LIGHTING SYSTEM Power Source Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives IG signals and supplies power to the No. 1 headlight ECU sub-assemblies via the H-LP relays.

WIRING DIAGRAM

B003XSFE04

CAUTION / NOTICE / HINT

Note


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

  • Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

PROCEDURE


  1. INSPECT NO. 1 HEADLIGHT ECU SUB-ASSEMBLY (ECUB TERMINAL VOLTAGE)

    B003YIRC31
    *1 No. 1 Headlight ECU Sub-assembly LH
    *2 No. 1 Headlight ECU Sub-assembly RH
    *a

    Component without harness connected

    (No. 1 Headlight ECU Sub-assembly)

    1. Disconnect the W1 No. 1 headlight ECU sub-assembly LH connector.

    2. Disconnect the G1 No. 1 headlight ECU sub-assembly RH connector.

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

      Standard Voltage
      No. 1 Headlight ECU Sub-assembly LH
      Tester Connection Condition Specified Condition
      W1-13 (ECUB) - Body ground Power switch on (IG) or light control switch in tail or head position 11 to 14 V
      No. 1 Headlight ECU Sub-assembly RH
      Tester Connection Condition Specified Condition
      G1-13 (ECUB) - Body ground Power switch on (IG) or light control switch in tail or head position 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (No. 1 Headlight ECU Sub-assembly LH) B
      NG (No. 1 Headlight ECU Sub-assembly RH) C

    B

    INSPECT H-LP LH RELAY Click here

    C

    INSPECT H-LP RH RELAY Click here

    A

  2. INSPECT NO. 1 HEADLIGHT ECU SUB-ASSEMBLY (IG TERMINAL VOLTAGE)

    B003YIRC32
    *1 No. 1 Headlight ECU Sub-assembly LH
    *2 No. 1 Headlight ECU Sub-assembly RH
    *a

    Component without harness connected

    (No. 1 Headlight ECU Sub-assembly)

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

      Standard Voltage
      No. 1 Headlight ECU Sub-assembly LH
      Tester Connection Condition Specified Condition
      W1-4 (IG) - Body ground Power switch on (IG) 11 to 14 V
      No. 1 Headlight ECU Sub-assembly RH
      Tester Connection Condition Specified Condition
      G1-4 (IG) - Body ground Power switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (NO. 1 HEADLIGHT ECU SUB-ASSEMBLY - BODY GROUND)


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

      Standard Resistance
      No. 1 Headlight ECU Sub-assembly LH
      Tester Connection Condition Specified Condition
      W1-12 (GND) - Body ground Always Below 1 Ω
      No. 1 Headlight ECU Sub-assembly RH
      Tester Connection Condition Specified Condition
      G1-12 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  4. INSPECT H-LP LH RELAY


    1. Inspect the H-LP LH relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE H-LP LH RELAY

    OK

  5. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - NO. 1 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
      3 (H-LP LH Relay) - W1-13 (ECUB) Always Below 1 Ω
      3 (H-LP LH Relay) or W1-13 (ECUB) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (POWER SOURCE - 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 Power switch off 11 to 14 V
      5 (H-LP LH Relay) - Body ground Power switch off 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (H-LP LH RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))


    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

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    B003Y2XC18
    *a

    Component without harness connected

    (Instrument Panel Junction Block Assembly)

    		 - -

    1. Remove the instrument panel junction block assembly.

      Click here

    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.

      Standard Resistance
      Tester Connection Condition Specified Condition
      4C-29 - MB-15 (HRLY) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

  9. INSPECT H-LP RH RELAY


    1. Inspect the H-LP RH relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE H-LP RH RELAY

    OK

  10. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - NO. 1 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
      3 (H-LP RH Relay) - G1-13 (ECUB) Always Below 1 Ω
      3 (H-LP RH Relay) or G1-13 (ECUB) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  11. CHECK HARNESS AND CONNECTOR (POWER SOURCE - 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 Power switch off 11 to 14 V
      5 (H-LP RH Relay) - Body ground Power switch off 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. CHECK HARNESS AND CONNECTOR (H-LP RH RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))


    1. Disconnect the K2 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) - K2-1 (DIM) Always Below 1 Ω
      2 (H-LP RH Relay) or K2-1 (DIM) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR