AIRBAG SYSTEM, Diagnostic DTC:B1825, B1826, B1827, B1828

DTC Code DTC Name
B1825 Short in Side Squib (LH) Circuit
B1826 Open in Side Squib (LH) Circuit
B1827 Short in Side Squib (LH) Circuit (to Ground)
B1828 Short in Side Squib (LH) Circuit (to +B)

DESCRIPTION

The front side squib LH circuit consists of the airbag ECU assembly and front seat airbag assembly LH.

The airbag ECU assembly uses this circuit to deploy the airbag when deployment conditions are met.

These DTCs are stored when a malfunction is detected in the front side squib LH circuit.

DTC No. DTC Detection Condition Trouble Area
B1825

  • The airbag ECU assembly receives a line short circuit signal in the front side squib LH circuit during primary check.

  • Front side squib LH malfunction

  • Airbag ECU assembly malfunction

  • Floor wire

  • Front seat assembly LH (Front seat wire LH)

  • Front seat airbag assembly LH (Front side squib LH)

  • Airbag ECU assembly
B1826

  • The airbag ECU assembly receives an open circuit signal in the front side squib LH circuit.

  • Front side squib LH malfunction

  • Airbag ECU assembly malfunction
B1827

  • The airbag ECU assembly receives a short circuit to ground signal in the front side squib LH circuit.

  • Front side squib LH malfunction

  • Airbag ECU assembly malfunction
B1828

  • The airbag ECU assembly receives a short circuit to B+ signal in the front side squib LH circuit.

  • Front side squib LH malfunction

  • Airbag ECU assembly malfunction

WIRING DIAGRAM

A004K0ZE02
*a Hb1
*b Front Seat Airbag Assembly LH (Front Side Squib LH)
*c 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.

Tech Tips


  • Perform the simulation method by selecting check mode (Signal Check) using the GTS Click here.

  • After selecting check mode (Signal Check), perform the simulation method by wiggling each connector of the airbag system or driving the vehicle on a city road or rough road Click here.

PROCEDURE


  1. CHECK CONNECTORS


    1. A004JJLE01
      Text in Illustration
      *1 Front Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Front Seat Wire LH
      *4 Floor Wire

      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 front seat airbag assembly LH and airbag ECU assembly. Also check that the connectors that link the floor wire and front seat wire LH are properly connected.

      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 front seat airbag assembly LH and airbag ECU assembly. Also disconnect the floor wire from the front seat wire LH.

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

      OK
      The terminals are not deformed or damaged.

    6. Check that the front seat wire LH connector (on the front seat airbag assembly LH side) is not damaged.

      OK
      The lock button is not disengaged, or the claw of the lock is not deformed or damaged.

    7. Check that the short springs for the floor wire and the front seat wire LH with the activation prevention mechanism are not deformed or damaged.

      OK
      The short springs are not deformed or damaged.

    NG

    REPLACE WIRE HARNESS

    OK

  2. CHECK FRONT SEAT AIRBAG ASSEMBLY LH (FRONT SIDE SQUIB LH)


    1. A004J26E02
      Text in Illustration
      *1 Front Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *a

      Front view of wire harness connector

      (to Front Seat Airbag Assembly LH)

      Connect the floor wire to the front seat wire LH and airbag ECU assembly.

    2. Connect SST (resistance 2.1 Ω) to connector E.

      CAUTION:

      Never connect the tester to the front seat airbag assembly LH (front side squib LH) for measurement, as this may lead to a serious injury due to airbag deployment.

      Note


      • Do not forcibly insert SST into the terminals of the connector when connecting it.

      • Insert SST straight into the terminals of the connector.

      SST
      09843-18061

    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.

      OK
      DTC B1825, B1826, B1827 or B1828 is not output.

      Tech Tips

      Codes other than DTCs B1825, B1826, B1827 and B1828 may be output at this time, but they are not related to this check.

    8. Turn the ignition switch off.

    9. 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.

    10. Disconnect SST from connector E.


    OK

    REPLACE FRONT SEAT AIRBAG ASSEMBLY LH Click here

    NG

  3. CHECK FLOOR WIRE


    1. A004ILGE02
      Text in Illustration
      *1 Front Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *a

      Front view of wire harness connector

      (to Front Seat Airbag Assembly LH)

      Disconnect the floor wire from the airbag ECU assembly.

    2. Check for a short to B+ in the circuit.


      1. 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
        b1-1 (SFL-) - Body ground Ignition switch ON Below 1 V
        b1-2 (SFL+) - 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.

    3. Check for an open in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        b1-1 (SFL-) - b1-2 (SFL+) Always Below 1 Ω

    4. Check for a short to ground in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        b1-1 (SFL-) - Body ground Always 1 MΩ or higher
        b1-2 (SFL+) - Body ground Always 1 MΩ or higher

    5. Check for a short in the circuit.


      1. Release the activation prevention mechanism built into connector B Click here.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        b1-1 (SFL-) - b1-2 (SFL+) Always 1 MΩ or higher

      3. Restore the released activation prevention mechanism of connector B to the original condition.


    NG

    CHECK FLOOR WIRE Click here

    OK

  4. CHECK DTC


    1. A004HY2E02
      Text in Illustration
      *1 Front Seat Airbag Assembly LH
      *2 Airbag ECU Assembly

      Connect the connectors to the front seat airbag assembly LH and airbag ECU assembly.

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

    3. Clear the DTCs stored in memory Click here.

    4. Turn the ignition switch off.

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

    6. Check for DTCs Click here.

      OK
      DTC B1825, B1826, B1827 or B1828 is not output.

      Tech Tips

      Codes other than DTCs B1825, B1826, B1827 and B1828 may be output at this time, but they are not related to this check.


    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

    REPLACE AIRBAG ECU ASSEMBLY Click here

  5. CHECK FLOOR WIRE


    1. A004IFAE02
      Text in Illustration
      *1 Front Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Front Seat Wire LH
      *4 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Wire LH)

      Disconnect the front seat wire LH from the floor wire.

    2. Check for a short to B+ in the circuit.


      1. 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
        Hb1-1 - Body ground Ignition switch ON Below 1 V
        Hb1-2 - 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.

    3. Check for an open in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Hb1-1 - Hb1-2 Always Below 1 Ω

    4. Check for a short to ground in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Hb1-1 - Body ground Always 1 MΩ or higher
        Hb1-2 - Body ground Always 1 MΩ or higher

    5. Check for a short in the circuit.


      1. Release the activation prevention mechanism built into connector B Click here.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Hb1-1 - Hb1-2 Always 1 MΩ or higher

      3. Restore the released activation prevention mechanism of connector B to the original condition.


    NG

    REPLACE FLOOR WIRE

    OK

  6. CHECK FRONT SEAT WIRE LH


    1. A004JOME02
      Text in Illustration
      *1 Front Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Front Seat Wire LH
      *4 Floor Wire
      *a

      Front view of wire harness connector

      (to Front Seat Airbag Assembly LH)

      Check for a short to B+ in the circuit.


      1. 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
        b1-1 (SFL-) - Body ground Ignition switch ON Below 1 V
        b1-2 (SFL+) - 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.

    2. Check for an open in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        b1-1 (SFL-) - b1-2 (SFL+) Always Below 1 Ω

    3. Check for a short to ground in the circuit.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        b1-1 (SFL-) - Body ground Always 1 MΩ or higher
        b1-2 (SFL+) - Body ground Always 1 MΩ or higher

    4. Check for a short in the circuit.


      1. Release the activation prevention mechanism built into connector D Click here.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        b1-1 (SFL-) - b1-2 (SFL+) Always 1 MΩ or higher

      3. Restore the released activation prevention mechanism of connector D to the original condition.


    OK

    USE SIMULATION METHOD TO CHECK Click here

    NG

    REPLACE FRONT SEAT ASSEMBLY LH