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Home >> Scion >> 2013 >> iQ EV >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Restraint System (Diagnostic Codes B1000/31 - B1690/15) (Electric) >> Airbag System >> DTC B1653/35: Seat Position Airbag Sensor Circuit Malfunction >> Procedure

DTC B1653/35: Seat Position Airbag Sensor Circuit Malfunction: Procedure

  1. CHECK CONNECTORS 
    1. Turn the power switch off.
    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 airbag ECU assembly, front seat inner belt assembly LH and seat position airbag sensor.

      OK

      The connectors are properly connected.

      HINT: 

      If the connectors are not connected securely, reconnect the connectors and proceed to the next inspection.

    4. Disconnect the connectors from the airbag ECU assembly, front seat inner belt assembly LH and seat position airbag sensor.
    5. Check that the terminals of connectors are not damaged.

      OK

      The terminals are not deformed or damaged.

    NG → REPLACE WIRE HARNESS 

    OK: Go to next step 

  2. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (OPEN) 
    1. Connect the connectors to the front seat inner belt assembly LH and floor wire.
      Fig 1: Measuring Resistance Of Airbag ECU Assembly & Seat Position Airbag Sensor Connectors
      GTY390604Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Using a service wire, connect terminals 9 (LSP+) and 17 (LSP-) of connector B.
      NOTE:

      Do not forcibly insert the service wire into the terminals of the connector when connecting the wire.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (LSP+) - 1 (LSP-) Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *3 Service Wire
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Seat Position Airbag Sensor)

    NG → See step   8 

    OK: Go to next step 

  3. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT) 
    1. Disconnect the service wire from connector B.
      Fig 2: Measuring Resistance Of Seat Position Airbag Sensor Connector
      GTY391247Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (LSP+) - 1 (LSP-) Always 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *a Front view of wire harness connector
      (to Seat Position Airbag Sensor)

    NG → See step   9 

    OK: Go to next step 

  4. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO B+) 
    1. Connect the cable to the negative (-) auxiliary battery terminal.
      Fig 3: Measuring Voltage Of Seat Position Airbag Sensor Connector
      GTY391247Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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
      2 (LSP+) - Body ground Power switch on (IG) Below 1 V
      1 (LSP-) - 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.

      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *a Front view of wire harness connector
      (to Seat Position Airbag Sensor)

    NG → See step   10 

    OK: Go to next step 

  5. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO GROUND) 
    1. Measure the resistance according to the value(s) in the table below.
      Fig 4: Measuring Resistance Of Seat Position Airbag Sensor Connector
      GTY391247Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (LSP+) - Body ground Always 1 MΩ or higher
      1 (LSP-) - Body ground Always 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *a Front view of wire harness connector
      (to Seat Position Airbag Sensor)

    NG → See step   11 

    OK: Go to next step 

  6. CHECK DTC 
    1. Connect the connectors to the airbag ECU assembly and seat position airbag sensor.
      Fig 5: Identifying Airbag ECU Assembly & Seat Position Airbag Sensor Circuit
      GTY390820Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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 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 B1653/35 is not output.

      HINT: 

      Codes other than DTC B1653/35 may be output at this time, but they are not related to this check.

    8. Turn the power switch off.
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly

    NG → See step   7 

    OK → See step   12 

  7. REPLACE SEAT POSITION AIRBAG SENSOR 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
      Fig 6: Identifying Airbag ECU Assembly & Seat Position Airbag Sensor Circuit
      GTY390820Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      WARNING:

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

    2. Replace the seat position airbag sensor with a known good one. Refer to REMOVAL .

      HINT: 

      Perform the following inspection using known good parts from another vehicle if possible.

    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 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 B1653/35 is not output.

      HINT: 

      Codes other than DTC B1653/35 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.
    11. Return the seat position airbag sensor that was installed for testing to its original location. Refer to REMOVAL .
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly

    NG → See step   13 

    OK → END (SEAT POSITION AIRBAG SENSOR WAS DEFECTIVE) 

  8. CHECK FLOOR WIRE (OPEN) 
    1. Disconnect the floor wire from the front seat inner belt assembly LH.
      Fig 7: Measuring Resistance Of Airbag ECU Assembly & Front Seat Inner Belt Assembly LH Connectors
      GTY391034Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT: 

      The service wire has already been inserted into connector B.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      G8-4 (LSP+) - G8-3 (LSP-) Always Below 1 Ω
    3. Disconnect the service wire from the connector B.
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 Floor Wire
      *5 Service Wire
      *a Front view of wire harness connector
      (to Airbag ECU Assembly)
      *b Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)

    NG → REPLACE FLOOR WIRE 

    OK → See step   14 

  9. CHECK FLOOR WIRE (SHORT) 
    1. Disconnect the floor wire from the front seat inner belt assembly LH.
      Fig 8: Measuring Resistance Of Front Seat Inner Belt Assembly LH Connector
      GTY391372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G8-4 (LSP+) - G8-3 (LSP-) Always 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 Floor Wire
      *a Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)

    NG → REPLACE FLOOR WIRE 

    OK → See step   14 

  10. CHECK FLOOR WIRE (SHORT TO B+) 
    1. Disconnect the floor wire from the front seat inner belt assembly LH.
      Fig 9: Measuring Voltage Of Front Seat Inner Belt Assembly LH Connector
      GTY391372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect the cable to the negative (-) auxiliary battery terminal.
    3. Turn the power switch on (IG).
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      G8-4 (LSP+) - Body ground Power switch on (IG) Below 1 V
      G8-3 (LSP-) - Body ground Power switch on (IG) Below 1 V
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 Floor Wire
      *a Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)

    NG → REPLACE FLOOR WIRE 

    OK → See step   14 

  11. CHECK FLOOR WIRE (SHORT TO GROUND) 
    1. Disconnect the floor wire from the front seat inner belt assembly LH.
      Fig 10: Measuring Resistance Of Front Seat Inner Belt Assembly LH Connector
      GTY391372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G8-4 (LSP+) - Body ground Always 1 MΩ or higher
      G8-3 (LSP-) - Body ground Always 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Airbag ECU Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 Floor Wire
      *a Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)

    NG → REPLACE FLOOR WIRE 

    OK → See step   14 

  12. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  13. REPLACE AIRBAG ECU ASSEMBLY. Refer to  REMOVAL 
  14. REPLACE FRONT SEAT INNER BELT ASSEMBLY LH. Refer to  REMOVAL 
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