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Home >> Audi >> 2018 >> A6 Premium Plus >> Repair and Diagnosis >> External Pages >> Different car >> Section 210 (Supplemental Restraint System (Diagnostic Codes & Circuit Tests)) >> Airbag System >> DTC B1920/77: Short in Rear Pretensioner Squib RH Circuit; DTC B1921/77: Open in Rear Pretensioner Squib RH Circuit; DTC B1922/77: Short to GND in Rear Pretensioner Squib RH Circuit; DTC B1923/77: Short to B+ in Rear Pretensioner Squib RH Circuit [08/2013 - ] >> Procedure

DTC B1920/77: Short in Rear Pretensioner Squib RH Circuit; DTC B1921/77: Open in Rear Pretensioner Squib RH Circuit; DTC B1922/77: Short to GND in Rear Pretensioner Squib RH Circuit; DTC B1923/77: Short to B+ in Rear Pretensioner Squib RH Circuit [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK CONNECTORS 
    1. Turn the power switch off.
      GTY321174Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

    3. Check that the connectors are properly connected to the rear seat 3 point type outer belt assembly RH and airbag sensor assembly.

      OK

      The connectors are properly connected.

      HINT: 

      If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

    4. Disconnect the connectors from the rear seat 3 point type outer belt assembly RH and airbag sensor assembly.
    5. Check that the terminals of the connectors are not damaged.

      OK

      The terminals are not deformed or damaged.

    6. Check that the No. 2 floor wire connector (on the rear seat 3 point type outer belt assembly RH side) is not damaged.

      OK

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

    7. Check that the short spring for the No. 2 floor wire with the activation prevention mechanism is not deformed or damaged.

      OK

      The short spring is not deformed or damaged.

      TEXT IN ILLUSTRATION

      *1 Rear Seat 3 Point Type Outer Belt Assembly RH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire

    NG → REPLACE NO. 2 FLOOR WIRE 

    OK: Go to next step 

  2. CHECK REAR SEAT 3 POINT TYPE OUTER BELT ASSEMBLY RH (REAR PRETENSIONER SQUIB RH) 
    1. Connect the connector to the airbag sensor assembly.
      GTY419707Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect SST (resistance 2.1 Ω) to connector C.
      WARNING:

      Never connect the tester to the rear seat 3 point type outer belt assembly RH (rear pretensioner squib RH) for measurement, as this may lead to a serious injury due to pretensioner 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 (-) auxiliary battery terminal.
    4. Clear the DTCs stored in memory. Refer to DTC CHECK / CLEAR [08/2013 - ] .
    5. Turn the power switch off.
    6. Turn the power switch on (IG), and wait for at least 60 seconds.
    7. Check for DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .

      OK

      DTC B1920/77, B1921/77, B1922/77 or B1923/77 is not output.

      HINT: 

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

    8. Turn the power switch off.
    9. Disconnect the cable from the negative (-) auxiliary battery terminal.
      WARNING:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary battery terminal to disable the SRS system.

    10. Disconnect SST from connector C.
      TEXT IN ILLUSTRATION

      *1 Rear Seat 3 Point Type Outer Belt Assembly RH
      *2 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Rear Seat 3 Point Type Outer Belt Assembly RH)

    NG → See step   3 

    OK → See step   7 

  3. CHECK NO. 2 FLOOR WIRE 
    1. Disconnect the No. 2 floor wire from the airbag sensor assembly.
      GTY415708Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check for a short to B+ in the circuit.
      1. Connect the cable to the negative (-) auxiliary battery terminal.
      2. Turn the power switch on (IG).
      3. Measure the voltage according to the value(s) in the table below.

        Standard Voltage

        Tester Connection Condition Specified Condition
        Q23-1 (RR+) - Body ground Power switch on (IG) Below 1 V
        Q23-2 (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.
        WARNING:

        Wait at least 90 seconds after disconnecting the cable from the negative (-) auxiliary 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
        Q23-1 (RR+) - Q23-2 (RR-) 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
        Q23-1 (RR+) - Body ground Always 1 MΩ or higher
        Q23-2 (RR-) - 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. Refer to DIAGNOSIS SYSTEM [08/2013 - ] .
      2. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        Q23-1 (RR+) - Q23-2 (RR-) Always 1 MΩ or higher
      3. Restore the released activation prevention mechanism of connector B to the original condition.
        TEXT IN ILLUSTRATION

        *1 Rear Seat 3 Point Type Outer Belt Assembly RH
        *2 Airbag Sensor Assembly
        *3 No. 2 Floor Wire
        *a Front view of wire harness connector
        (to Rear Seat 3 Point Type Outer Belt Assembly RH)

    NG → REPLACE NO. 2 FLOOR WIRE 

    OK: Go to next step 

  4. CHECK DTC 
    1. Connect the connectors to the rear seat 3 point type outer belt assembly RH and airbag sensor assembly.
      GTY319562Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Clear the DTCs stored in memory. Refer to DTC CHECK / CLEAR [08/2013 - ] .
    4. Turn the power switch off.
    5. Turn the power switch on (IG), and wait for at least 60 seconds.
    6. Check for DTCs. Refer to DTC CHECK / CLEAR [08/2013 - ] .

      OK

      DTC B1920/77, B1921/77, B1922/77 or B1923/77 is not output.

      HINT: 

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

      TEXT IN ILLUSTRATION

      *1 Rear Seat 3 Point Type Outer Belt Assembly RH
      *2 Airbag Sensor Assembly

    NG → See step   6 

    OK → See step   5 

  5. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2013 - ] 
  6. REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [08/2013 - ] 
  7. REPLACE REAR SEAT 3 POINT TYPE OUTER BELT ASSEMBLY RH. Refer to  REMOVAL [08/2013 - ] 
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