FRONT POWER SEAT CONTROL SYSTEM Power Seat Position is not Memorized

DESCRIPTION

The main body ECU (multiplex network body ECU) receives seat memory switch (for Driver Seat) signals from the front multiplex network door ECU (for Driver Seat) via CAN communication. If the seat memory SET switch is being pressed when one of the M1, M2 or M3 switches is pressed, or if one of the M1, M2 or M3 switches is pressed within 3 seconds of pressing the seat memory SET switch, the main body ECU (multiplex network body ECU) sends a memory request signal to the position control ECU assembly (for Driver Seat). After receiving the request signal, the position control ECU assembly (for Driver Seat) memorizes the location data of each motor.

WIRING DIAGRAM

B000U49E03

CAUTION / NOTICE / HINT

Note


  • The seat position will not be stored if the SET switch and 2 or more of the seat memory switches (for example, M1 switch and M2 switch) are pressed simultaneously.

    If a memorizing operation has failed, release all switches. The seat memory function does not operate unless the switches are released.

  • The seat will not return to the memorized position if 2 or more of the seat memory switches (for example, M1 switch and M2 switch) are pressed simultaneously.

    If a restoring operation has failed, release all switches. The seat memory restoring function does not operate unless the switches are released.

  • The front power seat control system uses the CAN communication system. First, confirm that there are no malfunctions in the CAN communication system. Refer to How to Proceed with Troubleshooting.

    Click here

  • Before replacing the main body ECU (multiplex network body ECU), refer to Service Bulletin.

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

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

PROCEDURE


  1. CHECK FRONT POWER SEAT CONTROL OPERATION


    1. Check that each function of the power seat operates normally by using the front power seat switch (for Driver Seat).

      Click here

      OK
      Each function of the power seat operates normally using the front power seat switch (for Driver Seat).
      Result
      Proceed to
      OK
      NG

    NG

    GO TO PROBLEM SYMPTOMS TABLE Click here

    OK

  2. READ VALUE USING GTS (SEAT MEMORY SWITCH1, SEAT MEMORY SWITCH2, SEAT MEMORY SWITCH3, SAET MEMORY SET SW)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Mirror L / Data List.

    5. Read the Data List according to the display on the GTS.


      Body Electrical > Front Left Door > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Seat Memory Switch1 M1 switch ON or OFF

      ON: M1 switch on

      OFF: M1 switch off

      		 -
      Seat Memory Switch2 M2 switch ON or OFF

      ON: M2 switch on

      OFF: M2 switch off

      		 -
      Seat Memory Switch3 M3 switch ON or OFF

      ON: M3 switch on

      OFF: M3 switch off

      		 -
      Seat Memory Set SW SET switch ON or OFF

      ON: SET switch on

      OFF: SET switch off

      		 -

      Body Electrical > Front Left Door > Data List
      Tester Display
      Seat Memory Switch1
      Seat Memory Switch2
      Seat Memory Switch3
      Seat Memory Set SW
      OK
      ON or OFF is displayed on the GTS according to the table above.
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT SEAT MEMORY SWITCH Click here

    OK

  3. PERFORM ACTIVE TEST USING GTS (BUZZER)


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

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

    5. Read the Data List according to the display on the GTS.


      Body Electrical > Driver Seat > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      Buzzer Buzzer operation OFF/ON -

      Body Electrical > Driver Seat > Active Test
      Tester Display
      Buzzer
      OK
      Buzzer sounds normally.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE POSITION CONTROL ECU ASSEMBLY (FOR DRIVER SEAT) Click here

    OK

  4. REPLACE FRONT MULTIPLEX NETWORK DOOR ECU (FOR DRIVER SEAT)


    1. Temporarily replace the outer front multiplex network door ECU (for Driver Seat) with a new or known good one.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK SEAT POSITION MEMORY AND RESTORING FUNCTION


    1. Check that the seat position memory and restoring function.

      Click here

      OK
      Seat position memory and restoring function operate normally.
      Result
      Proceed to
      OK
      NG

    OK

    END (FRONT MULTIPLEX NETWORK DOOR ECU (FOR DRIVER SEAT) WAS DEFECTIVE)

    NG

  6. REPLACE POSITION CONTROL ECU ASSEMBLY (FOR DRIVER SEAT)


    1. Temporarily replace the position control ECU assembly (for Driver Seat) with a new or known good one.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK SEAT POSITION MEMORY AND RESTORING FUNCTION


    1. Check that the seat position memory and restoring function.

      Click here

      OK
      Seat position memory and restoring function operate normally.
      Result
      Proceed to
      OK
      NG

    OK

    END (POSITION CONTROL ECU ASSEMBLY (FOR DRIVER SEAT) WAS DEFECTIVE)

    NG

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

  8. INSPECT SEAT MEMORY SWITCH


    1. Remove the seat memory switch.

      Click here

    2. Inspect the seat memory switch.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE SEAT MEMORY SWITCH Click here

    OK

  9. CHECK HARNESS AND CONNECTOR (FRONT MULTIPLEX NETWORK DOOR ECU (FOR DRIVER SEAT) - SEAT MEMORY SWITCH AND BODY GROUND)


    1. for LHD:


      1. Disconnect the S9 front multiplex network door ECU LH connector.

      2. Disconnect the U6 seat memory switch connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        S9-25 (MM) - U6-1 (MRY) Always Below 1 Ω
        S9-25 (MM) or U6-1 (MRY) - Other terminals and body ground Always 10 kΩ or higher
        S9-22 (M1) - U6-2 (M1) Always Below 1 Ω
        S9-22 (M1) or U6-2 (M1) - Other terminals and body ground Always 10 kΩ or higher
        S9-23 (M2) - U6-4 (M2) Always Below 1 Ω
        S9-23 (M2) or U6-4 (M2)- Other terminals and body ground Always 10 kΩ or higher
        S9-24 (M3) - U6-5 (M3) Always Below 1 Ω
        S9-24 (M3) or U6-5 (M3) - Other terminals and body ground Always 10 kΩ or higher
        S9-1 (GND) - Body ground Always Below 1 Ω

    2. for RHD:


      1. Disconnect the R9 front multiplex network door ECU RH connector.

      2. Disconnect the T6 seat memory switch connector.

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

        Standard Resistance
        Tester Connection Condition Specified Condition
        R9-25 (MM) - T6-1 (MRY) Always Below 1 Ω
        R9-25 (MM) or T6-1 (MRY) - Other terminals and body ground Always 10 kΩ or higher
        R9-22 (M1) - T6-2 (M1) Always Below 1 Ω
        R9-22 (M1) or T6-2 (M1) - Other terminals and body ground Always 10 kΩ or higher
        R9-23 (M2) - T6-4 (M2) Always Below 1 Ω
        R9-23 (M2) or T6-4 (M2)- Other terminals and body ground Always 10 kΩ or higher
        R9-24 (M3) - T6-5 (M3) Always Below 1 Ω
        R9-24 (M3) or T6-5 (M3) - Other terminals and body ground Always 10 kΩ or higher
        R9-1 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE FRONT MULTIPLEX NETWORK DOOR ECU (FOR DRIVER SEAT) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR