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 center airbag sensor assembly and front seat inner belt assembly LH.

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

DTC No. DTC Detection Condition Trouble Area
B1656/38

  • The center 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

  • Center airbag sensor assembly malfunction

  • No. 2 floor wire

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

  • Center airbag sensor assembly

WIRING DIAGRAM

A01NGVZE04

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK CONNECTORS


    1. Turn the power switch off.

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

      Note

      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 center 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 center airbag sensor assembly and front seat inner belt assembly LH.

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

      OK
      The terminals are not deformed or damaged.

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  2. CHECK NO. 2 FLOOR WIRE (OPEN)


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

      A01NFFRE02

      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
      P7-1 (LBE+) - P7-3 (LBE-) Always Below 1 Ω
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH (Seat Belt Buckle Switch LH) *2 Center Airbag Sensor Assembly
      *3 No. 2 Floor Wire *4

      Front view of wire harness connector

      (to Center Airbag Sensor Assembly)
      *5

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

      		 *6 Connector B
      *7 Connector C - -

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  3. CHECK NO. 2 FLOOR WIRE (SHORT)


    1. A01NETWE02
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH (Seat Belt Buckle Switch LH)
      *2 Center Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *4

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)
      *5 Connector C

      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
      P7-1 (LBE+) - P7-3 (LBE-) Always 1 MΩ or higher

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

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


    1. A01NETWE02
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH (Seat Belt Buckle Switch LH)
      *2 Center Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *4

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)
      *5 Connector C

      Connect the cable to the negative (-) 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
      P7-1 (LBE+) - Body ground Power switch on (IG) Below 1 V
      P7-3 (LBE-) - Body ground Power switch on (IG) Below 1 V

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

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


    1. A01NETWE02
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH (Seat Belt Buckle Switch LH)
      *2 Center Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *4

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)
      *5 Connector C

      Turn the power switch off.

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

      Note

      Wait at least 90 seconds after disconnecting the cable from the negative (-) 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
      P7-1 (LBE+) - Body ground Always 1 MΩ or higher
      P7-3 (LBE-) - Body ground Always 1 MΩ or higher

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  6. CHECK FRONT SEAT INNER BELT ASSEMBLY LH


    1. A01NEJLE01
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH (Seat Belt Buckle Switch LH)
      *2 Center Airbag Sensor Assembly

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

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

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

    4. Clear the DTCs stored in the 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 (-) battery terminal.

      Note

      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 part Click here.

      Tech Tips

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


    NEXT

  8. CHECK CENTER AIRBAG SENSOR ASSEMBLY


    1. A01NEJLE01
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH (Seat Belt Buckle Switch LH)
      *2 Center Airbag Sensor Assembly

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

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

    3. Clear the DTCs stored in the 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 CENTER AIRBAG SENSOR ASSEMBLY Click here

    OK

    END