AIRBAG SYSTEM, Diagnostic DTC:B1925/78, B1926/78, B1927/78, B1928/78

DTC Code DTC Name
B1925/78 Short in Rear Pretensioner Squib LH Circuit
B1926/78 Open in Rear Pretensioner Squib LH Circuit
B1927/78 Short to GND in Rear Pretensioner Squib LH Circuit
B1928/78 Short to B+ in Rear Pretensioner Squib LH Circuit

DESCRIPTION

The rear seat belt pretensioner LH circuit consists of the center airbag sensor assembly and rear seat 3 point type 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 rear seat belt pretensioner LH circuit.

DTC Code DTC Detection Condition Trouble Area
B1925/78

One of the following conditions is met:


  • The center airbag sensor assembly detects a line short circuit signal 5 times in the rear seat belt pretensioner LH circuit during the primary check.

  • A rear seat belt pretensioner LH malfunction.

  • A center airbag sensor assembly malfunction.

  • No. 2 floor wire

  • Rear seat 3 point type outer belt assembly LH (Rear seat belt pretensioner LH)

  • Center airbag sensor assembly
B1926/78

One of the following conditions is met:


  • The center airbag sensor assembly detects an open circuit signal in the rear seat belt pretensioner LH circuit for 2 seconds.

  • A rear seat belt pretensioner LH malfunction.

  • A center airbag sensor assembly malfunction.
B1927/78

One of the following conditions is met:


  • The center airbag sensor assembly detects a short circuit to ground signal in the rear seat belt pretensioner LH circuit for 0.5 seconds.

  • A rear seat belt pretensioner LH malfunction.

  • A center airbag sensor assembly malfunction.
B1928/78

One of the following conditions is met:


  • The center airbag sensor assembly detects a short circuit to B+ signal in the rear seat belt pretensioner LH circuit for 0.5 seconds.

  • A rear seat belt pretensioner LH malfunction.

  • A center airbag sensor assembly malfunction.

WIRING DIAGRAM

A01FTIKE21

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 Click 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 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 REAR SEAT 3 POINT TYPE OUTER BELT ASSEMBLY LH (REAR SEAT BELT PRETENSIONER LH)


    1. A01FUV1E08
      Text in Illustration
      *1 Rear Seat Belt Pretensioner LH
      *2 Center Airbag Sensor Assembly
      *3 Connector C
      *4 SST
      *a

      Front view of wire harness connector

      (to Rear Seat Belt Pretensioner LH)

      Turn the power switch off.

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

    3. Disconnect the connectors from the rear seat 3 point type 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 rear seat 3 point type outer belt assembly LH (rear seat belt pretensioner 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 (-) auxiliary battery terminal, and wait for at least 2 seconds.

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

    7. Clear the DTCs Click here.

    8. Turn the power switch off.

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

    10. Check for DTCs Click here.

      OK
      DTC B1925/78, B1926/78, B1927/78 or B1928/78 is not output.

      Tech Tips

      Codes other than DTC B1925/78, B1926/78, B1927/78 and B1928/78 may be output at this time, but they are not related to this check.

    11. Turn the power switch off.

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

    13. Disconnect SST from connector C.


    NG

    CHECK CONNECTOR Click here

    OK

    REPLACE REAR SEAT 3 POINT TYPE OUTER BELT ASSEMBLY LH Click here

  2. CHECK CONNECTOR


    1. Disconnect the connectors from the center airbag sensor assembly.

    2. A01FUG4E01
      Text in Illustration
      *1 Rear Seat Belt Pretensioner LH
      *2 No. 2 Floor Wire
      *3 Center Airbag Sensor Assembly

      Check that the connectors (on the center airbag sensor assembly side and rear seat 3 point type 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.

    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  3. CHECK REAR SEAT BELT PRETENSIONER LH CIRCUIT


    1. A01FRY4E08
      Text in Illustration
      *1 Rear Seat Belt Pretensioner LH
      *2 No. 2 Floor Wire
      *3 Center Airbag Sensor Assembly
      *4 Connector C
      *a

      Front view of wire harness connector

      (to Rear Seat Belt Pretensioner LH)

      Connect the cable to the negative (-) auxiliary battery terminal, 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
      U25-1 (RL+) - Body ground Power switch on (IG) Below 1 V
      U25-2 (RL-) - Body ground Power switch on (IG) Below 1 V

    4. Turn the power switch off.

    5. Disconnect the cable from the negative (-) auxiliary 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
      U25-1 (RL+) - U25-2 (RL-) 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
      U25-1 (RL+) - U25-2 (RL-) Always 1 MΩ or higher
      U25-1 (RL+) - Body ground Always 1 MΩ or higher
      U25-2 (RL-) - Body ground Always 1 MΩ or higher

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


    NG

    REPLACE NO. 2 FLOOR WIRE

    OK

  4. CHECK CENTER AIRBAG SENSOR ASSEMBLY


    1. A01FTSPE37
      Text in Illustration
      *1 Rear Seat Belt Pretensioner LH
      *2 Center Airbag Sensor Assembly

      Connect the connectors to the rear seat 3 point type outer belt assembly LH and center airbag sensor assembly.

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

      OK
      DTC B1925/78, B1926/78, B1927/78 or B1928/78 is not output.

      Tech Tips

      Codes other than DTC B1925/78, B1926/78, B1927/78 and B1928/78 may be output at this time, but they are not related to this check.


    NG

    REPLACE CENTER AIRBAG SENSOR ASSEMBLY Click here

    OK

    USE SIMULATION METHOD TO CHECK Click here