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Home >> Lexus >> 2019 >> RC F >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Exterior Lights >> Lighting System (Triple Beam) - Diagnostic Codes & Circuit Tests >> LIGHTING SYSTEM(for Triple Beam Headlight) >> Power Source Circuit [09/2014 - 03/2019] >> Procedure

Power Source Circuit [09/2014 - 03/2019]: Procedure

  1. CHECK HARNESS AND CONNECTOR (HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY - BATTERY AND BODY GROUND) 
    1. Disconnect the A3 headlight light control ECU sub-assembly LH connector.
    2. Disconnect the A11 headlight light control ECU sub-assembly RH connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY LH SIDE

      Tester Connection Condition Specified Condition
      A3-13 (ECUB) - Body ground Light control switch in tail or head position 11 to 14 V
      A3-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY RH SIDE

      Tester Connection Condition Specified Condition
      A11-13 (ECUB) - Body ground Light control switch in tail or head position 11 to 14 V
      A11-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY LH SIDE

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

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

      Result

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

    Result: 

    A 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [09/2014 - 03/2019] 

    Result: 

    C 

    See step  7

    Result: 

    B 

    See step  2

  2. INSPECT H-LP LH RELAY 
    1. Remove the H-LP LH relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Inspect the H-LP LH relay.

      Refer to ON-VEHICLE INSPECTION [09/2014 - 03/2019]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE H-LP LH RELAY 

    Result: 

    OK 

    See step  3

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      Relay terminal 1 - Body ground Always 11 to 14 V
      Relay terminal 3 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - HEADLIGHT LIGHT CONTROL 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 5 - A3-13 (ECUB) Always Below 1 Ω
      Relay terminal 5 - 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 - 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
      Relay terminal 2 - 4C-29 Always Below 1 Ω
      Relay terminal 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  6

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

      Refer to REMOVAL [09/2014 - ]

    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.
      GTY510856Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Instrument Panel Junction Block Assembly)      		 - -

      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 - ] 

  7. INSPECT H-LP RH/MIR HTR RELAY 
    1. Remove the H-LP RH/MIR HTR relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Inspect the H-LP RH/MIR HTR relay.

      Refer to ON-VEHICLE INSPECTION [09/2014 - 03/2019]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE H-LP RH/MIR HTR RELAY 

    Result: 

    OK 

    See step  8

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      Relay terminal 1 - Body ground Always 11 to 14 V
      Relay terminal 3 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (H-LP RH/MIR HTR RELAY - HEADLIGHT LIGHT CONTROL 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 5 - A11-13 (ECUB) Always Below 1 Ω
      Relay terminal 5 - 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/MIR HTR 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
      Relay terminal 2 - O2-1 (DIM) Always Below 1 Ω
      Relay terminal 2 - 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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