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Power Source Circuit [03/2019 - ]: Procedure

  1. INSPECT HEADLIGHT ECU SUB-ASSEMBLY (ECUB TERMINAL VOLTAGE) 
    GTY961383Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 Headlight ECU Sub-assembly LH
    *2 Headlight ECU Sub-assembly RH
    *a Component without harness connected
    (Headlight ECU Sub-assembly)
    1. Disconnect the A3 headlight ECU sub-assembly LH connector.
    2. Disconnect the A11 headlight ECU sub-assembly RH connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      HEADLIGHT ECU SUB-ASSEMBLY LH

      Tester Connection Condition Specified Condition
      A3-13 (ECUB) - Body ground Engine switch on (IG) or light control switch in tail or head position 11 to 14 V
      HEADLIGHT ECU SUB-ASSEMBLY RH

      Tester Connection Condition Specified Condition
      A11-13 (ECUB) - Body ground Engine switch on (IG) or light control switch in tail or head position 11 to 14 V

      Result

      Result Proceed to
      OK A
      NG (Headlight ECU Sub-assembly LH) B
      NG (Headlight ECU Sub-assembly RH) C

    Result: 

    B 

    See step  4

    Result: 

    C 

    See step  9

    Result: 

    A 

    See step  2

  2. INSPECT HEADLIGHT ECU SUB-ASSEMBLY (IG TERMINAL VOLTAGE) 
    GTY961382Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 Headlight ECU Sub-assembly LH
    *2 Headlight ECU Sub-assembly RH
    *a Component without harness connected
    (Headlight ECU Sub-assembly)
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      HEADLIGHT ECU SUB-ASSEMBLY LH

      Tester Connection Condition Specified Condition
      A3-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      HEADLIGHT ECU SUB-ASSEMBLY RH

      Tester Connection Condition Specified Condition
      A11-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      HEADLIGHT ECU SUB-ASSEMBLY LH

      Tester Connection Condition Specified Condition
      A3-12 (GND) - Body ground Always Below 1 Ω
      HEADLIGHT ECU SUB-ASSEMBLY RH

      Tester Connection Condition Specified Condition
      A11-12 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [03/2019 - 01/2023]  , or refer to  PROBLEM SYMPTOMS TABLE [01/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  4. INSPECT H-LP LH RELAY 
    1. Inspect the H-LP LH relay.

      Refer to ON-VEHICLE INSPECTION [03/2019 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE H-LP LH RELAY 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (BATTERY - H-LP LH RELAY) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      1 (H-LP LH relay) - Body ground Always 11 to 14 V
      3 (H-LP LH relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - HEADLIGHT ECU SUB-ASSEMBLY LH) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      5 (H-LP LH relay) - A3-13 (ECUB) Always Below 1 Ω
      5 (H-LP LH relay) or A3-13 (ECUB) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) 
    1. Disconnect the 4C instrument panel junction block assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (H-LP LH relay) - 4C-29 Always Below 1 Ω
      2 (H-LP LH relay) or 4C-29 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 
    GTY669025Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Component without harness connected
    (Instrument Panel Junction Block Assembly)    		 - -
    1. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

      Refer to REMOVAL [09/2014 - ]

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      4C-29 - MB-15 (HRLY) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

  9. INSPECT H-LP RH RELAY 
    1. Inspect the H-LP RH relay.

      Refer to ON-VEHICLE INSPECTION [03/2019 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE H-LP RH RELAY 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (BATTERY - H-LP RH RELAY) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      1 (H-LP RH relay) - Body ground Always 11 to 14 V
      3 (H-LP RH relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - HEADLIGHT ECU SUB-ASSEMBLY RH) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      5 (H-LP RH relay) - A11-13 (ECUB) Always Below 1 Ω
      5 (H-LP RH relay) or A11-13 (ECUB) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 
    1. Disconnect the O2 main body ECU (multiplex network body ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (H-LP RH relay) - O2-1 (DIM) Always Below 1 Ω
      2 (H-LP RH relay) or O2-1 (DIM) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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