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 seat belt buckle switch LH (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. Detection Item DTC Detection Condition Trouble Area Test Mode / Check Mode
B1656/38 Seat Belt Buckle Switch LH Circuit Malfunction

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

  • Seat belt buckle switch LH malfunction

  • Airbag sensor assembly malfunction

  • No. 2 Floor wire

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

  • Airbag sensor assembly

 Does not apply to test/check mode

WIRING DIAGRAM

A0021EBE10
*a Seat Belt Buckle Switch LH (Front Seat Inner Belt Assembly LH)
*b Airbag Sensor Assembly

CAUTION / NOTICE / HINT

Note

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

Click here

PROCEDURE


  1. CHECK CONNECTORS


    1. Turn the power switch off.

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

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary 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 properly connected, 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.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  2. CHECK NO. 2 FLOOR WIRE (OPEN)


    1. A0020UGC01
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 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)

      Using a service wire, connect terminals 15 (LBE+) and 23 (LBE-) of connector B.

      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
      Q13-2 (LBE+) - Q13-1 (LBE-) Always Below 1 Ω

    3. Disconnect the service wire from connector B.

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  3. CHECK NO. 2 FLOOR WIRE (SHORT)


    1. A0022CZC01
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Q13-2 (LBE+) - Q13-1 (LBE-) Always 1 MΩ or higher
      Result
      Result
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  4. CHECK NO. 2 FLOOR WIRE (SHORT TO B+)


    1. A0022CZC01
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

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

    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
      Q13-2 (LBE+) - Body ground Power switch on (IG) Below 1 V
      Q13-1 (LBE-) - Body ground Power switch on (IG) Below 1 V

    4. Turn the power switch off.

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

      CAUTION:

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

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  5. CHECK NO. 2 FLOOR WIRE (SHORT TO GROUND)


    1. A0022CZC01
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Q13-2 (LBE+) - Body ground Always 1 MΩ or higher
      Q13-1 (LBE-) - Body ground Always 1 MΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  6. CHECK DTC


    1. A0020P8C02
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly

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

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

    3. Clear the DTCs stored in memory.

      Click here


      Body Electrical > SRS Airbag > Clear DTCs

    4. Turn the power switch off.

    5. Turn the power switch on (IG), and wait for at least 60 seconds.

    6. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      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.

      Result
      Result
      OK
      NG

    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  7. CHECK FRONT SEAT INNER BELT ASSEMBLY LH


    1. A0020P8C02
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly

      Turn the power switch off.

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

      CAUTION:

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

    3. Replace the front seat inner belt assembly LH with a known good one.

      Click here

      Tech Tips

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

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

    5. Clear the DTCs stored in memory.

      Click here


      Body Electrical > SRS Airbag > Clear DTCs

    6. Turn the power switch off.

    7. Turn the power switch on (IG), and wait for at least 60 seconds.

    8. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      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.

    9. Turn the power switch off.

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

      CAUTION:

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

    11. Restore the front seat inner belt assembly LH that was installed for testing to its original location.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here

    NG

    REPLACE AIRBAG SENSOR ASSEMBLY Click here