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Power Source Circuit [10/2015 - 08/2019]: Procedure

  1. CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY - POWER SOURCE AND BODY GROUND) 
    1. Disconnect the A49 headlight ECU sub-assembly LH connector.
    2. Disconnect the A50 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
      A49-13 (ECUB) - Body ground Power switch on (IG) 11 to 14 V
      A49-4 (IG) - Body ground Power switch on (IG) 11 to 14 V
      HEADLIGHT ECU SUB-ASSEMBLY RH

      Tester Connection Condition Specified Condition
      A50-13 (ECUB) - Body ground Power switch on (IG) 11 to 14 V
      A50-4 (IG) - Body ground Power switch on (IG) 11 to 14 V
    4. Measure the resistance according to the value (s) in the table below.

      Standard Resistance

      HEADLIGHT ECU SUB-ASSEMBLY LH

      Tester Connection Condition Specified Condition
      A49-12 (GND) - Body ground Always Below 1 Ω
      HEADLIGHT ECU SUB-ASSEMBLY RH

      Tester Connection Condition Specified Condition
      A50-12 (GND) - Body ground Always Below 1 Ω

      Result

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

    Result: 

    A 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [10/2015 - 12/2017]  , or refer to  PROBLEM SYMPTOMS TABLE [12/2017 - 03/2018]  , or refer to  PROBLEM SYMPTOMS TABLE [03/2018 - 08/2019] 

    Result: 

    C 

    See step  7

    Result: 

    B 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE - H-LP LH RELAY) 
    1. Remove the H-LP LH relay from the engine room relay block and junction block assembly.
    2. Measure the voltage according to the value (s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      Relay terminal 1 - Body ground Power switch off 11 to 14 V
      Relay terminal 5 - Body ground Power switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

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

      Refer to ON-VEHICLE INSPECTION [10/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE H-LP LH RELAY 

    Result: 

    OK 

    See step  4

  4. 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
      Relay terminal 3 - A49-13 (ECUB) Always Below 1 Ω
      Relay terminal 3 or A49-13 (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  5

  5. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 
    1. Disconnect the 2C 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
      Relay terminal 2 - 2C-31 Always Below 1 Ω
      Relay terminal 2 or 2C-31 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 
    1. Remove the instrument panel junction block assembly.

      Refer to REMOVAL [10/2015 - 08/2016] , or refer to REMOVAL [08/2016 - 03/2018] , or refer to REMOVAL [03/2018 - 08/2019]

    2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
    3. Measure the resistance according to the value (s) in the table below.
      GTY669021Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Instrument Panel Junction Block Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      2C-31 - 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 [10/2015 - 08/2016]  , or refer to  REMOVAL [08/2016 - 03/2018]  , or refer to  REMOVAL [03/2018 - 08/2019] 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [10/2015 - 08/2016]  , or refer to  REMOVAL [08/2016 - 03/2018]  , or refer to  REMOVAL [03/2018 - 08/2019] 

  7. CHECK HARNESS AND CONNECTOR (POWER SOURCE - H-LP RH RELAY) 
    1. Remove the H-LP RH relay from the engine room relay block and junction block assembly.
    2. Measure the voltage according to the value (s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      Relay terminal 1 - Body ground Power switch off 11 to 14 V
      Relay terminal 5 - Body ground Power switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

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

      Refer to ON-VEHICLE INSPECTION [10/2015 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE H-LP RH RELAY 

    Result: 

    OK 

    See step  9

  9. 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
      Relay terminal 3 - A50-13 (ECUB) Always Below 1 Ω
      Relay terminal 3 or A50-13 (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  10

  10. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 
    1. Disconnect the J8 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
      Relay terminal 2 - J8-1 (DIM) Always Below 1 Ω
      Relay terminal 2 or J8-1 (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 [10/2015 - 08/2016]  , or refer to  REMOVAL [08/2016 - 03/2018]  , or refer to  REMOVAL [03/2018 - 08/2019] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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