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Home >> Lexus >> 2022 >> LC 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 259 (Airbag System - Diagnostic Codes (Coupe) (5 Of 5) & Symptom Tests) >> Airbag System >> DTC B1860/64: Short in Driver Side Knee Airbag Squib Circuit; DTC B1861/64: Open in Driver Side Knee Airbag Squib Circuit; DTC B1862/64: Short to GND in Driver Side Knee Airbag Squib Circuit; DTC B1863/64: Short to B+ in Driver Side Knee Airbag Squib Circuit [03/2017 - 04/2020] >> Procedure

DTC B1860/64: Short in Driver Side Knee Airbag Squib Circuit; DTC B1861/64: Open in Driver Side Knee Airbag Squib Circuit; DTC B1862/64: Short to GND in Driver Side Knee Airbag Squib Circuit; DTC B1863/64: Short to B+ in Driver Side Knee Airbag Squib Circuit [03/2017 - 04/2020]: Procedure

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  1. CHECK CONNECTORS 
    1. Turn the engine switch off.
      GTY741782Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Lower No. 1 Instrument Panel Airbag Assembly
      *2 Airbag ECU Assembly
      *3 Instrument Panel Wire
    2. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    3. Check that the connectors are properly connected to the lower No. 1 instrument panel airbag assembly 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 lower No. 1 instrument panel airbag assembly 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 instrument panel wire connector (on the lower No. 1 instrument panel airbag assembly 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 instrument panel wire connector are not deformed or damaged.

      OK

      The short springs are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL WIRE 

    Result: 

    OK 

    See step  2

  2. CHECK LOWER NO. 1 INSTRUMENT PANEL AIRBAG ASSEMBLY 
    1. Connect the connector to the airbag ECU assembly.
      GTY817242Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Lower No. 1 Instrument Panel Airbag Assembly
      *2 Airbag ECU Assembly
      *3 SST
      *a Front view of wire harness connector
      (to Lower No. 1 Instrument Panel Airbag Assembly)
    2. Connect the white wire side of SST (resistance: 2.1 Ω) to connector C.
      WARNING:

      Never connect the tester to the lower No. 1 instrument panel airbag assembly 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 (-) battery terminal, and wait for at least 2 seconds.
    4. Turn the engine switch on (IG), and wait for at least 60 seconds.
    5. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [03/2017 - 04/2020]

      Body Electrical > SRS Airbag > Clear DTCs 

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

      Refer to DTC CHECK / CLEAR [03/2017 - 04/2020]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B1860/64, B1861/64, B1862/64 or B1863/64 is not output
      DTC B1860/64, B1861/64, B1862/64 or B1863/64 is output

      HINT: 

      Codes other than DTC B1860/64, B1861/64, B1862/64 and B1863/64 may be output at this time, but they are not related to this check.

    9. Turn the engine switch off.
    10. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 seconds.
    11. Disconnect SST from connector C.

    Result: 

    DTC B1860/64, B1861/64, B1862/64 or B1863/64 is not output 

    REPLACE LOWER NO. 1 INSTRUMENT PANEL AIRBAG ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    DTC B1860/64, B1861/64, B1862/64 or B1863/64 is output 

    See step  3

  3. CHECK INSTRUMENT PANEL WIRE 
    1. Disconnect the instrument panel wire from the airbag ECU assembly.
      GTY828911Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Lower No. 1 Instrument Panel Airbag Assembly
      *2 Airbag ECU Assembly
      *3 Instrument Panel Wire
      *a Front view of wire harness connector
      (to Lower No. 1 Instrument Panel Airbag Assembly)
      Release the activation prevention mechanism
    2. Check for a short to B+ in the circuit.
      1. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
      2. Turn the engine switch on (IG).
      3. Measure the voltage according to the value(s) in the table below.

        Standard Voltage

        Tester Connection Switch Condition Specified Condition
        P31-1 (DK+) - Body ground Engine switch on (IG) Below 1 V
        P31-2 (DK-) - Body ground Engine switch on (IG) Below 1 V
      4. Turn the engine switch off.
      5. Disconnect the cable from the negative (-) battery terminal, and wait for at least 90 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
        P31-1 (DK+) - P31-2 (DK-) 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
        P31-1 (DK+) - Body ground Always 1 MΩ or higher
        P31-2 (DK-) - 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 [03/2017 - ]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        P31-1 (DK+) - P31-2 (DK-) 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 INSTRUMENT PANEL WIRE 

    Result: 

    OK 

    See step  4

  4. CHECK DTC 
    1. Connect the connectors to the lower No. 1 instrument panel airbag assembly and airbag ECU assembly.
      GTY825975Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Lower No. 1 Instrument Panel Airbag Assembly
      *2 Airbag ECU Assembly
    2. Connect the cable to the negative (-) battery terminal, and wait for at least 2 seconds.
    3. Turn the engine switch on (IG), and wait for at least 60 seconds.
    4. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [03/2017 - 04/2020]

      Body Electrical > SRS Airbag > Clear DTCs 

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

      Refer to DTC CHECK / CLEAR [03/2017 - 04/2020]

      Body Electrical > SRS Airbag > Trouble Codes 

      Result

      Proceed to
      DTC B1860/64, B1861/64, B1862/64 or B1863/64 is not output
      DTC B1860/64, B1861/64, B1862/64 or B1863/64 is output

      HINT: 

      Codes other than DTC B1860/64, B1861/64, B1862/64 and B1863/64 may be output at this time, but they are not related to this check.

    Result: 

    DTC B1860/64, B1861/64, B1862/64 or B1863/64 is not output 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - 04/2020] 

    Result: 

    DTC B1860/64, B1861/64, B1862/64 or B1863/64 is output 

    REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

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