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Home >> Lexus >> 2005 >> SC 430 >> Repair and Diagnosis >> Body & Frame >> Seats >> Front Power Seat Control System (W/Memory) - Diagnostics >> Manual Operation Is Impossible >> Inspection Procedure
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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 J/B.
    2. Remove the P P/SEAT and MPX-B1 fuses from the passenger side J/B.
    3. Remove the D/C CUT fuse from the engine room No. 1 R/B.
    4. Measure the resistance of the fuses.

      Standard: Below 1 Ω 

    1. NG: REPLACE FUSE 
    2. OK: Go to next step. 
  2. INSPECT RELAY (Marking: IG1) 
    1. Remove the IG1 relay from the driver side J/B.
    2. Measure the resistance of the relay.

      Standard: 

      RELAY (MARKING: IG1)

      Tester Connection Specified Condition
      3 - 5 10 k ohms or higher
      3 - 5 Below 1 ohms (when battery voltage is applied to terminals 1 and 2)
      Fig 1: Inspecting Relay (IG1)
      G02956863Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE RELAY 
    2. OK: Go to next step. 
  3. CHECK FRONT POWER SEAT CONTROL FUNCTION (See  ON-VEHICLE INSPECTION   ) 
    1. Check that each function of the power seat operates normally by using the front power seat switches.

      Result: 

      FRONT POWER SEAT CONTROL FUNCTION

      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
    1. B: Go to step   8 
    2. A: Go to next step. 
  4. READ DATA LIST (FRONT POWER SEAT SWITCH ASSY) 
    1. Check the DATA LIST for proper functioning of the front power seat switch.

      Position control ECU assy (driver, passenger side): 

      Fig 2: Front Power Seat Switch Assy Data List
      G02956864Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: 

      On tester screen, each item changes between ON and OFF according to  Fig 2 . 

    1. NG: Go to step   6 
    2. OK: REPLACE POSITION CONTROL ECU ASSY 
  5. INSPECT FRONT POWER SEAT SWITCH (SLIDE SWITCH, FRONT VERTICAL SWITCH, LIFTER SWITCH, RECLINING SWITCH) 
    1. Measure the resistance between the terminals when the each switch is operated.

      Standard: 

      Front power seat switch LH 

      Slide switch 

      FRONT POWER SEAT SWITCH LH - SLIDE SWITCH

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

      Front vertical switch 

      FRONT POWER SEAT SWITCH LH - FRONT VERTICAL SWITCH

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

      Lifter switch 

      FRONT POWER SEAT SWITCH LH - LIFTER SWITCH

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

      Reclining switch 

      FRONT POWER SEAT SWITCH LH - RECLINING SWITCH

      Tester Connection Switch Condition Specified Condition
      1 (E) - 3 (RCLF) FORWARD Below 1 ohms
      1 (E) - 2 (RCLR) REAR Below 1 ohms
      Fig 3: Measuring Resistance Between Terminals (LH)
      G02956865Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Front power seat switch RH 

      Slide switch 

      FRONT POWER SEAT SWITCH RH - SLIDE SWITCH

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

      Front vertical switch 

      FRONT POWER SEAT SWITCH RH - FRONT VERTICAL SWITCH

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

      Lifter switch 

      FRONT POWER SEAT SWITCH RH - LIFTER SWITCH

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

      Reclining switch 

      FRONT POWER SEAT SWITCH RH - RECLINING SWITCH

      Tester Connection Switch Condition Specified Condition
      1 (E) - 3 (RCLF) FORWARD Below 1 ohms
      1 (E) - 2 (RCLR) REAR Below 1 ohms
      Fig 4: Measuring Resistance Between Terminals (RH)
      G02956866Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE FRONT POWER SEAT SWITCH 
    2. OK: Go to next step. 
  6. INSPECT POWER SEAT MOTOR ASSY (SLIDE MOTOR, VERTICAL MOTOR, LIFTER MOTOR, RECLINING MOTOR) 
    1. Check operation of the slide motor.
      1. Check the motor rotation when the battery is connected to the slide motor connector terminals.

        OK: 

        OPERATION OF SLIDE MOTOR

        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 Slide Motor
        G02956867Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check operation of the vertical motor.
      1. Check the motor rotation when the battery is connected to the vertical motor connector terminals.

        OK: 

        OPERATION OF VERTICAL MOTOR

        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 Front Vertical Motor
        G02956868Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check operation of the lifter motor.
      1. Check the motor rotation when the battery is connected to the lifter motor connector terminals.

        OK: 

        OPERATION OF LIFTER MOTOR

        Measurement Condition Specified Condition
        Battery positive (+) -> 1
        Battery negative (-) -> 2        		 Rotates smoothly counterclockwise
        Battery positive (+) -> 2
        Battery negative (-) -> 1        		 Rotates smoothly clockwise
        Fig 7: Checking Operation Of Lifter Motor
        G02956869Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Check operation of the reclining motor.
      1. Check the motor rotation when the battery is connected to the reclining motor connector terminals.

        OK: 

        OPERATION OF RECLINING MOTOR

        Measurement Condition Specified Condition
        Battery positive (+) -> 1
        Battery negative (-) -> 2        		 Rotates smoothly counterclockwise
        Battery positive (+) -> 2
        Battery negative (-) - 1        		 Rotates smoothly clockwise
        Fig 8: Checking Operation Of Reclining Motor
        G02956870Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE POWER SEAT MOTOR ASSY 
    2. OK: Go to next step. 
  7. CHECK WIRE HARNESS (POSITION CONTROL ECU LH OR RH - BATTERY AND BODY GROUND) 
    1. Disconnect the P21, P22, P23 or P24 ECU connectors.
    2. Measure the voltage and resistance of the wire harness side connectors.

      Standard: 

      Driver side 

      POSITION CONTROL ECU LH OR RH - BATTERY AND BODY GROUND (DRIVER SIDE)

      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 0 V
      P22-8 (+B) - Body ground Always 10 to 14 V
      P21-9 (SYSB) - Body ground Always 10 to 14 V
      P21-13 (SGND) - Body ground Always Below 1 ohms
      P22-7 (GND) - Body ground Always Below 1 ohms

      Passenger side 

      POSITION CONTROL ECU LH OR RH - BATTERY AND BODY GROUND (DRIVER SIDE)

      Tester Connection Condition Specified Condition
      P24-8 (+B) Body ground Always 10 to 14 V
      P23-9 (SYSB) - Body ground Always 10 to 14 V
      P23-13 (SGND) - Body ground Always Below 1 ohms
      P24-7 (GND) - Body ground Always Below 1 ohms
      Fig 9: Checking Wire Harness (Position Control ECU LH Or RH - Battery & Body Ground)
      G02956871Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: REPLACE POSITION CONTROL ECU ASSY 
  8. CHECK WIRE HARNESS (LUMBAR FRONT POWER SEAT SWITCH - POSITION CONTROL ECU ASSY AND BODY GROUND) 
    1. Disconnect the L27 or L28 switch connector.
    2. Disconnect the P22 or P24 ECU connector.
    3. Measure the resistance of the wire harness side connectors.

      Standard: 

      Driver side 

      LUMBAR FRONT POWER SEAT SWITCH - POSITION CONTROL ECU ASSY AND BODY GROUND (DRIVER SIDE)

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

      Passenger side 

      LUMBAR FRONT POWER SEAT SWITCH - POSITION CONTROL ECU ASSY AND BODY GROUND (PASSENGER SIDE)

      Tester Connection Specified Condition
      L28-1 (B) - P24-8 (+B) Below 1 ohms
      L28-2 (E) - Body ground Below 1 ohms
      Fig 10: Checking Wire Harness (Lumbar Front Power Seat Switch - Position Control ECU Assy & Body Ground)
      G02956872Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: Go to next step. 
  9. INSPECT LUMBAR FRONT POWER SEAT SWITCH 
    1. Remove the switch.
    2. Measure the resistance of the seat switch.

      Standard: 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      1 (LR) - 3 (E2)
      1 (LR) - 4 (B2)      		 FRONT Below 1 ohms
      2 (LH) - 3 (E2)
      2 (LH) - 4 (B2)      		 BACK Below 1 ohms
      Fig 11: Inspecting Lumbar Front Power Seat Switch
      G02956873Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE LUMBAR FRONT POWER SEAT SWITCH 
    2. OK: Go to next step. 
  10. CHECK POWER SEAT MOTOR ASSY (LUMBAR SUPPORT ADJUSTER MOTOR) 
    1. Check operation of the lumbar support adjuster motor.
      1. Check the motor rotation when the battery is connected to the lumbar support adjuster motor connector terminals.

        OK: 

        POWER SEAT MOTOR ASSY (LUMBAR SUPPORT ADJUSTER MOTOR)

        Measurement Condition Specified Condition
        Battery positive (+) -> 1
        Battery negative (-) -> 2        		 Rotates smoothly clockwise
        Battery positive (+) -> 2
        Battery negative (-) -> 1        		 Rotates smoothly counterclockwise
        Fig 12: Checking Power Seat Motor Assy (Lumbar Support Adjuster Motor)
        G02956874Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE POWER SEAT MOTOR ASSY 
    2. OK: REPAIR OR REPLACE HARNESS AND CONNECTOR 
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