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. Detection Item DTC Detection Condition Trouble Area
B1656/38 Seat Belt Buckle Switch LH Circuit Malfunction

    One of the following conditions is met:

  • The airbag sensor assembly detects a line short circuit signal, open circuit signal, short circuit to ground signal or short circuit to B+ signal in the seat belt buckle switch LH circuit for 2 seconds.

  • A front seat inner belt assembly LH malfunction.

  • An airbag sensor assembly malfunction.

  • No. 2 floor wire

  • Front seat inner belt assembly LH

  • Airbag sensor assembly

WIRING DIAGRAM

A01MGAOE40
for LHD
*a Front Seat Inner Belt Assembly LH
*b Airbag Sensor Assembly
A01MGAOE41
for RHD
*a 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

  • When disconnecting the cable from the negative (-) auxiliary battery terminal while performing repairs, some systems need to be initialized after the cable is reconnected.

    Click here

  • After replacing the airbag sensor assembly, refer to initialization.

    Click here

PROCEDURE


  1. CHECK CONNECTION OF CONNECTORS


    1. Turn the power switch off.

    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.

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

      Result
      Result Proceed to
      Connectors are properly connected A
      Connectors are not properly connected B

    B

    CONNECT CONNECTORS PROPERLY

    A

  2. CHECK CONNECTORS


    1. A01MJNXC08
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire

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

    2. Check that the connectors (on the airbag sensor assembly side and front seat inner belt assembly LH side) are not damaged.

      Result
      Result Proceed to
      Connectors are not deformed or damaged A
      Connectors are deformed or damaged B

    B

    REPLACE NO. 2 FLOOR WIRE

    A

  3. CHECK NO. 2 FLOOR WIRE


    1. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.

      A01MIXXC02
      *A for LHD - -
      *1 Front Seat Inner Belt Assembly LH *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire *4 Connector C
      *5 Connector B *6 Service Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

      		 *b

      Rear view of wire harness connector

      (to Airbag Sensor Assembly)
      A01MFR7C01
      *A for RHD - -
      *1 Front Seat Inner Belt Assembly LH *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire *4 Connector C
      *5 Connector B *6 Service Wire
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt Assembly LH)

      		 *b

      Rear view of wire harness connector

      (to Airbag Sensor Assembly)

    2. Turn the power switch on (IG).

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

      Standard Voltage
      for LHD:
      Tester Connection Switch Condition Specified Condition
      P43-2 (LBE+) - Body ground Power switch on (IG) Below 1 V
      P43-1 (LBE-) - Body ground Power switch on (IG) Below 1 V
      for RHD:
      Tester Connection Switch Condition Specified Condition
      P20-5 (LBE+) - Body ground Power switch on (IG) Below 1 V
      P20-4 (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, and wait for at least 90 seconds.

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

      Note

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

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

      Standard Resistance
      for LHD:
      Tester Connection Condition Specified Condition
      P43-2 (LBE+) - P43-1 (LBE-) Always Below 1 Ω
      for RHD:
      Tester Connection Condition Specified Condition
      P20-5 (LBE+) - P20-4 (LBE-) Always Below 1 Ω

    8. Disconnect the service wire from connector B.

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

      Standard Resistance
      for LHD:
      Tester Connection Condition Specified Condition
      P43-2 (LBE+) - P43-1 (LBE-) Always 1 MΩ or higher
      P43-2 (LBE+) - Body ground Always 1 MΩ or higher
      P43-1 (LBE-) - Body ground Always 1 MΩ or higher
      for RHD:
      Tester Connection Condition Specified Condition
      P20-5 (LBE+) - P20-4 (LBE-) Always 1 MΩ or higher
      P20-5 (LBE+) - Body ground Always 1 MΩ or higher
      P20-4 (LBE-) - Body ground Always 1 MΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  4. CHECK DTC


    1. A01MIH8C09
      *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, and wait for at least 2 seconds.

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

    4. Clear the DTCs.

      Click here


      Body Electrical > SRS Airbag > Clear DTCs

    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


      Body Electrical > SRS Airbag > Trouble Codes
      Result
      Result Proceed to
      DTC B1656/38 is not output A
      DTC B1656/38 is output B

      Tech Tips

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


    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  5. REPLACE FRONT SEAT INNER BELT ASSEMBLY LH


    1. Turn the power switch off.

    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 90 seconds.

    3. Replace the front seat inner belt assembly LH.

      Click here

      Tech Tips

      Perform the inspection using parts from a normal vehicle if possible.

      Result
      Proceed to
      NEXT

    NEXT

  6. CHECK DTC


    1. A01MIH8C09
      *1 Front Seat Inner Belt Assembly LH
      *2 Airbag Sensor Assembly

      Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.

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

    3. Clear the DTCs.

      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
      Result
      Result Proceed to
      DTC B1656/38 is not output A
      DTC B1656/38 is output B

      Tech Tips

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


    A

    END (FRONT SEAT INNER BELT ASSEMBLY LH WAS DEFECTIVE)

    B

    REPLACE AIRBAG SENSOR ASSEMBLY Click here