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Home >> Toyota >> 2021 >> C-HR LE >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Restraint System - Diagnostic Codes (B1627-B1656) >> Airbag System >> DTC B1653/35: Seat Position Airbag Sensor Circuit Malfunction [02/2017 - 09/2019] >> Procedure

DTC B1653/35: Seat Position Airbag Sensor Circuit Malfunction [02/2017 - 09/2019]: Procedure

  1. CHECK CONNECTORS 
    1. Turn the ignition switch off.
    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 airbag sensor assembly and seat position airbag sensor. Also check that the connectors that link the front No. 2 seat wire LH and floor 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 airbag sensor assembly and seat position airbag sensor. Also disconnect the connectors that link the front No. 2 seat wire LH and floor wire.
    5. Check that the terminals of the connectors are not deformed or damaged.

      OK

      The terminals are not deformed or damaged.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE WIRE HARNESS 

    Result: 

    OK 

    See step  2

  2. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (OPEN) 
    1. Connect the connectors that link the front No. 2 seat wire LH and floor wire.
      GTY748656Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Seat Position Airbag Sensor
      *2 Airbag Sensor Assembly
      *3 Service Wire
      *a Front view of wire harness connector
      (to Airbag Sensor Assembly)
      *b Front view of wire harness connector
      (to Seat Position Airbag Sensor)
    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
      M101-4 (LSP+) - M101-3 (LSP-) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FLOOR WIRE 

    Result: 

    OK 

    See step  3

  3. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT) 
    1. Disconnect the service wire from connector B.
      GTY756107Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Seat Position Airbag Sensor
      *2 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Seat Position Airbag Sensor)
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M101-4 (LSP+) - M101-3 (LSP-) Always 1 MΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FLOOR WIRE 

    Result: 

    OK 

    See step  4

  4. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO B+) 
    1. Connect the cable to the negative (-) battery terminal.
      GTY756107Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Seat Position Airbag Sensor
      *2 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Seat Position Airbag Sensor)
    2. Turn the ignition switch ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      M101-3 (LSP-) - Body ground Ignition switch ON Below 1 V
      M101-4 (LSP+) - Body ground Ignition switch ON Below 1 V
    4. Turn the ignition switch off.
    5. 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.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FLOOR WIRE 

    Result: 

    OK 

    See step  5

  5. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M101-3 (LSP-) - Body ground Always 1 MΩ or higher
      M101-4 (LSP+) - Body ground Always 1 MΩ or higher
      GTY756107Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Seat Position Airbag Sensor
      *2 Airbag Sensor Assembly
      *a Front view of wire harness connector
      (to Seat Position Airbag Sensor)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FLOOR WIRE 

    Result: 

    OK 

    See step  6

  6. CHECK DTC 
    1. Connect the connectors to the airbag sensor assembly and seat position airbag sensor.
      GTY771525Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Seat Position Airbag Sensor
      *2 Airbag Sensor Assembly
    2. Connect the cable to the negative (-) battery terminal.
    3. Clear the DTCs stored in memory.

      Refer to DTC CHECK / CLEAR [02/2017 - 09/2019]

      Body Electrical > SRS Airbag > Clear DTCs 

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

      Refer to DTC CHECK / CLEAR [02/2017 - 09/2019]

      Body Electrical > SRS Airbag > Trouble Codes 

      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.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [02/2017 - 10/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2017 - 05/2018]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [05/2018 - 09/2019] 

    Result: 

    NG 

    See step  7

  7. CHECK SEAT POSITION AIRBAG SENSOR 
    1. Turn the ignition switch off.
      GTY771525Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Seat Position Airbag Sensor
      *2 Airbag Sensor Assembly
    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. Replace the seat position airbag sensor with a known good one.

      Refer to REMOVAL [02/2017 - 09/2019]

      HINT: 

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

    4. Connect the cable to the negative (-) battery terminal.
    5. Clear the DTCs stored in memory.

      Refer to DTC CHECK / CLEAR [02/2017 - 09/2019]

      Body Electrical > SRS Airbag > Clear DTCs 

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

      Refer to DTC CHECK / CLEAR [02/2017 - 09/2019]

      Body Electrical > SRS Airbag > Trouble Codes 

      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 ignition switch off.
    10. 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.

    11. Restore the seat position airbag sensor that was installed for testing to its original location.

      Refer to REMOVAL [02/2017 - 09/2019]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SEAT POSITION AIRBAG SENSOR. Refer to  REMOVAL [02/2017 - 09/2019] 

    Result: 

    NG 

    REPLACE AIRBAG SENSOR ASSEMBLY. Refer to  REMOVAL [02/2017 - 10/2017]  , or refer to  REMOVAL [10/2017 - 09/2019] 

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