AIRBAG SYSTEM, Diagnostic DTC:B1920/77, B1921/77, B1922/77, B1923/77

DTC Code DTC Name
B1920/77 Short in Rear Pretensioner Squib RH Circuit
B1921/77 Open in Rear Pretensioner Squib RH Circuit
B1922/77 Short to GND in Rear Pretensioner Squib RH Circuit
B1923/77 Short to B+ in Rear Pretensioner Squib RH Circuit

DESCRIPTION

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

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 RH circuit.

DTC Code DTC Detection Condition Trouble Area
B1920/77

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 RH circuit during the primary check.

  • A rear seat belt pretensioner RH malfunction.

  • A center airbag sensor assembly malfunction.


  • Floor wire

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

  • Center airbag sensor assembly

B1921/77

One of the following conditions is met:


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

  • A rear seat belt pretensioner RH malfunction.

  • A center airbag sensor assembly malfunction.

B1922/77

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 RH circuit for 0.5 seconds.

  • A rear seat belt pretensioner RH malfunction.

  • A center airbag sensor assembly malfunction.

B1923/77

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 RH circuit for 0.5 seconds.

  • A rear seat belt pretensioner RH malfunction.

  • A center airbag sensor assembly malfunction.

WIRING DIAGRAM

A01FTIKE20

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 RH (REAR SEAT BELT PRETENSIONER RH)


    1. A01FSW2E07
      Text in Illustration
      *1 Rear Seat Belt Pretensioner RH
      *2 Center Airbag Sensor Assembly
      *3 Connector C
      *4 SST
      *a

      Front view of wire harness connector

      (to Rear Seat Belt Pretensioner RH)

      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 RH.

    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 RH (rear seat belt pretensioner RH) 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 B1920/77, B1921/77, B1922/77 or B1923/77 is not output.

      Tech Tips

      Codes other than DTC B1920/77, B1921/77, B1922/77 and B1923/77 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
    OK
  2. CHECK CONNECTOR


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

    2. A01FSPXE01
      Text in Illustration
      *1 Rear Seat Belt Pretensioner RH
      *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 RH side) are not damaged.

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

    NG
    OK
  3. CHECK REAR SEAT BELT PRETENSIONER RH CIRCUIT


    1. A01FQWZE06
      Text in Illustration
      *1 Rear Seat Belt Pretensioner RH
      *2 Floor Wire
      *3 Center Airbag Sensor Assembly
      *4 Connector C
      *a

      Front view of wire harness connector

      (to Rear Seat Belt Pretensioner RH)

      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
      T26-1 (RR+) - Body ground Power switch on (IG) Below 1 V
      T26-2 (RR-) - 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
      T26-1 (RR+) - T26-2 (RR-) 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
      T26-1 (RR+) - T26-2 (RR-) Always 1 MΩ or higher
      T26-1 (RR+) - Body ground Always 1 MΩ or higher
      T26-2 (RR-) - Body ground Always 1 MΩ or higher
    9. Restore the released activation prevention mechanism of connector B to its original condition.


    NG
    OK
  4. CHECK CENTER AIRBAG SENSOR ASSEMBLY


    1. A01FQG3E25
      Text in Illustration
      *1 Rear Seat Belt Pretensioner RH
      *2 Center Airbag Sensor Assembly

      Connect the connectors to the rear seat 3 point type outer belt assembly RH 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 stored in memory 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 B1920/77, B1921/77, B1922/77 or B1923/77 is not output.

      Tech Tips

      Codes other than DTC B1920/77, B1921/77, B1922/77 and B1923/77 may be output at this time, but they are not related to this check.


    NG
    OK