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REAR POWER SEAT CONTROL SYSTEM, Diagnostic DTC:B2654

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DTC Code DTC Name
B2654 Headrest Sensor Malfunction
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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 LH

  • Position control ECU assembly RH

  • Rear No. 2 seat headrest adjuster sub-assembly (headrest up/down motor)

  • Rear No. 1 seat headrest adjuster sub-assembly (headrest up/down motor)

  • Harness or connector
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WIRING DIAGRAM


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  1. Figure 2. for RHD: B004SB4E98
    Table 2.
    *a SSRH
    *b Headrest Up/Down Motor
    *c Position Control ECU Assembly RH
    *d Rear No. 1 Seat Headrest Adjuster Sub-assembly
    Figure 1. for LHD: B004SB4E97
    Table 1.
    *a SSRH
    *b Headrest Up/Down Motor
    *c Position Control ECU Assembly RH
    *d Rear No. 2 Seat Headrest Adjuster Sub-assembly

    for Rear Seat RH:

  2. Figure 4. for RHD: B004TBVE01
    Table 4.
    *a SSRH
    *b Headrest Up/Down Motor
    *c Position Control ECU Assembly LH
    *d Rear No. 2 Seat Headrest Adjuster Sub-assembly
    Figure 3. for LHD: B004SB4E99
    Table 3.
    *a SSRH
    *b Headrest Up/Down Motor
    *c Position Control ECU Assembly LH
    *d Rear No. 1 Seat Headrest Adjuster Sub-assembly

    for Rear Seat LH:

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CAUTION / NOTICE / HINT

Note:

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

Tip:

  • 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.

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PROCEDURE


  1. Click here

    CLEAR DTC


    1. Clear the DTCs.

      Click here


      1. Body Electrical > Rear Right Seat > Clear DTCs



      1. Body Electrical > Rear Left Seat > Clear DTCs


      Result
      Proceed to
      NEXT

  2. Click here

    CHECK FOR DTC


    1. Check for DTCs.

      Click here


      1. Body Electrical > Rear Right Seat > Trouble Codes



      1. Body Electrical > Rear Left Seat > Trouble Codes


      OK
      DTC B2654 is not output.
      Result
      Result Proceed to
      DTC B2654 is not output A
      DTC B2654 output from "Rear Right Seat" B
      DTC B2654 output from "Rear Left Seat" C

  3. Click here

    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 / Rear Right Seat / Active Test.

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


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



      1. Body Electrical > Rear Right Seat > Active Test
        Tester Display
        Headrest Operation




      OK
      Motor operates normally.
      Result
      Proceed to
      OK
      NG

  4. Click here

    CHECK POSITION CONTROL ECU ASSEMBLY RH (HEADRST MOTOR CIRCUIT)


    1. Disconnect the rear seat headrest adjuster sub-assembly (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
      R2-2 - R2-3 Headrest switch on 4.8 to 5.1 V
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

  5. Click here

    CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU ASSEMBLY RH - REAR SEAT HEADREST ADJUSTER SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. Disconnect the R7 position control ECU assembly RH connector.

    2. Disconnect the R2 rear No. 2 seat headrest adjuster sub-assembly*1 or rear No. 1 seat headrest adjuster sub-assembly*2 (headrest up/down motor) connector.


      • *1: for LHD

      • *2: for RHD

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      R7-26 (SSRH) - R2-3 Always Below 1 Ω
      R7-26 (SSRH) or R2-3 - Other terminals and body ground Always 10 kΩ or higher
      R7-7 (SGND) - R2-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE POSITION CONTROL ECU ASSEMBLY RHClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. Click here

    INSPECT REAR SEAT HEADREST ADJUSTER SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR)


    1. for LHD:


      1. Remove the rear No. 2 seat headrest adjuster sub-assembly.

        Click here

      2. Inspect the rear No. 2 seat headrest adjuster sub-assembly.

        Click here

    2. for RHD:


      1. Remove the rear No. 1 seat headrest adjuster sub-assembly.

        Click here

      2. Inspect the rear No. 1 seat headrest adjuster sub-assembly.

        Click here

      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

  7. Click here

    CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU ASSEMBLY RH - REAR SEAT HEADREST ADJUSTER SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. Disconnect the R4 and R5 position control ECU assembly RH connectors.

    2. Disconnect the R2 rear No. 2 seat headrest adjuster sub-assembly*1 or rear No. 1 seat headrest adjuster sub-assembly*2 connector


      • *1: for LHD

      • *2: for RHD

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      R5-9 (H+) - R2-4 Always Below 1 Ω
      R5-9 (H+) or R2-4 - Other terminals and body ground Always 10 kΩ or higher
      R4-5 (H-) - R2-1 Always Below 1 Ω
      R4-5 (H-) or R2-1 - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE POSITION CONTROL ECU ASSEMBLY RHClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. Click here

    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 / Rear Left Seat / Active Test.

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


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



      1. Body Electrical > Rear Left Seat > Active Test
        Tester Display
        Headrest Operation




      OK
      Motor operates normally.
      Result
      Proceed to
      OK
      NG

  9. Click here

    CHECK POSITION CONTROL ECU ASSEMBLY LH (HEADRST MOTOR CIRCUIT)


    1. Disconnect the rear seat headrest adjuster sub-assembly (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
      R36-2 - R36-3 Headrest switch on 4.8 to 5.1 V
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

  10. Click here

    CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU ASSEMBLY LH - REAR SEAT HEADREST ADJUSTER SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. Disconnect the R41 position control ECU assembly LH connector.

    2. Disconnect the R36 rear No. 1 seat headrest adjuster sub-assembly*1 or rear No. 2 seat headrest adjuster sub-assembly*2 (headrest up/down motor) connector.


      • *1: for LHD

      • *2: for RHD

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      R41-26 (SSRH) - R36-3 Always Below 1 Ω
      R41-26 (SSRH) or R36-3 - Other terminals and body ground Always 10 kΩ or higher
      R41-7 (SGND) - R36-2 Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE POSITION CONTROL ECU ASSEMBLY LHClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

  11. Click here

    INSPECT REAR SEAT HEADREST ADJUSTER SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR)


    1. for LHD:


      1. Remove the rear No. 1 seat headrest adjuster sub-assembly.

        Click here

      2. Inspect the rear No. 1 seat headrest adjuster sub-assembly.

        Click here

    2. for RHD:


      1. Remove the rear No. 2 seat headrest adjuster sub-assembly.

        Click here

      2. Inspect the rear No. 2 seat headrest adjuster sub-assembly.

        Click here

      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

  12. Click here

    CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU ASSEMBLY LH - REAR SEAT HEADREST ADJUSTER SUB-ASSEMBLY (HEADREST UP/DOWN MOTOR))


    1. Disconnect the R38 and R39 position control ECU assembly RH connectors.

    2. Disconnect the R36 rear No. 1 seat headrest adjuster sub-assembly*1 or rear No. 2 seat headrest adjuster sub-assembly*2 connector


      • *1: for LHD

      • *2: for RHD

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      R39-9 (H+) - R36-4 Always Below 1 Ω
      R39-9 (H+) or R36-4 - Other terminals and body ground Always 10 kΩ or higher
      R38-5 (H-) - R36-1 Always Below 1 Ω
      R38-5 (H-) or R36-1 - Other terminals and body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE POSITION CONTROL ECU ASSEMBLY LHClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR