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 stored when a malfunction is detected in the seat belt buckle switch LH circuit.

DTC Code Detection Condition Trouble Area
B1656/38

One of the following conditions is met:


  • The center 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.

  • A center airbag sensor assembly malfunction.

  • No. 2 floor wire

  • Front seat inner belt assembly LH

  • Center airbag sensor assembly

WIRING DIAGRAM

A000T3WE57
*a Front Seat Inner Belt Assembly LH
*b Center 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.

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

      OK
      The connectors are properly connected.

    NG

    CONNECT CONNECTORS PROPERLY

    OK

  2. CHECK CONNECTORS


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

    2. A000N00E03
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Center Airbag Sensor Assembly
      *3 No. 2 Floor Wire

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

      OK
      The connectors are not deformed or damaged.

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  3. CHECK NO. 2 FLOOR WIRE


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

      A000MZ7E04
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH *2 Center 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 Center 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
      Tester Connection Switch Condition Specified Condition
      U4-1 (LBE+) - Body ground Power switch on (IG) Below 1 V
      U4-3 (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 15 (LBE+) and 23 (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
      Tester Connection Condition Specified Condition
      U4-1 (LBE+) - U4-3 (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
      Tester Connection Condition Specified Condition
      U4-1 (LBE+) - U4-3 (LBE-) Always 1 MΩ or higher
      U4-1 (LBE+) - Body ground Always 1 MΩ or higher
      U4-3 (LBE-) - Body ground Always 1 MΩ or higher

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  4. CHECK FRONT SEAT INNER BELT ASSEMBLY LH


    1. A000PQOE03
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Center Airbag Sensor Assembly

      Connect the connector to the center 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.

    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.


    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

  5. CHECK 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.


    NEXT

  6. CHECK CENTER AIRBAG SENSOR ASSEMBLY


    1. A000PQOE03
      Text in Illustration
      *1 Front Seat Inner Belt Assembly LH
      *2 Center 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.

    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.


    OK

    END (FRONT SEAT INNER BELT ASSEMBLY LH WAS DEFECTIVE)

    NG

    REPLACE CENTER AIRBAG SENSOR ASSEMBLY Click here