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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Airbag System - Diagnostic Codes (6 Of 7) >> Airbag System >> DTC B1800: Short in D Squib Circuit; DTC B1801: Open in D Squib Circuit; DTC B1802: Short in D Squib Circuit (to Ground); DTC B1803: Short in D Squib Circuit (to +B) [12/2019 - 11/2023] >> Procedure

DTC B1800: Short in D Squib Circuit; DTC B1801: Open in D Squib Circuit; DTC B1802: Short in D Squib Circuit (to Ground); DTC B1803: Short in D Squib Circuit (to +B) [12/2019 - 11/2023]: Procedure

  1. CHECK CONNECTORS 
    1. Turn the ignition switch off.
      GTY438987Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly
      *2 Spiral Cable Sub-assembly
      *3 Airbag Sensor Assembly
      *4 Instrument Panel 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 horn button assembly, spiral cable sub-assembly 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 horn button assembly, spiral cable sub-assembly 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 spiral cable sub-assembly connector (on the horn button assembly side) is not loose, deformed or damaged.

      OK

      The airbag 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 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 WIRE HARNESS 

    Result: 

    OK 

    See step  2

  2. CHECK HORN BUTTON ASSEMBLY 
    1. Connect the instrument panel wire to the airbag sensor assembly and spiral cable sub-assembly.
      GTY894266Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly
      *2 Spiral Cable Sub-assembly
      *3 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Horn Button Assembly)
      *b Color: Light Green
    2. Connect SST (resistance 2.1 Ω) to connector E (light green connector).
      WARNING:

      Never connect a tester to the horn button 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 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 ignition switch to ON, and wait for at least 60 seconds.
    5. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    6. Turn the ignition switch off.
    7. Turn the ignition switch to ON, and wait for at least 60 seconds.
    8. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1800, B1801, B1802 or B1803 is not output.

      HINT: 

      Codes other than DTCs B1800, B1801, B1802 and B1803 may be output at this time, but they are not related to this check.

    9. Turn the ignition 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 HORN BUTTON ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    See step  3

  3. CHECK DRIVER SQUIB CIRCUIT 
    1. Disconnect the instrument panel wire from the airbag sensor assembly.
      GTY942079Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly
      *2 Spiral Cable Sub-assembly
      *3 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Horn Button Assembly)
      *b Color: Light Green
    2. Check for a short to B+ in the circuit.
      1. Connect the cable to the negative (-) auxiliary battery terminal.
      2. Turn the ignition switch to ON.
      3. Measure the voltage according to the value(s) in the table below.

        Standard Voltage

        Tester Connection Condition Specified Condition
        z2-2 (D+) - Body ground Ignition switch ON Below 1 V
        z2-1 (D-) - Body ground Ignition switch ON Below 1 V
      4. Turn the ignition 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
        z2-2 (D+) - z2-1 (D-) 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
        z2-2 (D+) - Body ground Always 1 MΩ or higher
        z2-1 (D-) - 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 [12/2019 - 10/2021] , or refer to SYSTEM DESCRIPTION [10/2021 - 11/2023]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        z2-2 (D+) - z2-1 (D-) 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 and airbag sensor assembly.
      GTY447904Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly
      *2 Spiral Cable Sub-assembly
      *3 Airbag Sensor Assembly
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Turn the ignition switch to ON, and wait for at least 60 seconds.
    4. Clear the DTCs stored in memory.

      Body Electrical > SRS Airbag > Clear DTCs 

    5. Turn the ignition switch off.
    6. Turn the ignition switch to ON, and wait for at least 60 seconds.
    7. Check for DTCs.

      Body Electrical > SRS Airbag > Trouble Codes 

      OK

      DTC B1800, B1801, B1802 or B1803 is not output.

      HINT: 

      Codes other than DTCs B1800, B1801, B1802 and B1803 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 [12/2019 - ] 

    Result: 

    NG 

    REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

  5. CHECK INSTRUMENT PANEL WIRE 
    1. Disconnect the instrument panel wire from the spiral cable sub-assembly.
      GTY910544Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly
      *2 Spiral Cable Sub-assembly
      *3 Airbag Sensor Assembly
      *4 Instrument Panel Wire
      *a Front view of wire harness connector
      (to Spiral Cable Sub-assembly)
    2. Check for a short to B+ in the circuit.
      1. Connect the cable to the negative (-) auxiliary battery terminal.
      2. Turn the ignition switch to ON.
      3. Measure the voltage according to the value(s) in the table below.

        Standard Voltage

        Tester Connection Condition Specified Condition
        H25-1 (D+) - Body ground Ignition switch ON Below 1 V
        H25-2 (D-) - Body ground Ignition switch ON Below 1 V
      4. Turn the ignition 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
        H25-1 (D+) - H25-2 (D-) 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
        H25-1 (D+) - Body ground Always 1 MΩ or higher
        H25-2 (D-) - 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 [12/2019 - 10/2021] , or refer to SYSTEM DESCRIPTION [10/2021 - 11/2023]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        H25-1 (D+) - H25-2 (D-) 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  6

  6. CHECK SPIRAL CABLE SUB-ASSEMBLY 
    1. Check for a short to B+ in the circuit.
      GTY904810Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Horn Button Assembly
      *2 Spiral Cable Sub-assembly
      *3 Airbag Sensor Assembly
      *4 Instrument Panel Wire
      *a Front view of wire harness connector
      (to Horn Button Assembly)
      *b Color: Light Green
      1. Connect the cable to the negative (-) auxiliary battery terminal.
      2. Turn the ignition switch to ON.
      3. Measure the voltage according to the value(s) in the table below.

        Standard Voltage

        Tester Connection Condition Specified Condition
        z2-2 (D+) - Body ground Ignition switch ON Below 1 V
        z2-1 (D-) - Body ground Ignition switch ON Below 1 V
      4. Turn the ignition 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
        z2-2 (D+) - z2-1 (D-) 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
        z2-2 (D+) - Body ground Always 1 MΩ or higher
        z2-1 (D-) - 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 SYSTEM DESCRIPTION [12/2019 - 10/2021] , or refer to SYSTEM DESCRIPTION [10/2021 - 11/2023]

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

        Standard Resistance

        Tester Connection Condition Specified Condition
        z2-2 (D+) - z2-1 (D-) 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 [12/2019 - ] 

    Result: 

    NG 

    REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

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