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Home >> Lexus >> 2021 >> LC 500 2D Coupe >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (Coupe) (3 Of 5) >> Airbag System >> DTC B1805/52: Short in Front Passenger Side Squib Circuit; DTC B1806/52: Open in Front Passenger Side Squib Circuit; DTC B1807/52: Short to GND in Front Passenger Side Squib Circuit; DTC B1808/52: Short to B+ in Front Passenger Side Squib Circuit [03/2017 - 04/2020] >> Procedure

DTC B1805/52: Short in Front Passenger Side Squib Circuit; DTC B1806/52: Open in Front Passenger Side Squib Circuit; DTC B1807/52: Short to GND in Front Passenger Side Squib Circuit; DTC B1808/52: Short to B+ in Front Passenger Side Squib Circuit [03/2017 - 04/2020]: Procedure

  1. CHECK CONNECTORS 
    1. Turn the engine switch off.
      GTY833278Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Instrument Panel Passenger Airbag Assembly
      *2 Airbag ECU Assembly
      *3 No. 3 Instrument Panel Wire
      *4 Instrument Panel Wire
    2. Disconnect the cable from the negative (-) battery terminal.
      WARNING:

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

    3. Check that the connectors are properly connected to the instrument panel passenger airbag assembly and airbag ECU assembly. Also check that the connectors that link the instrument panel wire and No. 3 instrument panel wire 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 instrument panel passenger airbag assembly and airbag ECU assembly. Also disconnect the instrument panel wire from the No. 3 instrument panel wire.
    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 No. 3 instrument panel wire connector (on the instrument panel passenger 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 mechanisms of the instrument panel wire connector and No. 3 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 OR NO. 2 INSTRUMENT PANEL WIRE 

    Result: 

    OK 

    See step  2

  2. CHECK INSTRUMENT PANEL PASSENGER AIRBAG ASSEMBLY 
    1. Connect the instrument panel wire to the No. 3 instrument panel wire and airbag ECU assembly.
      GTY827154Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Instrument Panel Passenger Airbag Assembly
      *2 Airbag ECU Assembly
      *3 SST
      *a Front view of wire harness connector
      (to Instrument Panel Passenger Airbag Assembly)
      *b Color: Orange
    2. Connect the white wire side of SST (resistance: 2.1 Ω) to connector E (orange connector).
      WARNING:

      Never connect the tester to the instrument panel passenger 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 B1805/52, B1806/52, B1807/52 or B1808/52 is not output
      DTC B1805/52, B1806/52, B1807/52 or B1808/52 is output

      HINT: 

      Codes other than DTC B1805/52, B1806/52, B1807/52 and B1808/52 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 E.

    Result: 

    DTC B1805/52, B1806/52, B1807/52 or B1808/52 is not output 

    REPLACE INSTRUMENT PANEL PASSENGER AIRBAG ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    DTC B1805/52, B1806/52, B1807/52 or B1808/52 is output 

    See step  3

  3. CHECK FRONT PASSENGER SIDE SQUIB CIRCUIT 
    1. Disconnect the instrument panel wire from the airbag ECU assembly.
      GTY793537Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Instrument Panel Passenger Airbag Assembly
      *2 Airbag ECU Assembly
      *a Front view of wire harness connector
      (to Instrument Panel Passenger Airbag Assembly)
      *b Color: Orange
      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
        B1-1 (P-) - Body ground Engine switch on (IG) Below 1 V
        B1-2 (P+) - 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
        B1-1 (P-) - B1-2 (P+) 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
        B1-1 (P-) - Body ground Always 1 MΩ or higher
        B1-2 (P+) - 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
        B1-1 (P-) - B1-2 (P+) 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 instrument panel passenger airbag assembly and airbag ECU assembly.
      GTY793178Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Instrument Panel Passenger 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 B1805/52, B1806/52, B1807/52 or B1808/52 is not output
      DTC B1805/52, B1806/52, B1807/52 or B1808/52 is output

      HINT: 

      Codes other than DTC B1805/52, B1806/52, B1807/52 and B1808/52 may be output at this time, but they are not related to this check.

    Result: 

    DTC B1805/52, B1806/52, B1807/52 or B1808/52 is not output 

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

    Result: 

    DTC B1805/52, B1806/52, B1807/52 or B1808/52 is output 

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

  5. CHECK INSTRUMENT PANEL WIRE 
    1. Disconnect the No. 3 instrument panel wire from the instrument panel wire.
      GTY787365Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Instrument Panel Passenger Airbag Assembly
      *2 Airbag ECU Assembly
      *3 No. 3 Instrument Panel Wire
      *4 Instrument Panel Wire
      *a Front view of wire harness connector
      (to No. 3 Instrument Panel Wire)
      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
        PB1-3 (P+) - Body ground Engine switch on (IG) Below 1 V
        PB1-4 (P-) - 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
        PB1-3 (P+) - PB1-4 (P-) 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
        PB1-3 (P+) - Body ground Always 1 MΩ or higher
        PB1-4 (P-) - 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
        PB1-3 (P+) - PB1-4 (P-) 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 NO. 3 INSTRUMENT PANEL WIRE 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL WIRE 

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