LIGHTING SYSTEM Power Source Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives IG signals and supplies power to the headlight control computer assembly LH or RH via the LH LAMP relay or RH LAMP relay.

WIRING DIAGRAM

B002E16E04

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 Service Bulletin.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (HEADLIGHT CONTROL COMPUTER ASSEMBLY - POWER SOURCE AND BODY GROUND)


    1. Disconnect the A29 headlight control computer assembly LH connector.

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

      Standard Voltage
      Headlight Control Computer Assembly LH
      Tester Connection Switch Condition Specified Condition
      A29-13 (ECUB) - Body ground Engine Switch on (IG) or light control switch tail or head position 11 to 14 V
      A29-4 (IG) - Body ground Engine switch on (IG) 11 to 14 V
      Headlight Control Computer Assembly RH
      Tester Connection Switch Condition Specified Condition
      A30-13 (ECUB) - Body ground Engine Switch on (IG) or light control switch tail or head position 11 to 14 V
      A30-4 (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 Control Computer Assembly LH
      Tester Connection Condition Specified Condition
      A29-12 (GND) - Body ground Always Below 1 Ω
      Headlight Control Computer Assembly RH
      Tester Connection Condition Specified Condition
      A30-12 (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 RH LAMP RELAY Click here

    B

  2. INSPECT LH LAMP RELAY


    1. Inspect the LH LAMP relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE H-LP LH RELAY

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE - LH LAMP RELAY)


    1. B002D79C16
      *a

      Front view of wire harness connector

      (to LH LAMP RELAY)

      Remove the LH LAMP relay 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 (LH LAMP RELAY - HEADLIGHT CONTROL COMPUTER 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 - A29-13 (ECUB) Always Below 1 Ω
      Relay terminal 3 or A29-13 (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 (LH LAMP RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))


    1. Remove the main body ECU from the cowl side junction block LH.

      Click here

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

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

    OK

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

    NG

  6. CHECK HARNESS AND CONNECTOR (LH LAMP RELAY - COWL SIDE JUNCTION BLOCK LH)


    1. Remove the LH LAMP relay from the No. 2 engine room relay block.

    2. Disconnect the 5D cowl side junction block LH connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 2 - 5D-9 Always Below 1 Ω
      Relay terminal 2 or 5D-9 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COWL SIDE JUNCTION BLOCK LH Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. CHECK RH LAMP RELAY


    1. Remove the RH LAMP relay from the No. 2 engine room relay block.

    2. Inspect the RH LAMP relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT RELAY (H-LP RH RELAY)

    OK

  8. CHECK HARNESS AND CONNECTOR (RH LAMP RELAY - BATTERY)


    1. B002D79C11
      *a

      Front view of wire harness connector

      (to RH LAMP RELAY)

      Remove the RH LAMP relay 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 (RH LAMP RELAY - HEADLIGHT LIGHT CONTROL ECU ASSEMBLY RH)


    1. Remove the RH LAMP relay from the No. 2 engine room relay block.

    2. Disconnect the A30 headlight control computer assembly RH connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 3 - A30-13 (ECUB) Always Below 1 Ω
      Relay terminal 3 or A30-13 (ECUB) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (RH LAMP RELAY - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU])


    1. Remove the RH LAMP relay from the No. 2 engine room relay block.

    2. Remove the cowl side junction block LH.

      Click here

    3. Remove the main body ECU (multiplex network body ECU) from the cowl side junction block LH.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 2 - MB-22 (DIM) Always Below 1 Ω
      Relay terminal 2 or MB-22 (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

  11. CHECK HARNESS AND CONNECTOR (RH LAMP RELAY - COWL SIDE JUNCTION BLOCK LH)


    1. Remove the RH LAMP relay from the No. 1 engine room relay block.

    2. Disconnect the 5D cowl side junction block LH connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 2 - 5D-21 Always Below 1 Ω
      Relay terminal 2 or 5D-21 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COWL SIDE JUNCTION BLOCK LH Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR