PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:B2074

DTC Code DTC Name
B2074 Driver Side Seat Belt Buckle Switch Circuit Malfunction

DESCRIPTION

This DTC is stored when there is a malfunction in the front seat inner belt buckle switch circuit for the driver side. The seat belt control ECU receives buckle switch condition information from the front seat inner belt and controls the pre-crash safety system.

DTC Code DTC Detection Condition Trouble Area
B2074 A malfunction in the front seat inner belt (buckle switch) circuit.

  • Front seat inner belt assembly (for driver side)

  • Harness or connector

  • Seat belt control ECU

WIRING DIAGRAM

A006SODE01

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK SEAT BELT CONTROL ECU

    A006VHVE01
    Text in Illustration
    *1 for LHD
    *2 for RHD
    *3

    Component with harness connected

    (Seat Belt Control ECU)

    1. for LHD:

      Remove the seat belt control ECU, but do not disconnect the connector Click here.

    2. for RHD:

      Remove the seat belt control ECU, but do not disconnect the connector Click here.

    3. Using an oscilloscope, check the waveform.

      Measurement Condition
      Item Content
      Tester Connection

      • A53-5 (LBL+) - A53-6 (LBL-)*1

      • D110-4 (RBL+) - D110-3 (RBL-)*2
      Tool Setting 2 V/DIV., 20 ms/DIV.
      Condition Ignition switch ON, front seat belt fastened

      *1: for LHD

      *2: for RHD

      Result
      Result Proceed to
      NG A
      OK (for LHD) B
      OK (for RHD) C

    B

    REPLACE SEAT BELT CONTROL ECU Click here

    C

    REPLACE SEAT BELT CONTROL ECU Click here

    A

  2. CHECK HARNESS AND CONNECTOR (SEAT BELT CONTROL ECU - FRONT SEAT INNER BELT)

    *1: for LHD

    *2: for RHD


    1. A006ULOE02
      Text in Illustration
      *1 for LHD
      *2 for RHD
      *3

      Front view of wire harness connector

      (to Seat Belt Control ECU)
      *4

      Front view of wire harness connector

      (to Front Seat Inner Belt)

      Disconnect the A53*1 or D110*2 ECU connector.

    2. Disconnect the G48*1 or H5*2 belt connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A53-6 (LBL-) - G48-1 (LBL-) Always Below 1 Ω
      A53-5 (LBL+) - G48-2 (LBL+)
      A53-6 (LBL-) - Body ground Always 10 kΩ or higher
      A53-5 (LBL+) - Body ground
      for RHD
      Tester Connection Condition Specified Condition
      D110-3 (RBL-) - H5-1 (RBE-) Always Below 1 Ω
      D110-4 (RBL+) - H5-2 (RBE+)
      D110-3 (RBL-) - Body ground Always 10 kΩ or higher
      D110-4 (RBL+) - Body ground
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE FRONT SEAT INNER BELT ASSEMBLY RH Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here