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Home >> Lexus >> 2022 >> RX 450hL >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System (Diagnostic Codes) (5 Of 5) & Symptom Tests) >> Airbag System >> DTC B1855-63: Short in Rear Side Squib LH Circuit; DTC B1856-63: Open in Rear Side Squib LH Circuit; DTC B1857-63: Short to GND in Rear Side Squib LH Circuit; DTC B1858-63: Short to B+ in Rear Side Squib LH Circuit [03/2018 - 08/2019] >> Procedure

DTC B1855-63: Short in Rear Side Squib LH Circuit; DTC B1856-63: Open in Rear Side Squib LH Circuit; DTC B1857-63: Short to GND in Rear Side Squib LH Circuit; DTC B1858-63: Short to B+ in Rear Side Squib LH Circuit [03/2018 - 08/2019]: Procedure

  1. CHECK VEHICLE CONDITION 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w/o Rear No. 2 Seat A
      w/ Rear No. 2 Seat B

    Result: 

    B 

    See step  6

    Result: 

    A 

    See step  2

  2. CHECK CONNECTORS 
    1. Turn the power switch off.
      GTY451104Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
    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 airbag assembly LH and airbag sensor assembly.

      OK

      The connectors are properly connected.

      HINT: 

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

    4. Disconnect the connectors from the rear seat airbag assembly LH and airbag sensor assembly.
    5. Check that the terminals of the connectors are not deformed or damaged.

      OK

      The terminals are not deformed or damaged.

    6. Check that the short springs of the activation prevention mechanism of the No. 2 floor wire connector are not deformed or damaged.

      OK

      The short springs are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    OK 

    See step  3

  3. CHECK REAR SEAT AIRBAG ASSEMBLY LH 
    1. Connect the connector to the airbag sensor assembly.
      GTY653997Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Rear Seat Airbag Assembly LH)
    2. Connect SST (resistance 2.1 Ω) to connector C.
      WARNING:

      Never connect a tester to the rear 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 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 [10/2015 - 08/2019]

      Body Electrical > SRS Airbag > Clear DTCs 

    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 [10/2015 - 08/2019]

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1855-63, B1856-63, B1857-63 or B1858-63 is not output.

      HINT: 

      Codes other than DTCs B1855-63, B1856-63, B1857-63 and B1858-63 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.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR SEAT AIRBAG ASSEMBLY LH. Refer to  REMOVAL [08/2016 - 08/2019] 

    Result: 

    NG 

    See step  4

  4. CHECK NO. 2 FLOOR WIRE 
    1. Disconnect the No. 2 floor wire from the airbag sensor assembly.
      GTY618677Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *3 No. 2 Floor Wire
      *a Front view of wire harness connector
      (to Rear Seat Airbag Assembly LH)
    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
        S19-1 (SRL+) - Body ground Power switch on (IG) Below 1 V
        S19-2 (SRL-) - 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
        S19-1 (SRL+) - S19-2 (SRL-) 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
        S19-1 (SRL+) - Body ground Always 1 MΩ or higher
        S19-2 (SRL-) - 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 [03/2018 - 08/2019]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        S19-1 (SRL+) - S19-2 (SRL-) Always 1 MΩ or higher
      3. Restore the released activation prevention mechanism of connector B to the original condition.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    OK 

    See step  5

  5. CHECK DTC 
    1. Connect the connectors to the rear seat airbag assembly LH and airbag sensor assembly.
      GTY437079Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Clear the DTCs stored in memory.

      Refer to DTC CHECK / CLEAR [10/2015 - 08/2019]

      Body Electrical > SRS Airbag > Clear DTCs 

    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 [10/2015 - 08/2019]

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1855-63, B1856-63, B1857-63 or B1858-63 is not output.

      HINT: 

      Codes other than DTCs B1855-63, B1856-63, B1857-63 and B1858-63 may be output at this time, but they are not related to this check.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2018 - 08/2019] 

    Result: 

    NG 

    REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [03/2018 - 08/2019] 

  6. CHECK CONNECTORS 
    1. Turn the power switch off.
      GTY454799Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *3 Rear Seat Wire LH
      *4 No. 2 Floor Wire
    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 airbag assembly LH and airbag sensor assembly. Also check that the connectors that link the No. 2 floor wire and rear seat wire LH are properly connected.

      OK

      The connectors are properly connected.

      HINT: 

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

    4. Disconnect the connectors from the rear seat airbag assembly LH and airbag sensor assembly. Also disconnect the No. 2 floor wire from the rear seat wire LH.
    5. Check that the terminals of the connectors are not deformed or damaged.

      OK

      The terminals are not deformed or damaged.

    6. Check that the short springs of the activation prevention mechanisms of the No. 2 floor wire connector and rear seat wire LH connector are not deformed or damaged.

      OK

      The short springs are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE WIRE HARNESS 

    Result: 

    OK 

    See step  7

  7. CHECK REAR SEAT AIRBAG ASSEMBLY LH 
    1. Connect the No. 2 floor wire to the rear seat wire LH and airbag sensor assembly.
      GTY780749Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Rear Seat Airbag Assembly LH)
    2. Connect SST (resistance 2.1 Ω) to connector E.
      WARNING:

      Never connect a tester to the rear 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 it.
      • Insert SST straight into the terminals of the connector.
      • SST: 09843-18061 
    3. Connect the cable to the negative (-) auxiliary battery terminal.
    4. Turn the power switch on (IG), and wait for at least 60 seconds.
    5. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    6. Turn the power switch off.
    7. Turn the power switch on (IG), and wait for at least 60 seconds.
    8. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1855-63, B1856-63, B1857-63 or B1858-63 is not output.

      HINT: 

      Codes other than DTCs B1855-63, B1856-63, B1857-63 and B1858-63 may be output at this time, but they are not related to this check.

    9. Turn the power switch off.
    10. 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.

    11. Disconnect SST from connector E.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR SEAT AIRBAG ASSEMBLY LH. Refer to  REMOVAL [03/2018 - 08/2019] 

    Result: 

    NG 

    See step  8

  8. CHECK WIRE HARNESS (AIRBAG SENSOR ASSEMBLY - REAR SEAT AIRBAG ASSEMBLY LH) 
    1. Disconnect the No. 2 floor wire from the airbag sensor assembly.
      GTY779966Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Rear Seat Airbag Assembly LH)
    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
        y9-1 (SRL+) - Body ground Power switch on (IG) Below 1 V
        y9-2 (SRL-) - 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
        y9-1 (SRL+) - y9-2 (SRL-) 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
        y9-1 (SRL+) - Body ground Always 1 MΩ or higher
        y9-2 (SRL-) - 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 [03/2018 - 08/2019]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        y9-1 (SRL+) - y9-2 (SRL-) Always 1 MΩ or higher
      3. Restore the released activation prevention mechanism of connector B to the original condition.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  9

  9. CHECK DTC 
    1. Connect the connectors to the rear seat airbag assembly LH and airbag sensor assembly.
      GTY796773Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Turn the power switch on (IG), and wait for at least 60 seconds.
    4. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    5. Turn the power switch off.
    6. Turn the power switch on (IG), and wait for at least 60 seconds.
    7. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1855-63, B1856-63, B1857-63 or B1858-63 is not output.

      HINT: 

      Codes other than DTCs B1855-63, B1856-63, B1857-63 and B1858-63 may be output at this time, but they are not related to this check.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2018 - 08/2019] 

    Result: 

    NG 

    REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [03/2018 - 08/2019] 

  10. CHECK NO. 2 FLOOR WIRE 
    1. Disconnect the rear seat wire LH from the No. 2 floor wire.
      GTY831329Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *3 Rear Seat Wire LH
      *4 No. 2 Floor Wire
      *a Front view of wire harness connector
      (to Rear Seat Wire LH)
    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
        Sy3-1 (SRL+) - Body ground Power switch on (IG) Below 1 V
        Sy3-2 (SRL-) - 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
        Sy3-1 (SRL+) - Sy3-2 (SRL-) 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
        Sy3-1 (SRL+) - Body ground Always 1 MΩ or higher
        Sy3-2 (SRL-) - 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 [03/2018 - 08/2019]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        Sy3-1 (SRL+) - Sy3-2 (SRL-) Always 1 MΩ or higher
      3. Restore the released activation prevention mechanism of connector B to the original condition.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE NO. 2 FLOOR WIRE 

    Result: 

    OK 

    See step  11

  11. CHECK REAR SEAT WIRE LH 
    1. Check for a short to B+ in the circuit.
      GTY834921Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag Sensor Assembly
      *3 Rear Seat Wire LH
      *4 No. 2 Floor Wire
      *a Front view of wire harness connector
      (to Rear Seat Airbag Assembly LH)
      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
        y9-1 (SRL+) - Body ground Power switch on (IG) Below 1 V
        y9-2 (SRL-) - 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.

    2. 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
        y9-1 (SRL+) - y9-2 (SRL-) Always Below 1 Ω
    3. 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
        y9-1 (SRL+) - Body ground Always 1 MΩ or higher
        y9-2 (SRL-) - Body ground Always 1 MΩ or higher
    4. Check for a short in the circuit.
      1. Release the activation prevention mechanism built into connector D.

        Refer to DIAGNOSIS SYSTEM [03/2018 - 08/2019]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        y9-1 (SRL+) - y9-2 (SRL-) Always 1 MΩ or higher
      3. Restore the released activation prevention mechanism of connector D to the original condition.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2018 - 08/2019] 

    Result: 

    NG 

    REPLACE REAR SEAT WIRE LH 

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