AIRBAG SYSTEM, Diagnostic DTC:B1678, B1679

DTC Code DTC Name
B1678 Lost Communication with Rear Floor Airbag Sensor LH
B1679 Rear Floor Airbag Sensor LH Initialization Incomplete

DESCRIPTION


DTC Code DTC Detection Condition Trouble Area

B1678

B1679

  • The airbag ECU 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 No. 2 airbag sensor assembly circuit.

  • No. 2 airbag sensor assembly malfunction.

  • Airbag ECU assembly malfunction.

  • Floor wire

  • No. 2 airbag sensor assembly

  • Airbag ECU assembly

WIRING DIAGRAM

A004KU0E02
*a No. 2 Airbag Sensor Assembly
*b Airbag ECU Assembly

CAUTION / NOTICE / HINT

Note

After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work Click here.

PROCEDURE


  1. CHECK CONNECTORS


    1. Turn the ignition switch off.

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

      CAUTION:

      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 airbag ECU assembly and No. 2 airbag sensor assembly.

      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 ECU assembly and No. 2 airbag sensor assembly.

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

      OK
      The connectors are not deformed or damaged.

    NG

    REPLACE FLOOR WIRE

    OK

  2. CHECK FLOOR WIRE (OPEN)


    1. A004K3DE04
      Text in Illustration
      *1 No. 2 Airbag Sensor Assembly
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *4 Service Wire
      *a

      Front view of wire harness connector

      (to Airbag ECU Assembly)
      *b

      Front view of wire harness connector

      (to No. 2 Airbag Sensor Assembly)

      Using a service wire, connect terminals 11 (BBL2+) and 12 (BBL2-) of connector B.

      Note

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H16-1 (BBL2-) - H16-2 (BBL2+) Always Below 1 Ω

    3. Disconnect the service wire from connector B.


    NG

    REPLACE FLOOR WIRE

    OK

  3. CHECK FLOOR WIRE (SHORT)


    1. A004JDKE02
      Text in Illustration
      *1 No. 2 Airbag Sensor Assembly
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *a

      Front view of wire harness connector

      (to No. 2 Airbag Sensor Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H16-1 (BBL2-) - H16-2 (BBL2+) Always 1 MΩ or higher

    NG

    REPLACE FLOOR WIRE

    OK

  4. CHECK FLOOR WIRE (SHORT TO B+)


    1. A004JDKE02
      Text in Illustration
      *1 No. 2 Airbag Sensor Assembly
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *a

      Front view of wire harness connector

      (to No. 2 Airbag Sensor Assembly)

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

    2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H16-1 (BBL2-) - Body ground Ignition switch ON Below 1 V
      H16-2 (BBL2+) - Body ground Ignition switch ON Below 1 V

    4. Turn the ignition switch off.

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

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.


    NG

    REPLACE FLOOR WIRE

    OK

  5. CHECK FLOOR WIRE (SHORT TO GROUND)


    1. A004JDKE02
      Text in Illustration
      *1 No. 2 Airbag Sensor Assembly
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *a

      Front view of wire harness connector

      (to No. 2 Airbag Sensor Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H16-1 (BBL2-) - Body ground Always 1 MΩ or higher
      H16-2 (BBL2+) - Body ground Always 1 MΩ or higher

    NG

    REPLACE FLOOR WIRE

    OK

  6. CHECK NO. 2 AIRBAG SENSOR ASSEMBLY


    1. A004H7ME05
      Text in Illustration
      *1 No. 2 Airbag Sensor Assembly
      *2 Airbag ECU Assembly

      Connect the connectors to the No. 2 airbag sensor assembly and airbag ECU assembly.

    2. Replace the No. 2 airbag sensor assembly with a new one.

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

    4. Clear the DTCs stored in memory Click here.

    5. Turn the ignition switch off.

    6. Turn the ignition switch to ON, and wait for at least 60 seconds.

    7. Check for DTCs Click here.

      Result Proceed to
      DTCs B1678 and B1679 are not output. A
      DTC B1678 or B1679 is output. B

      Tech Tips

      Codes other than DTCs B1678 and B1679 may be output at this time, but they are not related to this check.


    A

    END (NO. 2 AIRBAG SENSOR ASSEMBLY WAS DEFECTIVE)

    B

    REPLACE AIRBAG ECU ASSEMBLY Click here