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Home >> Lexus >> 2007 >> SC 430 >> Repair and Diagnosis >> Body & Frame >> Seats >> Seat >> Front Power Seat Control System >> Front Power Seat does not Operate with Front Power Seat Switch >> Inspection Procedure

Inspection Procedure

  1. INSPECT FUSE (D P/SEAT, P P/SEAT, MPX-IG, MPX-B1, D/C CUT, AM1) 
    1. Remove the D P/SEAT MPX-IG and AM1 fuses from the driver side junction block.
    2. Remove the P P/SEAT and MPX-B1 fuses from the front passenger side junction block.
    3. Remove the D/C CUT fuse from the engine room No. 1 relay block.
    4. Measure the resistance of the fuses.

      Standard resistance: Below 1 Ω 

    NG: REPLACE FUSE 

    OK: Go to Next Step 

  2. INSPECT IGNITION RELAY NO. 1 
    Fig 1: Identifying IG1 Relay
    G05293683Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the IG1 relay from the driver side junction block.
    2. Measure the resistance of the relay.

      Standard resistance 

      RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      3-5 10 kΩ or higher
      3-5 Below 1 Ω (when battery voltage is applied to terminals 1 and 2)

    NG: REPLACE IGNITION RELAY NO. 1 

    OK: Go to Next Step 

  3. CHECK FRONT POWER SEAT CONTROL FUNCTION 
    1. Check that each function of the power seat operates normally by using the front power seat switches.

      Result: 

      RESULT CHART

      Result Proceed to
      All front power switch operations are malfunctioning except lumbar front power seat switch operation A
      Only lumbar front power seat switch operation is malfunctioning B

    B: Go to step  8

    A: Go to Next Step 

  4. READ VALUE OF INTELLIGENT TESTER (FRONT POWER SEAT SWITCH) 
    1. Check the DATA LIST for proper functioning of the front power seat switch.

      Position control ECU (for driver, front passenger side) 

      DATA LIST

      Item Measurement Item/ Range (Display) Normal Condition Diagnostic Note
      RECLIN SW REAR Reclining switch signal (Rearward)/ ON or OFF ON: Reclining switch (Rearward) is ON
      OFF: Reclining switch (Rearward) is OFF      		 -
      RECLIN SW FRONT Reclining switch signal (Forward)/ ON or OFF ON: Reclining switch (Forward) is ON
      OFF: Reclining switch (Forward) is OFF      		 -
      F VTCL SW DOWN Front vertical switch signal (Downward)/ ON or OFF ON: Front vertical switch (Downward) is ON
      OFF: Front vertical switch (Downward) is OFF      		 -
      F VTCL SW UP Front vertical switch signal (Upward)/ ON or OFF ON: Front vertical switch (Upward) is ON
      OFF: Front vertical switch (Upward) is OFF      		 -
      LIFTER SW DOWN Lifter switch signal (Downward)/ ON or OFF ON: Lifter switch (Downward) is ON
      OFF: Lifter switch (Downward) is OFF      		 -
      LIFTER SW UP Lifter switch signal (Upward)/ ON or OFF ON: Lifter switch (Upward) is ON
      OFF: Lifter switch (Upward) is OFF      		 -
      SLIDE SW REAR Sliding switch signal (Rearward)/ ON or OFF ON: Sliding switch (Rearward) is ON
      OFF: Sliding switch (Rearward) is OFF      		 -
      SLIDE SW FRONT Sliding switch signal (Forward)/ ON or OFF ON: Sliding switch (Forward) is ON
      OFF: Sliding switch (Forward) is OFF      		 -

      OK: On tester screen, each item changes between ON and OFF according to above chart. 

    NG: Go to step  6

    OK: REPLACE POSITION CONTROL ECU 

  5. INSPECT FRONT POWER SEAT SWITCH (SLIDE SWITCH, FRONT VERTICAL SWITCH, LIFTER SWITCH, RECLINING SWITCH) 
    1. Measure the resistance between the terminals when each switch is operated.
      1. Front power seat switch LH

        Standard resistance: 

        Slide switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 9 (SLDF) FRONT Below 1 Ω
        1 (E) - 6 (SLDR) BACK Below 1 Ω

        Front vertical switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 10 (FUP) UP Below 1 Ω
        1 (E) - 5 (FDWN) DOWN Below 1 Ω

        Lifter switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 7 (LUP) UP Below 1 Ω
        1 (E) - 8 (LDWN) DOWN Below 1 Ω
        Fig 2: Inspecting Front Power Seat Switch LH
        G05293684Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Reclining switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 3 (RCLF) FORWARD Below 1 Ω
        1 (E) - 2 (RCLR) REAR Below 1 Ω
      2. Front power seat switch RH

        Standard resistance: 

        Slide switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 9 (SLDF) FRONT Below 1 Ω
        1 (E) - 6 (SLDR) BACK Below 1 Ω

        Front vertical switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 10 (FUP) UP Below 1 Ω
        1 (E) - 5 (FDWN) DOWN Below 1 Ω

        Lifter switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 7 (LUP) UP Below 1 Ω
        1 (E) - 8 (LDWN) DOWN Below 1 Ω

        Reclining switch 

        RESISTANCE SPECIFICATION

        Tester Connection Switch Condition Specified Condition
        1 (E) - 3 (RCLF) FORWARD Below 1 Ω
        1 (E) - 2 (RCLR) REAR Below 1 Ω
        Fig 3: Inspecting Front Power Seat Switch RH
        G05293685Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE FRONT POWER SEAT SWITCH 

    OK: Go to Next Step 

  6. INSPECT POWER SEAT MOTOR ASSEMBLY (SLIDE MOTOR, VERTICAL MOTOR, LIFTER MOTOR, RECLINING MOTOR) 
    1. Check the operation of the slide motor.
      1. Check the motor rotation when the battery is connected to the slide motor connector terminals.
        MEASUREMENT CONDITION AND SPECIFIED CONDITION CHART

        Measurement Condition Specified Condition
        Battery positive (+) → 1
        Battery negative (-) → 2        		 Rotates smoothly counterclockwise
        Battery positive* (+) → 2
        Battery negative (-) → 1        		 Rotates smoothly clockwise
        Fig 4: Checking Operation Of Slide Motor
        G05293686Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check the operation of the vertical motor.
      1. Check the motor rotation when the battery is connected to the vertical motor connector terminals.

        OK 

        MEASUREMENT CONDITION AND SPECIFIED CONDITION CHART

        Measurement Condition Specified Condition
        Battery positive (+) → 1
        Battery negative (-) → 2        		 Rotates smoothly counterclockwise
        Battery positive (+) → 2
        Battery negative (-) → 1        		 Rotates smoothly clockwise
        Fig 5: Checking Operation Of Vertical Motor
        G05293687Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the operation of the lifter motor.
      1. Check the motor rotation when the battery is connected to the lifter motor connector terminals.
        MEASUREMENT CONDITION AND SPECIFIED CONDITION CHART

        Measurement Condition Specified Condition
        Battery positive (+) → 1
        Battery negative (-) → 2        		 Rotates smoothly counterclockwise
        Battery positive (+) → 2
        Battery negative (-) → 1        		 Rotates smoothly clockwise
        Fig 6: Checking Operation Of Lifter Motor
        G05293688Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Check the operation of the reclining motor.
      Fig 7: Checking Operation Of Reclining Motor
      G05293689Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Check the motor rotation when the battery is connected to the reclining motor connector terminals.

        OK 

        MEASUREMENT CONDITION AND SPECIFIED CONDITION CHART

        Measurement Condition Specified Condition
        Battery positive (+) → 1
        Battery negative (-) → 2        		 Rotates smoothly counterclockwise
        Battery positive (+) → 2
        Battery negative (-) → 1        		 Rotates smoothly clockwise

    NG: REPLACE POWER SEAT MOTOR ASSEMBLY 

    OK: Go to Next Step 

  7. CHECK WIRE HARNESS (POSITION CONTROL ECU LH - BATTERY AND BODY GROUND) 
    1. Disconnect the P21, P22, P23 or P24 ECU connectors.
    2. Measure the voltage of the wire harness side connectors.

      Standard voltage: 

      for Driver Side 

      VOLTAGE SPECIFICATION

      Tester Connection Condition Specified Condition
      P21-8 (IG) - Body ground Ignition switch ON 10 to 14 V
      P21-8 (IG) - Body ground Ignition switch OFF Below 1 V
      P22-8 (+B) - Body ground Always 10 to 14 V
      P21-9 (SYSB) - Body ground Always 10 to 14 V

      for Front Passenger Side 

      VOLTAGE SPECIFICATION

      Tester Connection Specified Condition
      P24-8 (+B) - Body ground 10 to 14 V
      P23-9 (SYSB) - Body ground 10 to 14 V
      Fig 8: Identifying P21, P22, P23 Or P24 ECU Connectors
      G05293690Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance of the wire harness side connectors.

      Standard resistance: 

      for Driver Side 

      RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      P21-13 (SGND) - Body ground Below 1 Ω
      P22-7 (GND) - Body ground Below 1 Ω

      for Front Passenger Side 

      RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      P23-13 (SGND) - Body ground Below 1 Ω
      P24-7 (GND) - Body ground Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE POSITION CONTROL ECU 

  8. CHECK WIRE HARNESS (LUMBAR FRONT POWER SEAT SWITCH - POSITION CONTROL ECU AND BODY GROUND) 
    1. Disconnect the L27 or L28 switch connector.
    2. Disconnect the P22 or P24 ECU connector.
      Fig 9: Identifying L27 Or L28 Switch Connector And P22 Or P24 ECU Connector
      G05293691Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance of the wire harness side connectors.

      Standard resistance: 

      for Driver Side 

      RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      L27-4 (B2) - P22-8 (+B) Below 1 Ω
      L27-3 (E2) - Body ground Below 1 Ω

      for Front Passenger Side 

      RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      L28-1 (B) - P24-8 (+B) Below 1
      L28-2 (E) - Body ground Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  9. INSPECT LUMBAR FRONT POWER SEAT SWITCH 
    Fig 10: Inspecting Lumbar Front Power Seat Switch
    G05293692Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the switch.
    2. Measure the resistance of the seat switch.

      Standard resistance: 

      for Driver Side 

      RESISTANCE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      1 (LF) - 4 (B2) 2 (LR) - 3 (B2) FRONT Below 1 Ω
      1 (LF) - 3 (E2) 2 (LR) - 3 (B2) OFF Below 1 Ω
      1 (LF) - 3 (E2) 2 (LR) - 4 (B2) BACK Below 1 Ω

      for Front Passenger Side 

      RESISTANCE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      1 (B) - 4 (LF) 2 (E) - 3 (LR) FRONT Below 1 Ω
      2 (E) - 3 (LR) 2 (E) - 4 (LF) OFF Below 1 Ω
      1 (B) - 3 (LR) 2 (E) - 4 (LF) BACK Below 1 Ω

    NG: REPLACE LUMBAR FRONT POWER SEAT SWITCH 

    OK: Go to Next Step 

  10. CHECK POWER SEAT MOTOR ASSEMBLY (LUMBAR SUPPORT ADJUSTER MOTOR) 
    1. Check the operation of the lumbar support adjuster motor.
      Fig 11: Checking Operation Of Lumbar Support Adjuster Motor
      G05293693Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Check the motor rotation when the battery is connected to the lumbar support adjuster motor connector terminals.

        OK 

        MEASUREMENT CONDITION AND SPECIFIED CONDITION CHART

        Measurement Condition Specified Condition
        Battery positive (+) → 1
        Battery negative (-) → 2        		 Rotates smoothly clockwise
        Battery positive (+) → 2
        Battery negative (-) → 1        		 Rotates smoothly counterclockwise

    NG: REPLACE POWER SEAT MOTOR ASSEMBLY 

    OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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