FRONT POWER SEAT CONTROL SYSTEM, Diagnostic DTC:B2654

DTC Code DTC Name
B2654 Headrest Sensor Malfunction

DESCRIPTION

When the position control ECU assembly does not receive a sensor signal despite upward or downward movement of the seat head rest by power seat motor operation, this DTC is stored.

DTC No. Detection Item DTC Detection Condition Trouble Area
B2654 Headrest Sensor Malfunction The upward and downward lock detection position of the sensor is the same.

  • Position control ECU assembly

  • No. 2 Position control ECU assembly

  • Front seat headrest insert sub-assembly LH (headrest up/down motor)

  • Front seat headrest insert sub-assembly RH (headrest up/down motor)

  • Harness or connector

WIRING DIAGRAM


  1. for Driver Seat:

    Figure 1. for LHD:

    B004TBVE22
    *a SSRH
    *b Headrest Up/Down Motor
    *c Position Control ECU Assembly
    *d Front Seat Headrest Insert Sub-assembly LH

    Figure 2. for RHD:

    B004TBVE23
    *a SSRH
    *b Headrest Up/Down Motor
    *c Position Control ECU Assembly
    *d Front Seat Headrest Insert Sub-assembly RH

  2. for Front Passenger Seat:

    Figure 3. for LHD:

    B004TBVE24
    *a SSRH
    *b Headrest Up/Down Motor
    *c No. 2 Position Control ECU Assembly
    *d Front Seat Headrest Insert Sub-assembly RH

    Figure 4. for RHD:

    B004TBVE25
    *a SSRH
    *b Headrest Up/Down Motor
    *c No. 2 Position Control ECU Assembly
    *d Front Seat Headrest Insert Sub-assembly LH

CAUTION / NOTICE / HINT

Note

Initializing the position control ECU assembly will clear the seat position memory.

Tech Tips


  • Make sure to initialize the position control ECU assembly after replacing the seat assembly or any related parts (including removal and installation).

  • Before initializing the seat ECU, make sure that the D/C CUT fuse is normal.

  • When any of the following conditions are met, the seat position Information in the position control ECU assembly will be cleared.


    • The power switch is turned off with any of the seat switches being operated and the D/C CUT fuse removed.

    • The power switch is turned off within 1 second of any of the seat switches being operated with the D/C CUT fuse removed.

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs.

      Click here


      Body Electrical > Driver Seat > Clear DTCs
      Body Electrical > Passenger Seat > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK FOR DTC


    1. Check for DTCs.

      Click here


      Body Electrical > Driver Seat > Trouble Codes
      Body Electrical > Passenger Seat > Trouble Codes
      OK
      DTC B2654 is not output.
      Result
      Result Proceed to
      DTC B2654 is not output A
      DTC B2654 output from "Driver Seat" B
      DTC B2654 output from "Front Passenger Seat" C

    A

    USE SIMULATION METHOD TO CHECK Click here

    C

    PERFORM ACTIVE TEST USING GTS (HEADREST OPERATION) Click here

    B

  3. PERFORM ACTIVE TEST USING GTS (HEADREST OPERATION)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Driver Seat / Active Test.

    5. Perform the Active Test according to the display on the GTS.


      Body Electrical > Driver Seat > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Headrest Operation Headrest up/down operation OFF/Down/Up -

      Body Electrical > Driver Seat > Active Test
      Tester Display
      Headrest Operation
      OK
      Motor operates normally.
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR) Click here

    OK

  4. CHECK POSITION CONTROL ECU ASSEMBLY (HEADRESTMOTOR CIRCUIT)


    1. for LHD:


      1. Disconnect the front seat headrest insert sub-assembly LH (headrest up/down motor) connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        S17-2 - S17-3 Headrest switch on 4.8 to 5.1 V

    2. for RHD:


      1. Disconnect the front seat headrest insert sub-assembly RH (headrest up/down motor) connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        S9-2 - S9-3 Headrest switch on 4.8 to 5.1 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FRONT SEAT HEADREST INSERT SUB-ASSEMBLY Click here

    NG

  5. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU ASSEMBLY - FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. for LHD:


      1. Disconnect the Q28 position control ECU assembly connector.

      2. Disconnect the S17 front seat headrest assembly LH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q28-14 (SSRH) - S17-3 Always Below 1 Ω
        Q28-14 (SSRH) or S17-3 - Other terminals and body ground Always 10 kΩ or higher
        Q28-16 (SGND) - S17-2 Always Below 1 Ω

    2. for RHD:


      1. Disconnect the Q8 position control ECU assembly connector.

      2. Disconnect the S9 front seat headrest insert sub-assembly RH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q8-14 (SSRH) - S9-3 Always Below 1 Ω
        Q8-14 (SSRH) or S9-3 - Other terminals and body ground Always 10 kΩ or higher
        Q8-16 (SGND) - S9-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE POSITION CONTROL ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. INSPECT FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR)


    1. Remove the front seat headrest insert sub-assembly (headrest up/down motor).

      Click here

    2. Inspect the front seat headrest insert sub-assembly (headrest up/down motor).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FRONT SEAT HEADREST INSERT SUB-ASSEMBLY Click here

    OK

  7. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU ASSEMBLY - FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. for LHD:


      1. Disconnect the Q25 position control ECU assembly connector.

      2. Disconnect the S17 front seat headrest isnert sub-assembly LH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q25-5 (H+) - S17-4 Always Below 1 Ω
        Q25-5 (H+) or S17-4 - Other terminals and body ground Always 10 kΩ or higher
        Q25-4 (H-) - S17-1 Always Below 1 Ω
        Q25-4 (H-) or S17-1 - Other terminals and body ground Always 10 kΩ or higher

    2. for RHD:


      1. Disconnect the Q5 position control ECU assembly connector.

      2. Disconnect the S9 front seat headrest insert sub-assembly RH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q5-5 (H+) - S9-4 Always Below 1 Ω
        Q5-5 (H+) or S9-4 - Other terminals and body ground Always 10 kΩ or higher
        Q5-4 (H-) - S9-1 Always Below 1 Ω
        Q5-4 (H-) or S9-1 - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE POSITION CONTROL ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. PERFORM ACTIVE TEST USING GTS (HEADREST OPERATION)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Passenger Seat / Active Test.

    5. Perform the Active Test according to the display on the GTS.


      Body Electrical > Passenger Seat > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Headrest Operation Headrest up/down operation OFF/Down/Up -

      Body Electrical > Passenger Seat > Active Test
      Tester Display
      Headrest Operation
      OK
      Motor operates normally.
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR) Click here

    OK

  9. CHECK POSITION CONTROL ECU ASSEMBLY (HEADREST MOTOR CIRCUIT)


    1. for LHD:


      1. Disconnect the front seat headrest insert sub-assembly RH (headrest up/down motor) connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        S9-2 - S9-3 Headrest switch on 4.8 to 5.1 V

    2. for RHD:


      1. Disconnect the front seat headrest insert sub-assembly LH (headrest up/down motor) connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        S17-2 - S17-3 Headrest switch on 4.8 to 5.1 V
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FRONT SEAT HEADREST INSERT SUB-ASSEMBLY Click here

    NG

  10. CHECK HARNESS AND CONNECTOR (NO. 2 POSITION CONTROL ECU ASSEMBLY - FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. for LHD:


      1. Disconnect the Q8 No. 2 position control ECU assembly onnector.

      2. Disconnect the S9 front seat headrest insert sub-assembly RH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q8-14 (SSRH) - S9-3 Always Below 1 Ω
        Q8-14 (SSRH) or S9-3 - Other terminals and body ground Always 10 kΩ or higher
        Q8-16 (SGND) - S9-2 Always Below 1 Ω

    2. for RHD:


      1. Disconnect the Q28 No. 2 position control ECU assembly connector.

      2. Disconnect the S17 front seat headrest insert sub-assembly LH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q28-14 (SSRH) - S17-3 Always Below 1 Ω
        Q28-14 (SSRH) or S17-3 - Other terminals and body ground Always 10 kΩ or higher
        Q28-16 (SGND) - S17-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 POSITION CONTROL ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  11. INSPECT FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR)


    1. Remove the front seat headrest insert sub-assembly (headrest up/down motor).

      Click here

    2. Inspect the front seat headrest insert sub-assembly (headrest up/down motor).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE FRONT SEAT HEADREST INSERT SUB-ASSEMBLY Click here

    OK

  12. CHECK HARNESS AND CONNECTOR (NO. 2 POSITION CONTROL ECU ASSEMBLY - FRONT SEAT HEADREST INSERT SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. for LHD:


      1. Disconnect the Q5 No. 2 position control ECU assembly connector.

      2. Disconnect the S9 front seat headrest insert sub-assembly RH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q5-5 (H+) - S9-4 Always Below 1 Ω
        Q5-5 (H+) or S9-4 - Other terminals and body ground Always 10 kΩ or higher
        Q5-4 (H-) - S9-1 Always Below 1 Ω
        Q5-4 (H-) or S9-1 - Other terminals and body ground Always 10 kΩ or higher

    2. for RHD:


      1. Disconnect the Q25 No. 2 position control ECU assembly connector.

      2. Disconnect the S17 front seat headrest insert sub-assembly LH (headrest up/down motor) connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        Q25-5 (H+) - S17-4 Always Below 1 Ω
        Q25-5 (H+) or S17-4 - Other terminals and body ground Always 10 kΩ or higher
        Q25-4 (H-) - S17-1 Always Below 1 Ω
        Q25-4 (H-) or S17-1 - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 POSITION CONTROL ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR