AIRBAG SYSTEM, Diagnostic DTC:B1656/38

DTC Code DTC Name
B1656/38 Seat Belt Buckle Switch LH Circuit Malfunction

DESCRIPTION

The seat belt buckle switch LH circuit consists of the airbag sensor assembly and front seat inner belt assembly LH.

DTC B1656/38 is stored when a malfunction is detected in the seat belt buckle switch LH circuit.

DTC No. DTC Detection Condition Trouble Area
B1656/38

  • The airbag sensor assembly receives a line short circuit signal, an open circuit signal, a short circuit to ground signal or a short circuit to B+ signal in the seat belt buckle switch LH circuit.

  • Front seat inner belt assembly LH malfunction

  • Airbag sensor assembly malfunction

  • Floor wire

  • Front seat inner belt assembly LH (Seat belt buckle switch LH)

  • Airbag sensor assembly

WIRING DIAGRAM

A011RWUE04

INSPECTION PROCEDURE

Note

After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Click here.

PROCEDURE

  1. CHECK CONNECTORS

    1. Turn the ignition switch off.

    2. Disconnect the cable from the negative (-) battery terminal.

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

    3. Check that the connectors are properly connected to the airbag sensor assembly and front seat inner belt assembly LH.

      OK
      The connectors are properly connected.

      Tech Tips

      If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

    4. Disconnect the connectors from the airbag sensor assembly and front seat inner belt assembly LH.

    5. Check that the terminals of the connectors are not damaged.

      OK
      The terminals are not deformed or damaged.
    NG

    REPLACE FLOOR WIRE

    OK

  2. CHECK FLOOR WIRE (OPEN)

    1. Using a service wire, connect terminals 10 (LBE+) and 18 (LBE-) of connector B.

      A011S2ZE02

      Note

      Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N32-2 (LBE+) - N32-1 (LBE-) Always Below 1 Ω

    3. Disconnect the service wire from connector B.

      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 Floor Wire
      *4 Service Wire
      *a

      Front view of wire harness connector

      (to Airbag Sensor Assembly)
      *b

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)
    NG

    REPLACE FLOOR WIRE

    OK

  3. CHECK FLOOR WIRE (SHORT)

    A011R73E02

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N32-2 (LBE+) - N32-1 (LBE-) Always 1 MΩ or higher
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)
    NG

    REPLACE FLOOR WIRE

    OK

  4. CHECK FLOOR WIRE (SHORT TO B+)

    1. Connect the cable to the negative (-) battery terminal.

      A011R73E02

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      N32-2 (LBE+) - Body ground Ignition switch ON Below 1 V
      N32-1 (LBE-) - Body ground Ignition switch ON Below 1 V

    4. Turn the ignition switch off.

    5. Disconnect the cable from the negative (-) battery terminal.

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)
    NG

    REPLACE FLOOR WIRE

    OK

  5. CHECK FLOOR WIRE (SHORT TO GROUND)

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

      A011R73E02
      Standard Resistance
      Tester Connection Condition Specified Condition
      N32-2 (LBE+) - Body ground Always 1 MΩ or higher
      N32-1 (LBE-) - Body ground Always 1 MΩ or higher
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)
    NG

    REPLACE FLOOR WIRE

    OK

  6. CHECK DTC

    1. Connect the connectors to the airbag sensor assembly and front seat inner belt assembly LH.

      A011URDE01

    2. Connect the cable to the negative (-) battery terminal.

    3. Clear the DTCs stored in memory Click here.

    4. Turn the ignition switch off.

    5. Turn the ignition switch to ON, and wait for at least 60 seconds.

    6. Check for DTCs Click here.

      OK
      DTC B1656/38 is not output.

      Tech Tips

      Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.

      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
    NG

    CHECK FRONT SEAT INNER BELT ASSEMBLY LH Click here

    OK

    USE SIMULATION METHOD TO CHECK Click here

  7. CHECK FRONT SEAT INNER BELT ASSEMBLY LH

    1. Turn the ignition switch off.

      A011URDE01

    2. Disconnect the cable from the negative (-) battery terminal.

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

    3. Replace the front seat inner belt assembly LH with a known good one Click here for Manual Seat, Click here for Power Seat).

      Tech Tips

      Perform the following inspection using known good parts from another vehicle if possible.

    4. Connect the cable to the negative (-) battery terminal.

    5. Clear the DTCs stored in memory Click here.

    6. Turn the ignition switch off.

    7. Turn the ignition switch to ON, and wait for at least 60 seconds.

    8. Check for DTCs Click here.

      OK
      DTC B1656/38 is not output.
      Result
      Result Proceed to
      OK (for Manual Seat) A
      OK (for Power Seat) B
      NG C

      Tech Tips

      Codes other than DTC B1656/38 may be output at this time, but they are not related to this check.

    9. Turn the ignition switch off.

    10. Disconnect the cable from the negative (-) battery terminal.

    11. Restore the front seat inner belt assembly LH that was installed for testing to its original location Click here for Manual Seat, Click here for Power Seat).

      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
    B

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here

    C

    REPLACE AIRBAG SENSOR ASSEMBLY Click here

    A

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here