AIRBAG SYSTEM, Diagnostic DTC:B1905/74, B1906/74, B1907/74, B1908/74

DTC Code DTC Name
B1905/74 Short in Front Pretensioner Squib LH Circuit
B1906/74 Open in Front Pretensioner Squib LH Circuit
B1907/74 Short to GND in Front Pretensioner Squib LH Circuit
B1908/74 Short to B+ in Front Pretensioner Squib LH Circuit

DESCRIPTION

The front pretensioner LH circuit consists of the airbag ECU assembly and front seat outer belt assembly LH.

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

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

DTC No. Detection Item DTC Detection Condition Trouble Area
B1905/74 Short in Front Pretensioner 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 pretensioner LH circuit during the primary check.

  • A front seat outer belt assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Front seat outer belt assembly LH

  • Airbag ECU assembly

  • No. 2 front seat wire LH*

  • Front seat inner belt assembly LH*
B1906/74 Open in Front Pretensioner Squib LH Circuit

One of the following conditions is met:


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

  • A front seat outer belt assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Front seat outer belt assembly LH

  • Airbag ECU assembly

  • No. 2 front seat wire LH*

  • Front seat inner belt assembly LH*
B1907/74 Short to GND in Front Pretensioner Squib LH Circuit

One of the following conditions is met:


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

  • A front seat outer belt assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Front seat outer belt assembly LH

  • Airbag ECU assembly

  • No. 2 front seat wire LH*

  • Front seat inner belt assembly LH*
B1908/74 Short to B+ in Front Pretensioner Squib LH Circuit

One of the following conditions is met:


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

  • A front seat outer belt assembly LH malfunction.

  • An airbag ECU assembly malfunction.

  • Floor wire

  • Front seat outer belt assembly LH

  • Airbag ECU assembly

  • No. 2 front seat wire LH*

  • Front seat inner belt assembly LH*

WIRING DIAGRAM

Figure 1. except Super Long Slide Seat:

B006Q5SE81
*a Front Seat Outer Belt Assembly LH
*b Airbag ECU Assembly

Figure 2. for Super Long Slide Seat:

B006NYVE07
*a Front Seat Outer Belt Assembly LH
*b 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 VEHICLE TYPE


    1. Check vehicle type.

      Result
      Proceed to
      except Super Long Slide Seat
      for Super Long Slide Seat

    for Super Long Slide Seat

    CHECK FRONT SEAT OUTER BELT ASSEMBLY LH Click here

    except Super Long Slide Seat

  2. CHECK FRONT SEAT OUTER BELT ASSEMBLY LH


    1. B006PRXC18
      *1 Front Seat Outer Belt Assembly LH
      *2 Airbag ECU Assembly
      *3 Connector C
      *4 SST
      *a

      Front view of wire harness connector

      (to Front Seat Outer Belt 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 outer belt assembly LH.

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

      CAUTION:

      Never connect the tester to the front seat outer belt 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 B1905/74, B1906/74, B1907/74 or B1908/74 is not output
      DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

      Tech Tips

      Codes other than DTC B1905/74, B1906/74, B1907/74 and B1908/74 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 B1905/74, B1906/74, B1907/74 or B1908/74 is not output

    REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH Click here

    DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

  3. CHECK CONNECTORS


    1. Disconnect the connectors from the airbag ECU assembly.

    2. B006NDDC02
      *1 Front Seat Outer Belt Assembly LH
      *2 Floor Wire
      *3 Airbag ECU Assembly

      Check that the connectors (on the airbag ECU assembly side and front seat outer belt 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 FLOOR WIRE

    OK

  4. CHECK FLOOR WIRE


    1. B006QQEC20
      *1 Front Seat Outer Belt Assembly LH
      *2 Floor Wire
      *3 Airbag ECU Assembly
      *4 Connector C
      *a

      Front view of wire harness connector

      (to Front Seat Outer Belt 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
      K12-1 (L+) - Body ground Engine switch on (IG) Below 1 V
      K12-2 (L-) - 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
      K12-1 (L+) - K12-2 (L-) 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
      K12-1 (L+) - K12-2 (L-) 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
      K12-1 (L+) - Body ground Always 1 MΩ or higher
      K12-2 (L-) - Body ground Always 1 MΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FLOOR WIRE

    OK

  5. CHECK DTC


    1. B006NT3C09
      *1 Front Seat Outer Belt Assembly LH
      *2 Airbag ECU Assembly

      Connect the connectors to the front seat outer belt 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 B1905/74, B1906/74, B1907/74 or B1908/74 is not output
      DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

      Tech Tips

      Codes other than DTC B1905/74, B1906/74, B1907/74 and B1908/74 may be output at this time, but they are not related to this check.


    DTC B1905/74, B1906/74, B1907/74 or B1908/74 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

    REPLACE AIRBAG ECU ASSEMBLY w/ Navigation System: REPLACE AIRBAG ECU ASSEMBLY Click here
    REPLACE AIRBAG ECU ASSEMBLY w/o Navigation System: REPLACE AIRBAG ECU ASSEMBLY Click here

  6. CHECK FRONT SEAT OUTER BELT ASSEMBLY LH


    1. B006QQVC01
      *1 Front Seat Outer Belt Assembly LH
      *2 Airbag ECU Assembly
      *3 Connector C
      *4 SST
      *a

      Front view of wire harness connector

      (to Front Seat Outer Belt 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 outer belt assembly LH.

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

      CAUTION:

      Never connect the tester to the front seat outer belt 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 B1905/74, B1906/74, B1907/74 or B1908/74 is not output
      DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

      Tech Tips

      Codes other than DTC B1905/74, B1906/74, B1907/74 and B1908/74 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 B1905/74, B1906/74, B1907/74 or B1908/74 is not output

    REPLACE FRONT SEAT OUTER BELT ASSEMBLY LH Click here

    DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

  7. CHECK CONNECTORS


    1. Disconnect the connectors from the airbag ECU assembly.

    2. B006NE4C01
      *1 Front Seat Outer Belt Assembly LH
      *2 Airbag ECU Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 No. 2 Front Seat Wire LH
      *5 Floor Wire

      Check that the connectors (on the airbag ECU assembly side and front seat outer belt 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 FLOOR WIRE OR FRONT SEAT INNER BELT ASSEMBLY LH

    OK

  8. CHECK FRONT SEAT OUTER BELT ASSEMBLY LH


    1. B006PQ9C01
      *1 Front Seat Outer Belt Assembly LH
      *2 Airbag ECU Assembly
      *3 Connector G
      *a

      Front view of wire harness connector

      (to Front Seat Outer Belt 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
      z13-4 (L+) - Body ground Engine switch on (IG) Below 1 V
      z13-3 (L-) - 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
      z13-4 (L+) - z13-3 (L-) 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
      z13-4 (L+) - z13-3 (L-) 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
      z13-4 (L+) - Body ground Always 1 MΩ or higher
      z13-3 (L-) - Body ground Always 1 MΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    CHECK FRONT PRETENSIONER SQUIB LH CIRCUIT Click here

    OK

  9. CHECK DTC


    1. B006MGMC02
      *1 Front Seat Outer Belt Assembly LH
      *2 Airbag ECU Assembly

      Connect the connectors to the front seat outer belt 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 B1905/74, B1906/74, B1907/74 or B1908/74 is not output
      DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

      Tech Tips

      Codes other than DTC B1905/74, B1906/74, B1907/74 and B1908/74 may be output at this time, but they are not related to this check.


    DTC B1905/74, B1906/74, B1907/74 or B1908/74 is not output

    USE SIMULATION METHOD TO CHECK Click here

    DTC B1905/74, B1906/74, B1907/74 or B1908/74 is output

    REPLACE AIRBAG ECU ASSEMBLY w/ Navigation System: REPLACE AIRBAG ECU ASSEMBLY Click here
    REPLACE AIRBAG ECU ASSEMBLY w/o Navigation System: REPLACE AIRBAG ECU ASSEMBLY Click here

  10. CHECK FRONT PRETENSIONER SQUIB LH CIRCUIT


    1. B006KLQC02
      *1 Front Seat Outer Belt Assembly LH
      *2 Front Seat Inner Belt Assembly LH
      *3 Airbag ECU Assembly
      *4 Connector E
      *a

      Front view of wire harness connector

      (to Front Seat Inner Belt 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
      X5-1 (L+) - Body ground Engine switch on (IG) Below 1 V
      X5-2 (L-) - 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
      X5-1 (L+) - X5-2 (L-) 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
      X5-1 (L+) - X5-2 (L-) 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
      X5-1 (L+) - Body ground Always 1 MΩ or higher
      X5-2 (L-) - Body ground Always 1 MΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FRONT SEAT INNER BELT ASSEMBLY LH Click here

    NG

  11. CHECK FLOOR WIRE


    1. B006PJYC03
      *1 Front Seat Outer Belt Assembly LH
      *2 Front Seat Inner Belt Assembly LH
      *3 No. 2 Front Seat Wire LH
      *4 Floor Wire
      *5 Airbag ECU Assembly
      *6 Connector C
      *a

      Front view of wire harness connector

      (to No. 2 Front Seat Wire 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
      XK2-1 (PL+) - Body ground Engine switch on (IG) Below 1 V
      XK2-2 (PL-) - 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
      XK2-1 (PL+) - XK2-2 (PL-) 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
      XK2-1 (PL+) - XK2-2 (PL-) 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
      XK2-1 (PL+) - Body ground Always 1 MΩ or higher
      XK2-2 (PL-) - Body ground Always 1 MΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 FRONT SEAT WIRE LH

    NG

    REPLACE FLOOR WIRE