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AIRBAG SYSTEM, Diagnostic DTC:B1656/38

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DTC Code DTC Name
B1656/38 Seat Belt Buckle Switch LH Circuit Malfunction
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DESCRIPTION

The seat belt buckle switch LH circuit consists of the center airbag sensor assembly and the front seat inner belt LH.

DTC B1656/38 is recorded 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 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 for 2 seconds.

  • Front seat inner belt 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
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WIRING DIAGRAM

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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 (see pageClick 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 (see pageClick here).

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PROCEDURE


  1. Click here

    CHECK FOR DTC


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

    2. Clear the DTCs (see pageClick here).

    3. Turn the power switch OFF.

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

    5. Check for DTCs (see pageClick here).

      OK
      DTC B1656 is not output.
      Tip:

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


  2. Click here

    CHECK CONNECTION OF CONNECTORS


    1. Turn the power switch OFF.

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

      OK
      The connectors are properly connected.

  3. Click here

    CHECK CONNECTORS


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

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

      OK
      The connectors are not deformed or damaged.

  4. Click here

    CHECK NO. 2 FLOOR WIRE (CENTER AIRBAG SENSOR ASSEMBLY - FRONT SEAT INNER BELT LH)


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

    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
      S17-1 (LBE+) - Body ground Power switch ON (IG) Below 1 V
      S17-3 (LBE-) - Body ground Power switch ON (IG) Below 1 V

    4. Turn the power switch OFF.

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

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

      Standard resistance
      Tester Connection Condition Specified Condition
      S17-1 (LBE+) - S8-10 (LBE+) Always Below 1 Ω

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

      Standard resistance
      Tester Connection Condition Specified Condition
      S17-1 (LBE+) - Body ground Always 1 MΩ or higher
      S17-3 (LBE-) - Body ground Always Below 1 Ω

  5. Click here

    CHECK FRONT SEAT INNER BELT LH


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

    2. Connect the negative (-) terminal cable to the auxiliary battery, 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 (see pageClick 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 (see pageClick here).

      OK
      DTC B1656 is not output.
      Tip:

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


  6. Click here

    REPLACE FRONT SEAT INNER BELT LH


    1. Turn the power switch OFF.

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

    3. Replace the front seat inner belt LH (see pageClick here).

      Tip:

      Perform the inspection using parts from a normally functioning vehicle if possible.


  7. Click here

    CHECK CENTER AIRBAG SENSOR ASSEMBLY


    1. Connect the negative (-) terminal cable to the auxiliary battery, 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 (see pageClick 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 (see pageClick here).

      OK
      DTC B1656 is not output.
      Tip:

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


  8. Click here

    USE SIMULATION METHOD TO CHECKClick here

  9. Click here

    CONNECT CONNECTORS PROPERLY

  10. Click here

    REPLACE NO. 2 FLOOR WIRE

  11. Click here

    REPLACE NO. 2 FLOOR WIRE

  12. Click here

    USE SIMULATION METHOD TO CHECKClick here

  13. Click here

    REPLACE CENTER AIRBAG SENSOR ASSEMBLYClick here

  14. Click here

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LHClick here