LIGHTING SYSTEM Power Source Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives IG signals and supplies power to the headlight light control ECU sub-assembly via the H-LP relay.

WIRING DIAGRAM

B008HXLE01

CAUTION / NOTICE / HINT

Note


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

  • If the main body ECU (multiplex network body ECU) is replaced, refer to the Service Bulletin.

  • As the door control battery is installed between the vehicle battery and main body ECU (multiplex network body ECU), first perform the inspections in On-Vehicle Inspection to confirm that there are no malfunctions in the power source circuit for the main body ECU (multiplex network body ECU) before performing this troubleshooting procedure.*

    *: w/ Door Control Battery

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY - BATTERY AND BODY GROUND)


    1. B008HUOC08
      *A Headlight light control ECU sub-assembly LH
      *B Headlight light control ECU sub-assembly RH
      *a

      Front view of wire harness connector

      (Headlight light control ECU sub-assembly)

      Disconnect the A19 headlight light control ECU sub-assembly LH or A20 headlight light control ECU sub-assembly RH connector.

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

      Standard Voltage
      Headlight light control ECU sub-assembly LH
      Tester Connection Switch Condition Specified Condition
      A19-13 (ECUB) - Body ground Headlight on 11 to 14 V
      A19-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      Headlight light control ECU sub-assembly RH
      Tester Connection Switch Condition Specified Condition
      A20-13 (ECUB) - Body ground Headlight on 11 to 14 V
      A20-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V

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

      Standard Resistance
      Headlight light control ECU sub-assembly LH
      Tester Connection Condition Specified Condition
      A19-12 (GND) - Body ground Always Below 1 Ω
      Headlight light control ECU sub-assembly RH
      Tester Connection Condition Specified Condition
      A20-12 (GND) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK A
      NG (Headlight Light Control ECU Sub-assembly LH) B
      NG (Headlight Light Control ECU Sub-assembly RH) C

    A

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    C

    CHECK HEADLIGHT RELAY (H-LP RH) Click here

    B

  2. INSPECT HEADLIGHT DIMMER RELAY (H-LP LH/DIMMER [HI])


    1. Remove the headlight light dimmer relay (H-LP LH/DIMMER [HI]) from the engine room relay block.

    2. Inspect the headlight light dimmer relay (H-LP LH/DIMMER [HI]).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT DIMMER RELAY (H-LP LH/DIMMER [HI])

    OK

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY [H-LP LH/DIMMER (HI)] - BATTERY)


    1. B008HEGC02
      *a

      Front view of wire harness connector

      (to Headlight Light Dimmer Relay (H-LP LH/DIMMER [HI]))

      Remove the headlight light dimmer relay (H-LP LH/DIMMER [HI]) from the engine room relay block.

    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 Always 11 to 14 V
      Relay terminal 5 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY [H-LP LH/DIMMER (HI)] - HEADLIGHT LIGHT CONTROL ECU SUB-ASSEMBLY LH)


    1. Remove the headlight light dimmer relay (H-LP LH/DIMMER [HI]) from the engine room relay block.

    2. Disconnect the A19 headlight light control ECU LH sub-assembly LH connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 3 - A19-13 (ECUB) Always Below 1 Ω
      Relay terminal 3 or A19-13 (ECUB) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY [H-LP LH/DIMMER (HI)] - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU])


    1. Remove the headlight light dimmer relay (H-LP LH/DIMMER [HI]) from the engine room relay block.

    2. Remove the instrument panel junction block assembly.

      for LHD:

      Click here

      for RHD:

      Click here

    3. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

      for LHD:

      Click here

      for RHD:

      Click here

    4. Disconnect the 4B instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 2 - A-15 (HRLY) Always Below 1 Ω
      Relay terminal 2 or A-15 (HRLY) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here
    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for RHD: REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    NG

  6. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY [H-LP LH/DIMMER (HI)] - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. Remove the headlight light dimmer relay (H-LP LH/DIMMER [HI]) from the engine room relay block.

    2. Disconnect the 4B instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 2 - 4B-53 Always Below 1 Ω
      Relay terminal 2 or 4B-53 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY for LHD: REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here
    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY for RHD: REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. CHECK HEADLIGHT RELAY (H-LP RH)


    1. Remove the headlight relay (H-LP RH) from the No. 2 engine room relay block.

    2. Inspect the headlight light relay (H-LP RH).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT RELAY (H-LP RH RELAY)

    OK

  8. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [H-LP RH] - BATTERY)


    1. B008HTWC11
      *a

      Front view of wire harness connector

      (to Headlight Relay [H-LP RH])

      Remove the headlight relay (H-LP RH) from the No. 2 engine room relay block.

    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 Always 11 to 14 V
      Relay terminal 5 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY [H-LP RH RELAY] - HEADLIGHT LIGHT CONTROL ECU ASSEMBLY RH AND MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU])


    1. Remove the headlight relay (H-LP RH) from the No. 2 engine room relay block.

    2. Disconnect the A20 headlight light control ECU RH sub-assembly LH connector.

    3. Disconnect the I48 main body ECU (multiplex network body ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 3 - A20-13 (ECUB) Always Below 1 Ω
      Relay terminal 2 - I48-1 (DIM) Always Below 1 Ω
      Relay terminal 3 or A20-13 (ECUB) - Body ground Always 10 kΩ or higher
      Relay terminal 2 or I48-1 (DIM) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here
    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for RHD: REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR