PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:B2075

DTC Code DTC Name
B2075 Passenger 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 passenger 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
B2075 A malfunction in the front seat inner belt (buckle switch) circuit.

  • Front seat inner belt assembly (for passenger side)

  • Harness or connector

  • Seat belt control ECU

WIRING DIAGRAM

A01XLDSE01

PROCEDURE


  1. CHECK FOR DTC


    1. Clear the DTCs Click here.

    2. Check for DTCs Click here.

      OK
      DTC B2075 is not output.

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  2. CHECK SEAT BELT CONTROL ECU


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

      A01XH32E01
      *1 Component with harness connected: (Seat Belt Control ECU)
      *2 Front seat belt fastened
      *3 Front seat belt unfastened

    2. Using an oscilloscope, check the waveform.

      Measurement Condition
      Item Content
      Tester Connection G118-5 (PBK+) - G118-6 (PBK-)
      Tool Setting 2 V/DIV., 20 ms/DIV.
      Condition Ignition switch ON, front seat belt (for passenger side) fastened → unfastened
      OK
      Waveform is as shown in illustration.

    OK

    REPLACE SEAT BELT CONTROL ECU Click here

    NG

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


    1. Disconnect the G118 ECU connector.

    2. Disconnect the Q21*1 or R34*2 belt connector.


      • *1: for LHD

      • *2: for RHD

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      G118-5 (PBK+) - Q21-5 (RBE+) Always Below 1 Ω
      G118-6 (PBK-) - Q21-4 (RBE-)
      G118-5 (PBK+) - Body ground Always 10 kΩ or higher
      G118-6 (PBK-) - Body ground
      for RHD
      Tester Connection Condition Specified Condition
      G118-5 (PBK+) - R34-5 (LBE+) Always Below 1 Ω
      G118-6 (PBK-) - R34-4 (LBE-)
      G118-5 (PBK+) - Body ground Always 10 kΩ or higher
      G118-6 (PBK-) - Body ground

    OK

    REPLACE FRONT SEAT INNER BELT ASSEMBLY (for Passenger Side) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR