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Home >> Lexus >> 2011 >> RX 350 FWD >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Supplemental Restraint System (Diagnostic Codes (B1000/31 - B1653/35)) >> 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 engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal.
      NOTE:

      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 center airbag sensor 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 center airbag sensor 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 No. 2 floor wire.
      Fig 1: Front Seat Inner Belt Assembly LH And No. 2 Floor Wire
      GTY356980Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Using SST, connect terminals 9 (LSP+) and 17 (LSP-) of connector B.
      NOTE:

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

      • SST: 09843-18040 
    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 Center Airbag Sensor Assembly
      *3 Front view of wire harness connector
      (to Center Airbag Sensor Assembly)      		 *4 Front view of wire harness connector
      (to Seat Position Airbag Sensor)
      *5 Connector B *6 Connector E

    NG → See step   9 

    OK: Go to next step 

  3. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT) 
    1. Disconnect SST from connector B.
      Fig 2: SST From Connector B
      GTY351372Courtesy 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 Center Airbag Sensor Assembly
      *3 Front view of wire harness connector
      (to Seat Position Airbag Sensor)
      *4 Connector E

    NG → See step   10 

    OK: Go to next step 

  4. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO B+) 
    1. Connect the cable to the negative (-) battery terminal.
      Fig 3: SST From Connector B
      GTY351372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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
      2 (LSP+) - Body ground Engine switch on (IG) Below 1 V
      1 (LSP-) - Body ground Engine switch on (IG) Below 1 V
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Center Airbag Sensor Assembly
      *3 Front view of wire harness connector
      (to Seat Position Airbag Sensor)
      *4 Connector E

    NG → See step   11 

    OK: Go to next step 

  5. CHECK SEAT POSITION AIRBAG SENSOR CIRCUIT (SHORT TO GROUND) 
    1. Turn the engine switch off.
      Fig 4: SST From Connector B
      GTY351372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the cable from the negative (-) battery terminal.
      NOTE:

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

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

      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 Center Airbag Sensor Assembly
      *3 Front view of wire harness connector
      (to Seat Position Airbag Sensor)
      *4 Connector E

    NG → See step   12 

    OK: Go to next step 

  6. CHECK SEAT POSITION AIRBAG SENSOR 
    1. Connect the connectors to the center airbag sensor assembly and seat position airbag sensor.
      Fig 5: Checking Seat Position Sensor
      GTY262340Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect the cable to the negative (-) battery terminal.
    3. Turn the engine 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 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 .

      OK

      DTC B1653/35 is not output.

      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Center Airbag Sensor Assembly

      HINT: 

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

    NG → See step   7 

    OK → See step   13 

  7. REPLACE SEAT POSITION AIRBAG SENSOR 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal.
      NOTE:

      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 part. Refer to REMOVAL .

      HINT: 

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

    NEXT: Go to next step 

  8. CHECK CENTER AIRBAG SENSOR ASSEMBLY 
    1. Connect the cable to the negative (-) battery terminal.
      Fig 6: Checking Seat Position Sensor
      GTY262340Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the engine switch on (IG), and wait for at least 60 seconds.
    3. Clear the DTCs stored in the memory. Refer to DTC CHECK / CLEAR .
    4. Turn the engine switch off.
    5. Turn the engine switch on (IG), and wait for at least 60 seconds.
    6. Check for DTCs. Refer to DTC CHECK / CLEAR .

      OK

      DTC B1653/35 is not output.

      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Center Airbag Sensor Assembly

      HINT: 

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

    NG → See step   14 

    OK → END 

  9. CHECK NO. 2 FLOOR WIRE (OPEN) 
    1. Disconnect the No. 2 floor wire from the front seat inner belt assembly LH.

      HINT: 

      SST has already been inserted into connector B.

      Fig 7: No. 2 Floor Wire From The Front Seat Inner Belt Assembly LH
      GTY349534Courtesy 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
      P7-2 (LSP+) - P7-4 (LSP-) Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor *2 Center Airbag Sensor Assembly
      *3 Front Seat Inner Belt Assembly LH *4 No. 2 Floor Wire
      *5 Front view of wire harness connector
      (to Center Airbag Sensor Assembly)      		 *6 Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)
      *7 Connector B *8 Connector C

    NG → REPLACE NO. 2 FLOOR WIRE 

    OK → See step   15 

  10. CHECK NO. 2 FLOOR WIRE (SHORT) 
    1. Disconnect the No. 2 floor wire from the front seat belt inner belt assembly LH.
      Fig 8: No. 2 Floor Wire From The Front Seat Belt Inner Belt Assembly LH
      GTY359513Courtesy 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
      P7-2 (LSP+) - P7-4 (LSP-) Always 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Center Airbag Sensor Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 No. 2 Floor Wire
      *5 Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)
      *6 Connector C

    NG → REPLACE NO. 2 FLOOR WIRE 

    OK → See step   15 

  11. CHECK NO. 2 FLOOR WIRE (SHORT TO B+) 
    1. Turn the engine switch off.
      Fig 9: No. 2 Floor Wire From The Front Seat Belt Inner Belt Assembly LH
      GTY359513Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the cable from the negative (-) battery terminal.
      NOTE:

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

    3. Disconnect the No. 2 floor wire from the front seat inner belt assembly LH.
    4. Connect the cable to the negative (-) battery terminal.
    5. Turn the engine switch on (IG).
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P7-2 (LSP+) - Body ground Engine switch on (IG) Below 1 V
      P7-4 (LSP-) - Body ground Engine switch on (IG) Below 1 V
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Center Airbag Sensor Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 No. 2 Floor Wire
      *5 Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)
      *6 Connector C

    NG → REPLACE NO. 2 FLOOR WIRE 

    OK → See step   15 

  12. CHECK NO. 2 FLOOR WIRE (SHORT TO GROUND) 
    1. Disconnect the No. 2 floor wire from the front seat inner belt assembly LH.
      Fig 10: No. 2 Floor Wire From The Front Seat Belt Inner Belt Assembly LH
      GTY359513Courtesy 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
      P7-2 (LSP+) - Body ground Always 1 MΩ or higher
      P7-4 (LSP-) - Body ground Always 1 MΩ or higher
      TEXT IN ILLUSTRATION

      *1 Seat Position Airbag Sensor
      *2 Center Airbag Sensor Assembly
      *3 Front Seat Inner Belt Assembly LH
      *4 No. 2 Floor Wire
      *5 Front view of wire harness connector
      (to Front Seat Inner Belt Assembly LH)
      *6 Connector C

    NG → REPLACE NO. 2 FLOOR WIRE 

    OK → See step   15 

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