IG41) or T2-9 (IG) - Body ground and other terminals Always 10 kΩ or higher
      MILLIMETER WAVE RADAR SENSOR ASSEMBLY

      Tester Connection Condition Specified Condition
      H66-3 (IG41) - B6-8 (IGB) Always Below 1 Ω
      H66-3 (IG41) or B6-8 (IGB) - Body ground and other terminals Always 10 kΩ or higher
      RADIO RECEIVER ASSEMBLY

      Tester Connection Condition Specified Condition
      H66-12 (B42) - F107-4 (+B1) Always Below 1 Ω
      H66-12 (B42) or F107-4 (+B1) - Body ground and other terminal Always 10 kΩ or higher
      FRONT DOOR AMBIENT LIGHT LH (FRONT DOOR TRIM BOARD SUB-ASSEMBLY LH) (W/ AMBIENT ILLUMINATION LIGHT)

      Tester Connection Condition Specified Condition
      H66-11 (B43) - J26-2 (+) Always Below 1 Ω
      H66-11 (B43) or J26-2 (+) - Body ground and other terminals Always 10 kΩ or higher
      FRONT DOOR AMBIENT LIGHT RH (FRONT DOOR TRIM BOARD SUB-ASSEMBLY RH) (W/ AMBIENT ILLUMINATION LIGHT)

      Tester Connection Condition Specified Condition
      H66-11 (B43) - J10-2 (+) Always Below 1 Ω
      H66-11 (B43) or J10-2 (+) - Body ground and other terminals Always 10 kΩ or higher
      REAR DOOR AMBIENT LIGHT LH (REAR DOOR TRIM BOARD SUB-ASSEMBLY LH) (W/ AMBIENT ILLUMINATION LIGHT)

      Tester Connection Condition Specified Condition
      H66-11 (B43) - K10-2 (+) Always Below 1 Ω
      H66-11 (B43) or K10-2 (+) - Body ground and other terminals Always 10 kΩ or higher
      REAR DOOR AMBIENT LIGHT RH (REAR DOOR TRIM BOARD SUB-ASSEMBLY RH) (W/ AMBIENT ILLUMINATION LIGHT)

      Tester Connection Condition Specified Condition
      H66-11 (B43) - K5-2 (+) Always Below 1 Ω
      H66-11 (B43) or K5-2 (+) - Body ground and other terminals Always 10 kΩ or higher
      NO. 1 INTERIOR ILLUMINATION LIGHT ASSEMBLY

      Tester Connection Condition Specified Condition
      H66-11 (B43) - H68-2 (+) Always Below 1 Ω
      H66-11 (B43) or H68-2 (+) - Body ground Always 10 kΩ or higher
      NO. 2 INTERIOR ILLUMINATION LIGHT ASSEMBLY

      Tester Connection Condition Specified Condition
      H66-11 (B43) - H69-2 (+) Always Below 1 Ω
      H66-11 (B43) or H69-2 (+) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  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.

      HINT: 

      Measure the voltage at the corresponding terminals.

      Standard Voltage

      Tester Connection Condition Specified Condition
      M51-7 (+B) - Body ground Always 10.5 to 16 V
      J26-2 (+) - Body ground Always 10.5 to 16 V
      J10-2 (+) - Body ground Always 10.5 to 16 V
      K10-2 (+) - Body ground Always 10.5 to 16 V
      K5-2 (+) - Body ground Always 10.5 to 16 V
      H68-2 (ILL+) - Body ground Always 10.5 to 16 V
      H69-2 (ILL+) - Body ground Always 10.5 to 16 V
      R1-6 (+B)*1 - Body ground Always 10.5 to 16 V
      R1-6 (B)*2 - Body ground Always 10.5 to 16 V
      H31-2 (B) - Body ground Always 10.5 to 16 V
      5 (FOG FR relay)*3 - Body ground Always 10.5 to 16 V
      H11-1 (+B) - Body ground Always 10.5 to 16 V
      H31-2 (B) - Body ground Always 10.5 to 16 V
      H8-1 (B) - Body ground Always 10.5 to 16 V
      H107-4 (+B1) - Body ground Always 10.5 to 16 V

      *1: w/o Digital Inner Mirror

      *2: w/ Digital Inner Mirror

      *3: w/ Front Fog Light

    3. Turn the ignition switch to ON.
    4. Measure the voltage according to the value(s) in the table below.

      HINT: 

      Measure the voltage at the corresponding terminals.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A39-45 (IG1) - Body ground Ignition switch ON 10.5 to 16 V
      C67-4 (IG) - Body ground Ignition switch ON 10.5 to 16 V
      M43-5 (BLB) - Body ground Ignition switch ON 10.5 to 16 V
      M2-5 (BRB) - Body ground Ignition switch ON 10.5 to 16 V
      M51-1 (IG) - Body ground Ignition switch ON 10.5 to 16 V
      R1-1 (IG) - Body ground Ignition switch ON 10.5 to 16 V
      H59-11 (IG1) - Body ground Ignition switch ON 10.5 to 16 V
      H27-6 (IG+) - Body ground Ignition switch ON 10.5 to 16 V
      T2-9 (IG) - Body ground Ignition switch ON 10.5 to 16 V
      H46-1 (IG) - Body ground Ignition switch ON 10.5 to 16 V
      H31-1 (IG) - Body ground Ignition switch ON 10.5 to 16 V
      B6-8 (IGB) - Body ground Ignition switch ON 10.5 to 16 V
      H112-39 (IG+) - Body ground Ignition switch ON 10.5 to 16 V
      H21-6 (IG+) - Body ground Ignition switch ON 10.5 to 16 V
    5. Turn the light control switch to the tail or head position.
    6. Measure the voltage according to the value(s) in the table below.

      HINT: 

      Measure the voltage at the corresponding terminals.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      H27-5 (ILL+) - Body ground Light control switch in tail or head position 10.5 to 16 V
      H27-1 (ILL+) - Body ground Light control switch in tail or head position 10.5 to 16 V
      T2-10 (ILL+) - Body ground Light control switch in tail or head position 10.5 to 16 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK POWER SOURCE CIRCUIT (POWER SOURCE CIRCUIT OF RELATED SYSTEM) 

    Result: 

    NG 

    REPLACE ENGINE STOP AND START ECU 

    Refer to REMOVAL [10/2022 - 11/2023]

  5. CHECK AUDIO AND VISUAL SYSTEM 
    1. Turn the ignition switch off and wait for 1 minute.
    2. Turn the ignition switch to 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

    Result: 

    OK 

    END 

    Result: 

    NG 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - STEREO COMPONENT AMPLIFIER ASSEMBLY) 
    1. Disconnect the engine stop and start ECU connector.
    2. Disconnect the stereo component amplifier assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A18-5 (BO1), M37-1 (+B) or M37-16 (+B2) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO AUDIO AND VISUAL SYSTEM 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. CHECK HARNESS AND CONNECTOR (BIN TERMINAL POWER SOURCE CIRCUIT) 
    1. Disconnect the external backup boost converter (eco run vehicle converter assembly) connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A18-11 (BIN) - Body ground Always 9.5 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EXTERNAL BACKUP BOOST CONVERTER (ECO RUN VEHICLE CONVERTER ASSEMBLY) - BATTERY) 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (ACC TERMINAL POWER SOURCE CIRCUIT) 
    1. Disconnect the external backup boost converter (eco run vehicle converter assembly) connector.
    2. Turn the ignition switch to ACC.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A18-3 (ACC) - Body ground Ignition switch ACC 9.5 to 14 V
    4. Turn the ignition switch off.
    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A18-3 (ACC) - Body ground Ignition switch off 0 to 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (EXTERNAL BACKUP BOOST CONVERTER (ECO RUN VEHICLE CONVERTER ASSEMBLY) - BODY GROUND) 
    1. Disconnect the external backup boost converter (eco run vehicle converter assembly) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A18-6 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (EXTERNAL BACKUP BOOST CONVERTER (ECO RUN VEHICLE CONVERTER ASSEMBLY) - EACH ECU OR SENSOR) 
    1. Disconnect the external backup boost converter (eco run vehicle converter assembly) connector.
    2. Disconnect the connector from the corresponding system ECU/sensor.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A18-5 (BO1) - M37-1 (+B) Always Below 1 Ω
      A18-5 (BO1) - M37-16 (+B2) Always Below 1 Ω
      A18-5 (BO1) or M37-1 (+B) or M37-16 (+B2) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK EXTERNAL BACKUP BOOST CONVERTER (ECO RUN VEHICLE CONVERTER ASSEMBLY) (OUTPUT VOLTAGE FOR EACH SYSTEM) 
    1. Disconnect the connector from the corresponding system ECU/sensor.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      M37-1 (+B) - Body ground Always 10.5 to 16 V
      M37-16 (+B2) - Body ground Always 10.5 to 16 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO AUDIO AND VISUAL SYSTEM 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ]

    Result: 

    NG 

    REPLACE EXTERNAL BACKUP BOOST CONVERTER (ECO RUN VEHICLE CONVERTER ASSEMBLY) 

    Refer to REMOVAL [10/2022 - 11/2023]

  12. CHECK HARNESS AND CONNECTOR (EXTERNAL BACKUP BOOST CONVERTER (ECO RUN VEHICLE CONVERTER ASSEMBLY) - POWER DISTRIBUTION BOX ASSEMBLY) 
    1. Disconnect the external backup boost converter (eco run vehicle converter assembly) connector.
    2. Disconnect the power distribution box assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A18-3 (ACC) - 4A-40 Always Below 1 Ω
      A18-3 (ACC) or 4A-40 - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  13. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BBC NO. 1 FUSE AND BBC NO. 2 FUSE) 
    1. Disconnect the engine stop and start ECU connector.
    2. Remove the BBC NO. 1 fuse and BBC NO. 2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A33-1 (BIN2) - 2 (BBC NO. 2 fuse) Always Below 1 Ω
      A33-3 (BIN1) - 2 (BBC NO. 1 fuse) Always Below 1 Ω
      A33-1 (BIN2) or 2 (BBC NO. 2 fuse) - Body ground and other terminals Always 10 kΩ or higher
      A33-3 (BIN1) or 2 (BBC NO. 1 fuse) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - EACH ECU OR SENSOR) 
    1. Disconnect the engine stop and start ECU connector.
    2. Remove the FOG FR relay from the No. 1 engine room relay block and No. 1 junction block assembly. (w/ Front Fog Light)
    3. Disconnect the integration control sub-assembly connector. (w/ 12.3 Inch Display)
    4. Disconnect the tire pressure warning ECU and receiver connector.
    5. Disconnect the navigation ECU connector. (w/ Navigation System)
    6. Disconnect the meter mirror assembly connector. (w/ Headup Display)
    7. Disconnect the radio and display receiver assembly connector. (w/o 12.3 Inch Display)
    8. Disconnect the radio receiver assembly connector. (w/ 12.3 Inch Display)
    9. Disconnect the multi-display assembly connector. (w/ 12.3 Inch Display)
    10. Disconnect the television display assembly connector. (w/ Rear Seat Entertainment System)
    11. Disconnect the inner rear view mirror assembly connector. (w/ EC Mirror or Digital Inner Mirror)
    12. Disconnect the front door ambient light LH (front door trim board sub-assembly LH) connector. (w/ Ambient Illumination Light)
    13. Disconnect the front door ambient light RH (front door trim board sub-assembly RH) connector. (w/ Ambient Illumination Light)
    14. Disconnect the rear door ambient light LH (rear door trim board sub-assembly LH) connector. (w/ Ambient Illumination Light)
    15. Disconnect the rear door ambient light RH (rear door trim board sub-assembly RH) connector. (w/ Ambient Illumination Light)
    16. Disconnect the front passenger side tray illumination light (No. 1 instrument panel light sub-assembly) connector. (w/ Ambient Illumination Light)
    17. Disconnect the center tray illumination light (No. 1 instrument panel light sub-assembly) connector. (w/ Ambient Illumination Light)
    18. Disconnect the air conditioning control assembly connector.
    19. Disconnect the central gateway ECU (network gateway ECU) connector.
    20. Disconnect the millimeter wave radar sensor assembly connector.
    21. Disconnect the clearance warning ECU assembly connector. (w/ Intuitive Parking Assist System)
    22. Disconnect the blind spot monitor sensor LH connector.
    23. Disconnect the blind spot monitor sensor RH connector.
    24. Disconnect the No. 2 air conditioning control assembly connector.
    25. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H66-2 (B41) - 2 (FOG FR relay)*1 Always Below 1 Ω
      H66-2 (B41) - 5 (FOG FR relay)*1 Always Below 1 Ω
      H66-2 (B41) - H8-1 (B)*3 Always Below 1 Ω
      H66-2 (B41) - M51-7 (+B) Always Below 1 Ω
      H66-2 (B41) - H18-10 (+B)*2 Always Below 1 Ω
      H66-2 (B41) - H31-2 (B)*5 Always Below 1 Ω
      H66-12 (B42) - H1-4 (+B1)*4 Always Below 1 Ω
      H66-12 (B42) - H4-4 (+B1)*3 Always Below 1 Ω
      H66-11 (B43) - H7-12 (B)*3 Always Below 1 Ω
      H66-11 (B43) - R16-1 (+B)*6 Always Below 1 Ω
      H66-11 (B43) - R1-6 (B)*7 Always Below 1 Ω
      H66-11 (B43) - R1-6 (+B)*8 Always Below 1 Ω
      H66-11 (B43) -J26-2 (+)*10 Always Below 1 Ω
      H66-11 (B43) -J10-2 (+)*10 Always Below 1 Ω
      H66-11 (B43) -K10-2 (+)*10 Always Below 1 Ω
      H66-11 (B43) -K5-2 (+)*10 Always Below 1 Ω
      H66-11 (B43) -H69-2 (ILL+)*10 Always Below 1 Ω
      H66-11 (B43) -H68-2 (ILL+)*10 Always Below 1 Ω
      H66-3 (IG41) - H8-4 (IG+)*3 Always Below 1 Ω
      H66-3 (IG41) - R1-1 (IG)*9 Always Below 1 Ω
      H66-3 (IG41) - M51-1 (IG) Always Below 1 Ω
      H66-3 (IG41) - H31-1 (IG)*5 Always Below 1 Ω
      H66-3 (IG41) - H27-4 (IG+)*3 Always Below 1 Ω
      H66-3 (IG41) - H27-6 (IG+)*4 Always Below 1 Ω
      H66-3 (IG41) - H59-11 (IG1) Always Below 1 Ω
      H66-3 (IG41) - B6-8 (IGB) Always Below 1 Ω
      H66-3 (IG41) - H46-1 (IG) Always Below 1 Ω
      H66-3 (IG41) - M43-5 (BLB) Always Below 1 Ω
      H66-3 (IG41) - M2-5 (BRB) Always Below 1 Ω
      H66-3 (IG41) - T2-9 (IG) Always Below 1 Ω
      H66-2 (B41) or 2 (FOG FR relay)*1 - Body ground and other terminals Always 10 kΩ or higher
      H66-2 (B41) or 5 (FOG FR relay)*1 - Body ground and other terminals Always 10 kΩ or higher
      H66-2 (B41) or H8-1 (B)*3 - Body ground and other terminals Always 10 kΩ or higher
      H66-2 (B41) or M51-7 (+B) - Body ground and other terminals Always 10 kΩ or higher
      H66-2 (B41) or H18-10 (+B)*2 - Body ground and other terminals Always 10 kΩ or higher
      H66-2 (B41) or H31-2 (B)*5 - Body ground and other terminals Always 10 kΩ or higher
      H66-12 (B42) or H1-4 (+B1)*4 - Body ground and other terminals Always 10 kΩ or higher
      H66-12 (B42) or H4-4 (+B1)*3 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or H7-12 (B)*3 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or R16-1 (+B)*6 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or R1-6 (B)*7 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or R1-6 (+B)*8 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or J26-2 (+)*10 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or J10-2 (+)*10 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or K10-2 (+)*10 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or K5-2 (+)*10 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or H69-2 (ILL+)*10 - Body ground and other terminals Always 10 kΩ or higher
      H66-11 (B43) or H68-2 (ILL+)*10 - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or H8-4 (IG+)*3 - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or R1-1 (IG)*9 - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or M51-1 (IG) - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or H31-1 (IG)*5 - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or H27-4 (IG+)*3 - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or H27-6 (IG+)*4 - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or H59-11 (IG1) - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or B6-8 (IGB) - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or H46-1 (IG) - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or M43-5 (BLB) - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or M2-5 (BRB) - Body ground and other terminals Always 10 kΩ or higher
      H66-3 (IG41) or T2-9 (IG) - Body ground and other terminals Always 10 kΩ or higher
      1. *1: w/ Front Fog Light
      2. *2: w/ Navigation System
      3. *3: w/ 12.3 Inch Display
      4. *4: w/o 12.3 Inch Display
      5. *5: w/ Headup Display
      6. *6: w/ Rear Seat Entertainment System
      7. *7: w/ Digital Inner Mirror
      8. *8: w/ EC Mirror
      9. *9: w/ EC Mirror or Digital Inner Mirror
      10. *10: w/ Ambient Illumination Light

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  15

  15. CHECK ENGINE STOP AND START ECU 
    GTY852847Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component without harness connected
    (Engine Stop and Start ECU)    		 - -
    1. Disconnect the engine stop and start ECU connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H66-2 (B41) - A34-6 (DGND) Always 10 kΩ or higher
      H66-3 (IG41) - A34-6 (DGND) Always 10 kΩ or higher
      H66-11 (B43) - A34-6 (DGND) Always 10 kΩ or higher
      H66-12 (B42) - A34-6 (DGND) Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ENGINE STOP AND START ECU 

    Refer to REMOVAL [10/2022 - 11/2023]

    Result: 

    OK 

    See step  16

  16. CHECK VEHICLE CONDITION (B41, B42, B43 OR IG41 CIRCUIT) 
    1. Check that additional devices installed to the vehicle (aftermarket audio system, etc.) are not connected to the B41, B42, B43 or IG41 terminal circuit of the engine stop and start ECU.

      Result

      Result Proceed to
      Load from an additional device installed to the vehicle (aftermarket audio system, etc.) is not applied. A
      Load from an additional device installed to the vehicle (aftermarket audio system, etc.) is applied. B

    Result: 

    A 

    TROUBLESHOOT ECUS CONNECTED TO TERMINALS B41, B42, B43 AND IG41 

    Result: 

    B 

    END (REMOVE ADDITIONAL DEVICE) 

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