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Home >> Lexus >> 2021 >> LS 500h RWD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System (W/O Advanced Park) - Diagnostic Codes (3 Of 3) >> AIRBAG SYSTEM (w/o Advanced Park) >> DTC B1885: Short in Rear Seat Cushion Squib LH Circuit; DTC B1886: Open in Rear Seat Cushion Squib LH Circuit; DTC B1887: Short to GND in Rear Seat Cushion Squib LH Circuit; DTC B1888: Short to B+ in Rear Seat Cushion Squib LH Circuit [10/2020 - 10/2023] >> Procedure

DTC B1885: Short in Rear Seat Cushion Squib LH Circuit; DTC B1886: Open in Rear Seat Cushion Squib LH Circuit; DTC B1887: Short to GND in Rear Seat Cushion Squib LH Circuit; DTC B1888: Short to B+ in Rear Seat Cushion Squib LH Circuit [10/2020 - 10/2023]: Procedure

  1. CHECK CONNECTORS 
    1. Turn the power switch off.
      GTY797821Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Cushion Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire
    2. Disconnect the cable from the negative (-) auxiliary battery terminal, and wait for at least 60 seconds.
    3. Check that the connectors are properly connected to the rear seat cushion airbag assembly LH and airbag ECU 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 cushion airbag assembly LH and airbag ECU 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 floor wire connector (on the rear seat cushion airbag assembly LH side) is not loose, deformed or damaged.

      OK

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

    7. Check that the short springs of the activation prevention mechanism of the 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 FLOOR WIRE OR REAR SEAT WIRE LH 

    Result: 

    OK 

    See step  2

  2. CHECK REAR SEAT CUSHION AIRBAG ASSEMBLY LH 
    1. Connect the connector to the airbag ECU assembly.
      GTY779451Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Cushion Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 SST
      *a Front view of wire harness connector
      (to Rear Seat Cushion Airbag Assembly LH)
    2. Connect the black wire side of SST (resistance: 2.1 Ω) to connector E.
      WARNING:

      Never connect the tester to the rear seat cushion 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 SST.
      • Insert SST straight into the terminals of the connector.
      • SST: 09843-18061 
    3. Connect the cable to the negative (-) auxiliary battery terminal, and wait for at least 2 seconds.
    4. Turn the power switch on (IG), and wait for at least 60 seconds.
    5. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [10/2020 - 10/2023]

      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.

      Refer to DTC CHECK / CLEAR [10/2020 - 10/2023]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B1885, B1886, B1887 and B1888 are not output
      DTC B1885, B1886, B1887 or B1888 is output

      HINT: 

      Codes other than DTC B1885, B1886, B1887 and B1888 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, and wait for at least 60 seconds.
    11. Disconnect SST from connector E.

    Result: 

    DTC B1885, B1886, B1887 and B1888 are not output 

    REPLACE REAR SEAT CUSHION AIRBAG ASSEMBLY LH. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

    Result: 

    DTC B1885, B1886, B1887 or B1888 is output 

    See step  3

  3. CHECK REAR SEAT CUSHION AIRBAG ASSEMBLY CIRCUIT LH 
    1. Disconnect the floor wire from the airbag ECU assembly.
      GTY800572Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Cushion Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Rear Seat Wire LH
      *4 Floor Wire
      *a Front view of wire harness connector
      (to Rear Seat Cushion Airbag Assembly LH)
      Release the activation prevention mechanism
    2. Check for a short to B+ in the circuit.
      1. 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
        R52-1 - Body ground Power switch on (IG) Below 1 V
        R52-2 - 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 60 seconds.
    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
        R52-1 - R52-2 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
        R52-1 - Body ground Always 1 MΩ or higher
        R52-2 - 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 SYSTEM DESCRIPTION [10/2020 - 10/2023]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        R52-1 - R52-2 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  5

    Result: 

    OK 

    See step  4

  4. CHECK DTC 
    1. Connect the connectors to the curtain shield airbag assembly LH and airbag ECU assembly.
      GTY821150Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Cushion Airbag Assembly LH
      *2 Airbag ECU 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.

      Refer to DTC CHECK / CLEAR [10/2020 - 10/2023]

      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 [10/2020 - 10/2023]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B1885, B1886, B1887 and B1888 are not output
      DTC B1885, B1886, B1887 or B1888 is output

      HINT: 

      Codes other than DTC B1885, B1886, B1887 and B1888 may be output at this time, but they are not related to this check.

    Result: 

    DTC B1885, B1886, B1887 and B1888 are not output 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 10/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - 10/2023] 

    Result: 

    DTC B1885, B1886, B1887 or B1888 is output 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [10/2020 - 11/2021]  , or refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

  5. CHECK FLOOR WIRE 
    1. Disconnect the floor wire from the rear seat wire LH.
      GTY803748Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Rear Seat Airbag Assembly LH
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *4 Rear Seat Wire LH
      *a Front view of wire harness connector
      (to Rear Seat Airbag Assembly LH)
      Release the activation prevention mechanism
    2. Check for a short to B+ in the circuit.
      1. 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 Condition Specified Condition
        LR 8-1 (RCL+) - Body ground Power switch on (IG) Below 1 V
        LR 8-2 (RCL-) - 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.
    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
        LR 8-1 (RCL+) - LR 8-2 (RCL-) 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
        LR 8-1 (RCL+) - Body ground Always 1 MΩ or higher
        LR 8-2 (RCL-) - 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 SYSTEM DESCRIPTION [10/2020 - 10/2023]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        LR 8-1 (RCL+) - LR 8-2 (RCL-) 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: 

    OK 

    REPLACE REAR SEAT WIRE LH 

    Result: 

    NG 

    REPLACE FLOOR WIRE 

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