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Home >> Scion >> 2013 >> iQ EV >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Restraint System (Diagnostic Codes B1693/81 - B1907/74 & Symptom Tests) (Electric) >> Airbag System >> DTC B1870/66: Short in Driver Side Front Seat Cushion Squib Circuit; DTC B1871/66: Open in Driver Side Front Seat Cushion Squib Circuit; DTC B1872/66: Short to GND in Driver Side Front Seat Cushion Squib Circuit; DTC B1873/66: Short to B+ in Driver Side Front Seat Cushion Squib Circuit >> Procedure

DTC B1870/66: Short in Driver Side Front Seat Cushion Squib Circuit; DTC B1871/66: Open in Driver Side Front Seat Cushion Squib Circuit; DTC B1872/66: Short to GND in Driver Side Front Seat Cushion Squib Circuit; DTC B1873/66: Short to B+ in Driver Side Front Seat Cushion Squib Circuit: Procedure

  1. CHECK CONNECTORS 
    1. Turn the power switch off.
      Fig 1: Identifying Front Seat Airbag Sub-Assembly LH, Airbag ECU Assembly & Floor Wire Circuit
      GTY386296Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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 connector is properly connected to the front seat airbag sub-assembly LH.

      OK

      The connector is properly connected.

      HINT: 

      If the connector is not connected securely, reconnect the connector and proceed to the next inspection.

    4. Disconnect the connector from the front seat airbag sub-assembly LH.
    5. Check that the terminal of the connector is not damaged.

      OK

      The terminal is not deformed or damaged.

    6. Check that the floor wire connector (on the front seat airbag sub-assembly LH side) is not damaged.

      OK

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

    7. Check that the short spring for the floor wire with the activation prevention mechanism is not deformed or damaged.

      OK

      The short spring is not deformed or damaged.

      *1 Front Seat Airbag Sub-assembly LH
      *2 Airbag ECU Assembly
      *3 Floor wire

    NG → REPLACE FLOOR WIRE 

    OK: Go to next step 

  2. CHECK FRONT SEAT AIRBAG SUB-ASSEMBLY LH (SEAT CUSHION SQUIB LH) 
    • SST: 09843-18061 
    Fig 2: Identifying Front Seat Airbag Sub-assembly LH Connector Terminals
    GTY386551Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Connect the connector to the airbag ECU assembly.
    2. Connect SST (resistance: 2.1 Ω) to connector C.
      WARNING:

      Never connect the tester to the front seat airbag sub-assembly LH (seat cushion squib 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.
    3. Connect the cable to the negative (-) auxiliary battery terminal.
    4. Turn the power switch on (IG), and wait for at least 60 seconds.
    5. Clear the DTCs stored in the memory. Refer to DTC CHECK / CLEAR .
    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 .

      OK

      DTC B1870/66, B1871/66, B1872/66 or B1873/66 is not output.

      HINT: 

      DTCs other than B1870/66, B1871/66, B1872/66 and B1873/66 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.
      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 C.
      TEXT IN ILLUSTRATION

      *1 Front Seat Airbag Sub-assembly LH
      *2 Airbag ECU Assembly
      *a Front view of wire harness connector
      (to Front Seat Airbag Sub-assembly LH)

    NG → See step   3 

    OK → See step   5 

  3. CHECK FLOOR WIRE 
    Fig 3: Measuring Voltage Of Front Seat Airbag Sub-Assembly LH Connector
    GTY385877Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the floor wire from the airbag ECU assembly.
    2. Check for a short to B+ in the circuit.
      1. Connect the cable to the negative (-) auxiliary battery terminal.
      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
        G30-2 (FCD+) - Body ground Power switch on (IG) Below 1 V
        G30-1 (FCD-) - 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.
        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
        G30-2 (FCD+) - G30-1 (FCD-) 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
        G30-2 (FCD+) - Body ground Always 1 MΩ or higher
        G30-1 (FCD-) - 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 DIAGNOSIS SYSTEM .
      2. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        G30-2 (FCD+) - G30-1 (FCD-) Always 1 MΩ or higher
    6. Restore the released activation prevention mechanism of connector B to the original condition.
      TEXT IN ILLUSTRATION

      *1 Front Seat Airbag Sub-assembly LH
      *2 Airbag ECU Assembly
      *3 Floor Wire
      *a Front view of wire harness connector
      (to Front Seat Airbag Sub-assembly LH)

    NG → REPLACE FLOOR WIRE 

    OK: Go to next step 

  4. CHECK DTC 
    1. Connect the connectors to the front seat airbag sub-assembly LH and the airbag ECU assembly.
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Turn the power switch on (IG), and wait for at least 60 seconds.
    4. Clear the DTCs stored in the memory. Refer to DTC CHECK / CLEAR .
    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 .

      OK

      DTC B1870/66, B1871/66, B1872/66 or B1873/66 is not output.

      HINT: 

      DTCs other than B1870/66, B1871/66, B1872/66 and B1873/66 may be output at this time, but they are not related to this check.

    NG → See step   6 

    OK → See step   7 

  5. REPLACE FRONT SEAT AIRBAG SUB-ASSEMBLY LH. Refer to  REMOVAL 
  6. REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL 
  7. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
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