PRE-CRASH SAFETY SYSTEM Power Source Circuit

DESCRIPTION

This circuit supplies power to the seat belt control ECU.

WIRING DIAGRAM

A0041HUE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (SEAT BELT CONTROL ECU - BODY GROUND)


    1. Disconnect the L3 seat belt control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L3-8 (PGND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK HARNESS AND CONNECTOR (IG1 CIRCUIT)


    1. A0043VYE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Seat Belt Control ECU)

      Disconnect the L4 seat belt control ECU connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      L4-8 (IG1) - L3-8 (PGND) Power switch on (IG) 11 to 14 V

    NG

    INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (IG1 NO. 1 RELAY) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (+B CIRCUIT)


    1. A0042HUE30
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Seat Belt Control ECU)

      Disconnect the L3 seat belt control ECU connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      L3-7 (+B) - Body ground Always 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (SEAT BELT CONTROL ECU - INSTRUMENT PANEL JUNCTION BLOCK) Click here

    OK

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

  4. CHECK HARNESS AND CONNECTOR (SEAT BELT CONTROL ECU - INSTRUMENT PANEL JUNCTION BLOCK)


    1. Disconnect the L3 seat belt control ECU connector.

    2. Disconnect the 2A instrument panel junction block connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L3-7 (+B) - 2A-5 Always Below 1 Ω
      L3-7 (+B) or 2A-5 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

  5. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (IG1 NO. 1 RELAY)


    1. Remove the instrument panel junction block assembly.

      A00404YE06
      Text in Illustration
      *A for LHD *B for RHD
      *a Instrument Panel Junction Block Assembly - -

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

      Standard Resistance (for LHD)
      Tester Connection Condition Specified Condition
      2E-1 - 2B-16 Always 10 kΩ or higher
      When auxiliary battery voltage applied to terminals 2B-25 and 2B-6 Below 1 Ω
      Standard Resistance (for RHD)
      Tester Connection Condition Specified Condition
      2F-1 - 2B-16 Always 10 kΩ or higher
      When auxiliary battery voltage applied to terminals 2B-25 and 2B-6 Below 1 Ω

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    OK

  6. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - SEAT BELT CONTROL ECU)


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

    2. Disconnect the L4 seat belt control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2B-16 - L4-8 (IG1) Always Below 1 Ω
      2B-16 or L4-8 (IG1) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND)


    1. Disconnect the 2B 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
      2B-6 - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - POWER MANAGEMENT CONTROL ECU)


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

    2. Disconnect the L6 power management control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2B-25 - L6-2 (IG1D) Always Below 1 Ω
      2B-25 or L6-2 (IG1D) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - AUXILIARY BATTERY)