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

A003Y4UE30

INSPECTION PROCEDURE

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 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 SST, connect terminals 11 (LBE+) and 12 (LBE-) of connector B.

      A003XXGE19

      Note

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

      SST
      09843-18040

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P3-2 (LBE+) - P3-1 (LBE-) Always Below 1 Ω
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH *2 Airbag Sensor Assembly
      *3 Floor Wire *4 Connector B
      *5 Connector C - -
      *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)


    1. A003ZAYE02
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 Floor Wire
      *4 Connector C
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

      Disconnect SST from connector B.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P3-2 (LBE+) - P3-1 (LBE-) Always 1 MΩ or higher

    NG

    REPLACE FLOOR WIRE

    OK

  4. CHECK FLOOR WIRE (SHORT TO B+)


    1. A003ZAYE02
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 Floor Wire
      *4 Connector C
      *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 Switch Condition Specified Condition
      P3-2 (LBE+) - Body ground Power switch on (IG) Below 1 V
      P3-1 (LBE-) - Body ground Power switch on (IG) Below 1 V

    NG

    REPLACE FLOOR WIRE

    OK

  5. CHECK FLOOR WIRE (SHORT TO GROUND)


    1. A003ZAYE02
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 Floor Wire
      *4 Connector C
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P3-2 (LBE+) - Body ground Always 1 MΩ or higher
      P3-1 (LBE-) - Body ground Always 1 MΩ or higher

    NG

    REPLACE FLOOR WIRE

    OK

  6. CHECK FRONT SEAT INNER BELT ASSEMBLY LH


    1. A003ZKOE08
      Text in Illustration
      *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. Turn the power switch on (IG), and wait for at least 60 seconds.

    4. Clear the DTCs stored in memory Click here.

    5. Turn the power switch off.

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

    7. 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.


    NG

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here

    OK

    USE SIMULATION METHOD TO CHECK Click here

  7. REPLACE FRONT SEAT INNER BELT ASSEMBLY LH


    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. 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.


    NEXT

  8. CHECK AIRBAG SENSOR ASSEMBLY


    1. A003ZKOE08
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly

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

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

    3. Clear the DTCs stored in memory Click here.

    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.

      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.


    NG

    REPLACE AIRBAG SENSOR ASSEMBLY Click here

    OK

    END