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Home >> Lexus >> 2008 >> LS 460L >> Repair and Diagnosis >> Body & Frame >> Seats >> Rear Power Seat Control System >> DTC B2654 Headrest Sensor Malfunction >> Inspection Procedure

Inspection Procedure

  1. CHECK FOR DTC 
    1. DTC output area check
      1. Using the Techstream, determine the area that output the DTC.

        Result 

        RESULT CHART

        Result Proceed to
        B2654 output from rear left seat ECU A
        B2654 output from rear right seat ECU B

    B: Go to step  9

    A: Go to Next Step 

  2. PERFORM ACTIVE TEST BY TECHSTREAM (POWER SEAT MOTOR FUNCTION) 
    1. Select the Active Test, use the Techstream to generate a control command, and then check the power seat motor function.

      Rear Left Seat 

      REAR LEFT SEAT ACTIVE TEST REFERENCE CHART

      Tester Display Test Part Control Range
      Headrest Operation Seat headrest operation UP/DOWN

      OK: Motor operates normally. 

    NG: Go to step  7

    OK: Go to Next Step 

  3. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU LH - REAR HEADREST MOTOR LH AND BODY GROUND) 
    1. Disconnect the f25 ECU connector.
    2. Disconnect the f26 motor connector.
    3. Measure the resistance according to the values in the table below.

      Standard Resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      f25-4 (PVCC) - f26-4 (PVCC) Always Below 1 Ω
      f25-3 (SSRH) - f26-2 (SSRV) Always Below 1 Ω
      f25-12 (SGND) - f26-3 (GND) Always Below 1 Ω
      f25-4 (PVCC) - Body ground Always 10 kΩ or higher
      f25-3 (SSRH) - Body ground Always 10 kΩ or higher
      f25-12 (SGND) - Body ground Always 10 kΩ or higher
      Fig 1: Identifying f25 ECU And f26 Motor Connector Terminals
      G05856141Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  4. CHECK REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY (POSITION CONTROL SENSOR) 
    1. Disconnect the f.26 motor connector.
    2. Measure the voltage according to the values in the table below.

      Standard Voltage 

      VOLTAGE SPECIFIED CONDITIONS

      Tester Connection Switch Condition Specified Condition
      f26-4 (PVCC) - f26-3 (GND) Headrest switch signal ON 7.2 to 8.8 V
      Fig 2: Identifying f26 Motor Connector Terminals
      G04952534Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE POSITION CONTROL ECU LH  (See DISASSEMBLY  )

    OK: Go to Next Step 

  5. CHECK REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY (POSITION CONTROL SENSOR) 
    1. Reconnect the f.26 motor connector.
    2. Measure the voltage according to the value in the table below.

      Standard Voltage 

      VOLTAGE SPECIFIED CONDITIONS

      Tester Connection Switch Condition Specified Condition
      f26-2 (SSRV) - Body ground Headrest switch signal ON 0 to 8V
      Fig 3: Identifying f26 Motor Connector Terminals
      G04954166Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY  (See DISASSEMBLY  )

    OK: Go to Next Step 

  6. CHECK FOR DTC 
    1. Clear the DTC (see DTC CHECK / CLEAR  ).
    2. Recheck the DTC.

      OK: DTC B2654 is not output. 

    NG: REPLACE POSITION CONTROL ECU LH  (See DISASSEMBLY  )

    OK: END (SYSTEM RETURN TO NORMAL) 

  7. CHECK REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY (POWER SEAT MOTOR) 
    1. Check operation of the power seat motor (headrest motor).
    2. Check if the seat headrest adjuster moves smoothly when the battery is connected to the headrest motor connector terminals.

      OK 

      HEADREST MOTOR OPERATION CHART

      Measurement Condition Operational Direction
      Battery positive (+) → 5
      Battery negative (-) → 1      		 Upward
      Battery positive (+) → 1
      Battery negative (-) → 5      		 Downward
      Fig 4: Identifying Power Seat Motor Connector Terminals
      G04952536Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY  (See DISASSEMBLY  )

    OK: Go to Next Step 

  8. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU LH - REAR HEADREST MOTOR LH) 
    1. Disconnect the f24 ECU connector.
    2. Disconnect the f26 motor connector.
    3. Measure the resistance according to the values in the table below.

      Standard Resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      f24-5 (HUP) - f26-5 Always Below 1 Ω
      f24-1 (HDWN) - f26-1 Always Below 1 Ω
      Fig 5: Identifying f24 ECU And f26 Motor Connector Terminals
      G05856145Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE POSITION CONTROL ECU LH  (See DISASSEMBLY  )

  9. PERFORM ACTIVE TEST BY TECHSTREAM (POWER SEAT MOTOR FUNCTION) 
    1. Select the Active Test, use the Techstream to generate a control command, and then check the power seat motor function.

      Rear Right Seat 

      REAR RIGHT SEAT ACTIVE TEST REFERENCE CHART

      Tester Display Test Part Control Range
      Headrest Operation Seat headrest operation UP/DOWN

      OK: Motor operates normally. 

    NG: Go to step  14

    OK: Go to Next Step 

  10. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU RH - REAR HEADREST MOTOR RH AND BODY GROUND) 
    1. Disconnect the f5 ECU connector.
    2. Disconnect the f6 motor connector.
    3. Measure the resistance according to the values in the table below.

      Standard Resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      f5-4 (PVCC) - f6-4 (PVCC) Always Below 1 Ω
      f5-3 (SSRH) - f6-2 (SSRV) Always Below 1 Ω
      f5-12 (SGND) - f6-3 (GND) Always Below 1 Ω
      f5-4 (PVCC) - Body ground Always 10 kΩ or higher
      f5-3 (SSRH) - Body ground Always 10 kΩ or higher
      f5-12 (SGND) - Body ground Always 10 kΩ or higher
      Fig 6: Identifying f5 ECU And f6 Motor Connector Terminals
      G04952538Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  11. CHECK REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY (POSITION CONTROL SENSOR) 
    1. Disconnect the f6 motor connector.
    2. Measure the voltage according to the values in the table below.

      Standard Voltage 

      VOLTAGE SPECIFIED CONDITIONS

      Tester Connection Switch Condition Specified Condition
      f6-4 (PVCC) -f6-3 (GND) Headrest switch signal ON 7.2 to 8.8 V

      Result 

      RESULT CHART

      Result Proceed to
      OK A
      NG (w/o Ottoman) B
      NG (w/ Ottoman) C
      Fig 7: Identifying f6 Motor Connector Terminals
      G04952539Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    B: REPLACE POSITION CONTROL ECU RH  (See DISASSEMBLY  )

    C: REPLACE POSITION CONTROL ECU RH  (See DISASSEMBLY  )

    A: Go to Next Step 

  12. CHECK REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY (POSITION CONTROL SENSOR) 
    1. Reconnect the f6 motor connector.
    2. Measure the voltage according to the value in the table below.

      Standard Voltage 

      VOLTAGE SPECIFIED CONDITIONS

      Tester Connection Switch Condition Specified Condition
      f6-2 (SSRV) - Body ground Headrest switch signal ON 0 to 8V
      Fig 8: Identifying f6 Motor Connector Terminals
      G05856148Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY  (See DISASSEMBLY  )

    OK: Go to Next Step 

  13. CHECK FOR DTC 
    1. Clear the DTC (see DTC CHECK / CLEAR  ).
    2. Recheck the DTC.

      OK: DTC B2654 is not output. 

      Result 

      DTC OUTPUT RESULT

      Result Proceed to
      DTC B2654 is not output A
      DTC B2654 is output (w/o Ottoman) B
      DTC B2654 is output (w/ Ottoman) C

    B: REPLACE POSITION CONTROL ECU RH  (See DISASSEMBLY  )

    C: REPLACE POSITION CONTROL ECU RH  (See DISASSEMBLY  )

    A: END (SYSTEM RETURN TO NORMAL) 

  14. CHECK REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY (POWER SEAT MOTOR) 
    1. Check operation of the power seat motor (headrest motor).
    2. Check if the seat headrest adjuster moves smoothly when the battery is connected to the headrest motor connector terminals.
      Fig 9: Identifying Power Seat Motor Connector Terminals
      G04952536Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK 

      HEADREST MOTOR OPERATION CHART

      Measurement Condition Operational Direction
      Battery positive (+) → 5
      Battery negative (-) → 1      		 Upward
      Battery positive (+) → 1
      Battery negative (-) → 5      		 Downward

    NG: REPLACE REAR NO. 1 SEAT HEADREST ADJUSTER SUB-ASSEMBLY  (See DISASSEMBLY  )

    OK: Go to Next Step 

  15. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU RH - REAR HEADREST MOTOR RH) 
    1. Disconnect the f4 ECU connector.
    2. Disconnect the f6 motor connector.
    3. Measure the resistance according to the values in the table below.

      Standard Resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      f4-5 (HUP) - f6-5 Always Below 1 Ω
      f4-1 (HDWN) - f6-1 Always Below 1 Ω
      Fig 10: Identifying f4 ECU And f6 Motor Connector Terminals
      G04952542Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result 

      RESULT CHART

      Result Proceed to
      OK (w/o Ottoman) A
      OK (w/ Ottoman) B
      NG C

    B: REPLACE POSITION CONTROL ECU RH  (See DISASSEMBLY  )

    C: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    A: REPLACE POSITION CONTROL ECU RH  (See DISASSEMBLY  )

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