LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2021 >> RC F Base >> Repair and Diagnosis >> Body & Frame >> Seats >> Front Power Seat Control System - Diagnostic Codes & Symptom Tests >> Front Power Seat Control System >> One-touch Walk-in Function does not Operate [09/2014 - ] >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

One-touch Walk-in Function does not Operate [09/2014 - ]: Procedure

  1. CHECK FRONT POWER SEAT OPERATION 
    1. Check that each function of the power seat operates normally by using the position control ECU and switch assembly LH or position control ECU and switch assembly RH.

      Refer to OPERATION CHECK [09/2014 - 11/2017] , or refer to OPERATION CHECK [11/2017 - ]

      Result

      Result Proceed to
      Driver power seat functions do not operate A
      Front passenger power seat functions do not operate B

    Result: 

    See step  11

    Result: 

    See step  2

  2. CHECK SEAT BELT TENSION REDUCER SYSTEM 
    1. Check the seat belt tension reducer system.

      Refer to SYSTEM DESCRIPTION [09/2014 - ]

      OK

      Seat belt tension reducer system is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO SEAT BELT TENSION REDUCER SYSTEM. Refer to  PROBLEM SYMPTOMS TABLE [09/2014 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK FOR DTC 
    1. Perform "DTC Output Confirmation Operation" procedure.
    2. Check for DTCs.

      Powertrain > Engine > Trouble Codes 

      OK

      P0705 is not output.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO SFI SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2014 - ] 

    Result: 

    OK 

    See step  4

  4. READ VALUE USING TECHSTREAM (SHIFT P POSITION STATE) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Driver Seat / Data List.
    5. Read the Data List according to the display on the Techstream.

      Body Electrical > Driver Seat > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Shift SW Position Park state signal Shift P or Shift Other Shift P: Shift lever in P
      Shift Other: Shift lever in a position other than P
      -

      Body Electrical > Driver Seat > Data List 

      Tester Display
      Shift SW Position

      OK

      The Techstream display changes correctly in response to the shift lever position.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY LH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  5

  5. READ VALUE USING TECHSTREAM (OPERATION LEVER STATE AND SLIDE FRONT OPERATION PERMITTED) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Driver Seat / Data List.
    5. Read the Data List according to the display on the Techstream.

      Body Electrical > Driver Seat > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Operation Lever State Reclining remote control lever sub-assembly state Lock or Unlock Lock: Reclining remote control lever sub-assembly locked
      Unlock: Reclining remote control lever sub-assembly unlocked
      -
      Slide Front Operation Permitted Forward operation permission state NO or YES NO: Not permitted
      YES: Permitted
      -

      Body Electrical > Driver Seat > Data List 

      Tester Display
      Operation Lever State
      Slide Front Operation Permitted

      Result

      Result Proceed to
      The value of each Data List item change accordingly. A
      The value of the Data List item "Operation Lever State" does not change according to the operation of the reclining remote control lever sub-assembly. B
      The value of the Data List item "Slide Front Operation Permitted" does not change according to the forward operation permission state. C
      The value of each Data List item does not change. D

    Result: 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2014 - 08/2016]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - 11/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2017 - 03/2019]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2019 - 09/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2020 - 01/2023]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [01/2023 - ] 

    Result: 

    See step  8

    Result: 

    See step  10

    Result: 

    See step  6

  6. INSPECT INNER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (DRIVER SEAT)) 
    1. Remove the inner limit switch assembly (front seatback edge protector (driver seat)).

      Refer to REMOVAL [09/2014 - ]

    2. Inspect the inner limit switch assembly (front seatback edge protector (driver seat)).

      Refer to INSPECTION [09/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE INNER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (DRIVER SEAT)). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY LH - INNER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR DRIVER SEAT (DRIVER))) 
    1. Disconnect the b5 position control ECU and switch assembly LH connector.
    2. Disconnect the d4 inner limit switch assembly (front seatback edge protector (driver seat)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      b5-6 (SWS2) - d4-1 Always Below 1 Ω
      b5-6 (SWS2) or d4-1 - Body ground Always 10 kΩ or higher
      b5-1 (SGND) - d4-2 Always Below 1 Ω
      b5-1 (SGND) or d4-2 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY LH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  8. INSPECT OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (DRIVER SEAT)) 
    1. Remove the outer limit switch assembly (front seatback edge protector (driver seat)).

      Refer to REMOVAL [09/2014 - ]

    2. Inspect the outer limit switch assembly (front seatback edge protector (driver seat)).

      Refer to INSPECTION [09/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (DRIVER SEAT)). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY LH - OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (DRIVER SEAT))) 
    1. Disconnect the b5 position control ECU and switch assembly LH connector.
    2. Disconnect the b10 outer limit switch assembly (front seatback edge protector (driver seat)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      b5-2 (SWS1) - b10-1 Always Below 1 Ω
      b5-2 (SWS1) or b10-1 - Body ground Always 10 kΩ or higher
      b5-1 (SGND) - b10-2 Always Below 1 Ω
      b5-1 (SGND) or b10-2 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY LH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  10. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY LH - OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (DRIVER SEAT))) 
    1. Disconnect the b5 position control ECU and switch assembly LH connector.
    2. Disconnect the b10 outer limit switch assembly (front seatback edge protector (driver seat)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      b5-1 (SGND) - b10-2 Always Below 1 Ω
      b5-1 (SGND) or b10-2 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY LH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. READ VALUE USING TECHSTREAM (P SEAT BUCKLE SWITCH) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Passenger Seat / Data List.
    5. Read the Data List according to the display on the Techstream.

      Body Electrical > Passenger Seat > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      P Seat Buckle Switch Front passenger seat belt buckle switch ON or OFF ON: Front passenger seat belt fastened
      OFF: Front passenger seat belt unfastened
      -

      Body Electrical > Passenger Seat > Data List 

      Tester Display
      P Seat Buckle Switch

      OK

      On the Techstream screen, ON or OFF is displayed accordingly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  23

    Result: 

    OK 

    See step  12

  12. READ VALUE USING TECHSTREAM (OCCUPANT SENSOR) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Passenger Seat / Data List.
    5. Read the Data List according to the display on the Techstream.

      Body Electrical > Passenger Seat > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Occupant Sensor Occupant sensor condition ON or OFF ON: Occupant Sensor on
      OFF: Occupant Sensor off
      -

      Body Electrical > Passenger Seat > Data List 

      Tester Display
      Occupant Sensor

      OK

      On the Techstream screen, ON or OFF is displayed accordingly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  21

    Result: 

    OK 

    See step  13

  13. CHECK FOR DTC 
    1. Perform "DTC Output Confirmation Operation" procedure.
    2. Check for DTCs.

      Powertrain > Engine > Trouble Codes 

      OK

      P0705 is not output.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO SFI SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2014 - ] 

    Result: 

    OK 

    See step  14

  14. READ VALUE USING TECHSTREAM (SHIFT P POSITION STATE) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Passenger Seat / Data List.
    5. Read the Data List according to the display on the Techstream.

      Body Electrical > Passenger Seat > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Shift SW Position Park state signal Shift P or Shift Other Shift P: Shift lever in P
      Shift Other: Shift lever in a position other than P
      -

      Body Electrical > Passenger Seat > Data List 

      Tester Display
      Shift SW Position

      OK

      The Techstream display changes correctly in response to the shift lever position.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  15

  15. READ VALUE USING TECHSTREAM (OPERATION LEVER STATE AND SLIDE FRONT OPERATION PERMITTED) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Passenger Seat / Data List.
    5. Read the Data List according to the display on the Techstream.

      Body Electrical > Passenger Seat > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Operation Lever State Reclining remote control lever sub-assembly state Lock or Unlock Lock: Reclining remote control lever sub-assembly locked
      Unlock: Reclining remote control lever sub-assembly unlocked
      -
      Slide Front Operation Permitted Forward operation permission state NO or YES NO: Not permitted
      YES: Permitted
      -

      Body Electrical > Passenger Seat > Data List 

      Tester Display
      Operation Lever State
      Slide Front Operation Permitted

      Result

      Result Proceed to
      The value of each Data List item change accordingly. A
      The value of the Data List item "Operation Lever State" does not change according to the operation of the reclining remote control lever sub-assembly. B
      The value of the Data List item "Slide Front Operation Permitted" does not change according to the forward operation permission state. C
      The value of each Data List item does not change. D

    Result: 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2014 - 08/2016]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2016 - 11/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2017 - 03/2019]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2019 - 09/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2020 - 01/2023]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [01/2023 - ] 

    Result: 

    See step  18

    Result: 

    See step  20

    Result: 

    See step  16

  16. INSPECT INNER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (FRONT PASSENGER SEAT)) 
    1. Remove the inner limit switch assembly (front seatback edge protector (front passenger seat)).

      Refer to REMOVAL [09/2014 - ]

    2. Inspect the inner limit switch assembly (front seatback edge protector (front passenger seat)).

      Refer to INSPECTION [09/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE INNER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (FRONT PASSENGER SEAT)). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  17

  17. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY RH - INNER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (FRONT PASSENGER SEAT)) 
    1. Disconnect the a5 position control ECU and switch assembly RH connector.
    2. Disconnect the c3 inner limit switch assembly (front seatback edge protector (front passenger seat)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      a5-6 (ELS2) - c3-1 Always Below 1 Ω
      a5-6 (ELS2) or c3-1 - Body ground Always 10 kΩ or higher
      a5-1 (SGND) - c3-2 Always Below 1 Ω
      a5-1 (SGND) or c3-2 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  18. INSPECT OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (FRONT PASSENGER SEAT)) 
    1. Remove the outer limit switch assembly (front seatback edge protector).

      Refer to REMOVAL [09/2014 - ]

    2. Inspect the outer limit switch assembly (front seatback edge protector).

      Refer to INSPECTION [09/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  19

  19. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY RH - OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (FRONT PASSENGER SEAT)) 
    1. Disconnect the a5 position control ECU and switch assembly RH connector.
    2. Disconnect the a9 outer limit switch assembly (front seatback edge protector (front passenger seat)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      a5-2 (ELS1) - a9-1 Always Below 1 Ω
      a5-2 (ELS1) or a9-1 - Body ground Always 10 kΩ or higher
      a5-1 (SGND) - a9-2 Always Below 1 Ω
      a5-1 (SGND) or a9-2 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  20. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY RH - OUTER LIMIT SWITCH ASSEMBLY (FRONT SEATBACK EDGE PROTECTOR (FRONT PASSENGER SEAT)) 
    1. Disconnect the a5 position control ECU and switch assembly RH connector.
    2. Disconnect the a9 outer limit switch assembly (front seatback edge protector (front passenger seat)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      a5-1 (SGND) - a9-2 Always Below 1 Ω
      a5-1 (SGND) or a9-2 - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  21. INSPECT OCCUPANT DETECTION SENSOR (FRONT SEAT CUSHION PAD WITH COVER (FRONT PASSENGER SEAT)) 
    1. Remove the occupant detection sensor (front seat cushion pad with cover (front passenger seat)).

      Refer to REMOVAL [09/2014 - ]

    2. Inspect the occupant detection sensor (front seat cushion pad with cover (front passenger seat)).

      Refer to INSPECTION [09/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE OCCUPANT DETECTION SENSOR (FRONT SEAT CUSHION PAD WITH COVER (FRONT PASSENGER SEAT)). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  22

  22. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY RH - OCCUPANT DETECTION SENSOR (FRONT SEAT CUSHION PAD WITH COVER (FRONT PASSENGER SEAT) - BODY GROUND) 
    1. Disconnect the a5 position control ECU and switch assembly RH connector.
    2. Disconnect the a10 occupant detection sensor (front seat cushion pad with cover (front passenger seat)) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      a5-9 (SSRC) - a10-3 Always Below 1 Ω
      a5-9 (SSRC) or a10-3 - Body ground Always 10 kΩ or higher
      a10-1 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  23. INSPECT FRONT SEAT INNER BELT ASSEMBLY RH 
    1. Remove the front seat inner belt assembly RH.

      Refer to REMOVAL [09/2014 - ]

    2. Inspect the front seat inner belt assembly RH (seat belt warning switch).

      Refer to INSPECTION [09/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE FRONT SEAT INNER BELT ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  24

  24. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH ASSEMBLY RH - FRONT SEAT INNER BELT ASSEMBLY RH - BODY GROUND) 
    1. Disconnect the a5 position control ECU and switch assembly RH connector.
    2. Disconnect the a8 front seat inner belt assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      a5-10 (PBCL) - a8-1 Always Below 1 Ω
      a5-10 (PBCL) or a8-1 - Body ground Always 10 kΩ or higher
      a8-2 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR