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Home >> Lexus >> 2021 >> LC 500 2D Coupe >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (Coupe) (4 Of 5) >> Airbag System >> DTC B1810/53: Short in Driver Side Squib 2nd Step Circuit; DTC B1811/53: Open in Driver Side Squib 2nd Step Circuit; DTC B1812/53: Short to GND in Driver Side Squib 2nd Step Circuit; DTC B1813/53: Short to B+ in Driver Side Squib 2nd Step Circuit [03/2017 - 04/2020] >> Procedure

DTC B1810/53: Short in Driver Side Squib 2nd Step Circuit; DTC B1811/53: Open in Driver Side Squib 2nd Step Circuit; DTC B1812/53: Short to GND in Driver Side Squib 2nd Step Circuit; DTC B1813/53: Short to B+ in Driver Side Squib 2nd Step Circuit [03/2017 - 04/2020]: Procedure

  1. CHECK CONNECTORS 
    1. Turn the engine switch off.
      GTY827639Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly
      *2 Airbag ECU Assembly
      *3 Spiral with Sensor Cable Sub-assembly
      *4 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 horn button assembly, spiral with sensor cable sub-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 horn button assembly, spiral with sensor cable sub-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 spiral with sensor cable sub-assembly connector (on the horn button 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 spiral with sensor cable sub-assembly 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 SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY 

    Result: 

    OK 

    See step  2

  2. CHECK HORN BUTTON ASSEMBLY (DRIVER SIDE SQUIB 2ND STEP) 
    1. Connect the instrument panel wire to the airbag ECU assembly and spiral with sensor cable sub-assembly.
      GTY801709Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly (Driver Side Squib 2nd Step)
      *2 Airbag ECU Assembly
      *3 Spiral with Sensor Cable Sub-assembly
      *4 SST
      *a Front view of wire harness connector
      (to Horn Button Assembly [Driver Side Squib 2nd Step])
      *b Color: Black
    2. Connect the white wire side of SST (resistance: 2.1 Ω) to connector E (black connector).
      WARNING:

      Never connect the tester to the horn button assembly (driver side squib 2nd step) 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 B1810/53, B1811/53, B1812/53 or B1813/53 is not output
      DTC B1810/53, B1811/53, B1812/53 or B1813/53 is output

      HINT: 

      Codes other than DTC B1810/53, B1811/53, B1812/53 and B1813/53 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 B1810/53, B1811/53, B1812/53 or B1813/53 is not output 

    REPLACE HORN BUTTON ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    DTC B1810/53, B1811/53, B1812/53 or B1813/53 is output 

    See step  3

  3. CHECK DRIVER SIDE SQUIB 2ND STEP CIRCUIT 
    1. Disconnect the instrument panel wire from the airbag ECU assembly.
      GTY796037Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly (Driver Side Squib 2nd Step)
      *2 Airbag ECU Assembly
      *3 Spiral with Sensor Cable Sub-assembly
      *a Front view of wire harness connector
      (to Horn Button Assembly [Driver Side Squib 2nd Step])
      *b Color: Black
      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
        z4-2 (D2+) - Body ground Engine switch on (IG) Below 1 V
        z4-1 (D2-) - 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
        z4-2 (D2+) - z4-1 (D2-) 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
        z4-2 (D2+) - Body ground Always 1 MΩ or higher
        z4-1 (D2-) - 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
        z4-2 (D2+) - z4-1 (D2-) 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 horn button assembly (driver side squib 2nd step) and airbag ECU assembly.
      GTY789624Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly (Driver Side Squib 2nd Step)
      *2 Airbag ECU Assembly
      *3 Spiral with Sensor Cable Sub-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 B1810/53, B1811/53, B1812/53 or B1813/53 is not output
      DTC B1810/53, B1811/53, B1812/53 or B1813/53 is output

      HINT: 

      Codes other than DTC B1810/53, B1811/53, B1812/53 and B1813/53 may be output at this time, but they are not related to this check.

    Result: 

    DTC B1810/53, B1811/53, B1812/53 or B1813/53 is not output 

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

    Result: 

    DTC B1810/53, B1811/53, B1812/53 or B1813/53 is output 

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

  5. CHECK INSTRUMENT PANEL WIRE 
    1. Disconnect the instrument panel wire from the spiral with sensor cable sub-assembly.
      GTY785930Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly (Driver Side Squib 2nd Step)
      *2 Airbag ECU Assembly
      *3 Spiral with Sensor Cable Sub-assembly
      *4 Instrument Panel Wire
      *a Front view of wire harness connector
      (to Spiral with Sensor Cable Sub-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
        P18-4 (D2+) - Body ground Engine switch on (IG) Below 1 V
        P18-3 (D2-) - 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
        P18-4 (D2+) - P18-3 (D2-) 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
        P18-4 (D2+) - Body ground Always 1 MΩ or higher
        P18-3 (D2-) - 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
        P18-4 (D2+) - P18-3 (D2-) 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 SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    NG 

    REPLACE INSTRUMENT PANEL WIRE 

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