AIRBAG SYSTEM, Diagnostic DTC:B1825/56, B1826/56, B1827/56, B1828/56

DTC Code DTC Name
B1825/56 Short in Side Squib LH Circuit
B1826/56 Open in Side Squib LH Circuit
B1827/56 Short to GND in Side Squib LH Circuit
B1828/56 Short to B+ in Side Squib LH Circuit

DESCRIPTION

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

The circuit instructs the SRS to deploy when deployment conditions are met.

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

DTC No. Detection Item DTC Detection Condition Trouble Area
B1825/56 Short in Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects a line short circuit signal 5 times in the front side squib LH circuit during the primary check.

  • A front seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • No. 2 floor wire

  • Front seat airbag assembly LH

  • Airbag ECU assembly
B1826/56 Open in Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects an open circuit signal in the front side squib LH circuit for 2 seconds.

  • A front seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • No. 2 floor wire

  • Front seat airbag assembly LH

  • Airbag ECU assembly
B1827/56 Short to GND in Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects a short circuit to ground signal in the front side squib LH circuit for 0.5 seconds.

  • A front seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • No. 2 floor wire

  • Front seat airbag assembly LH

  • Airbag ECU assembly
B1828/56 Short to B+ in Side Squib LH Circuit

One of the following conditions is met:


  • The airbag ECU assembly detects a short circuit to B+ signal in the front side squib LH circuit for 0.5 seconds.

  • A front seat airbag assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • No. 2 floor wire

  • Front seat airbag assembly LH

  • Airbag ECU assembly

WIRING DIAGRAM

B00599AE92
*a Qd1
*b Front Seat Airbag Assembly LH
*c Airbag ECU Assembly

CAUTION / NOTICE / HINT

Note


  • After turning the engine 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

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

    Click here

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

    Click here

Tech Tips

To perform the simulation method, enter check mode (signal check) with the GTS (Click here ), and then wiggle each connector of the airbag system or drive the vehicle on various types of road Click here.

PROCEDURE


  1. CHECK FRONT SEAT AIRBAG ASSEMBLY LH


    1. B0058Z6C04
      *1 Front Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Connector C
      *4 SST
      *a

      Front view of wire harness connector

      (to Front Seat Airbag Assembly LH)

      Turn the engine switch off.

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

    3. Disconnect the connector from the front seat airbag assembly LH.

    4. Connect the red wire side of SST (resistance: 2.1 Ω) to connector C.

      CAUTION:

      Never connect the tester to the front seat airbag assembly 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 SST.

      • Insert SST straight into the terminals of the connector.

      SST
      09843-18061

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

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

    7. Clear the DTCs.

      Click here


      Body Electrical > SRS Airbag > Clear DTCs

    8. Turn the engine switch off.

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

    10. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      Result
      Proceed to
      DTC B1825/56, B1826/56, B1827/56 or B1828/56 is not output.
      DTC B1825/56, B1826/56, B1827/56 or B1828/56 is output.

      Tech Tips

      Codes other than DTC B1800/51, B1801/51, B1802/51 and B1803/51 may be output at this time, but they are not related to this check.

    11. Turn the engine switch off.

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

    13. Disconnect SST from connector C.


    DTC B1825/56, B1826/56, B1827/56 or B1828/56 is not output.

    REPLACE FRONT SEAT AIRBAG ASSEMBLY LH for Power Seat: Click here
    REPLACE FRONT SEAT AIRBAG ASSEMBLY LH for Manual Seat: Click here

    DTC B1825/56, B1826/56, B1827/56 or B1828/56 is output.

  2. CHECK CONNECTORS


    1. Disconnect the connectors from the airbag ECU assembly.

    2. B0059PTC04
      *1 Front Seat Airbag Assembly LH
      *2 No. 2 Floor Wire
      *3 Airbag ECU Assembly

      Check that the connectors (on the airbag ECU assembly side and front seat airbag assembly LH side) are not damaged.

      OK
      The lock button is not disengaged, and the claw of the lock is not deformed or damaged.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  3. CHECK NO. 2 FLOOR WIRE


    1. B0057XCC05
      *1 Front Seat Airbag Assembly LH
      *2 No. 2 Floor Wire
      *3 Airbag ECU Assembly
      *4 Connector C
      *a

      Front view of wire harness connector

      (to Front Seat Airbag Assembly LH)

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

    2. Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      Qd1-1 (SFL+) - Body ground Engine switch on (IG) Below 1 V
      Qd1-2 (SFL-) - Body ground Engine switch on (IG) Below 1 V

    4. Turn the engine switch off.

    5. Disconnect the cable from the negative (-) battery terminal, 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
      Qd1-1 (SFL+) - Qd1-2 (SFL-) Always Below 1 Ω

    7. Release the activation prevention mechanism built into connector B.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Qd1-1 (SFL+) - Qd1-2 (SFL-) Always 1 MΩ or higher

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Qd1-1 (SFL+) - Body ground Always 1 MΩ or higher
      Qd1-2 (SFL-) - Body ground Always 1 MΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  4. CHECK DTC


    1. B0059JZC12
      *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, and wait for at least 2 seconds.

    3. Turn the engine 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 engine switch off.

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

    7. Check for DTCs.

      Click here


      Body Electrical > SRS Airbag > Trouble Codes
      Result
      Proceed to
      DTC B1825/56, B1826/56, B1827/56 or B1828/56 is not output
      DTC B1825/56, B1826/56, B1827/56 or B1828/56 is output

      Tech Tips

      Codes other than DTC B1825/56, B1826/56, B1827/56 and B1828/56 may be output at this time, but they are not related to this check.


    DTC B1825/56, B1826/56, B1827/56 or B1828/56 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1825/56, B1826/56, B1827/56 or B1828/56 is output

    REPLACE AIRBAG ECU ASSEMBLY Click here