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Home >> Lexus >> 2002 >> SC 430 >> Repair and Diagnosis >> Body & Frame >> Seats >> Front Power Seat Control System (W/Memory) - Diagnosis >> Manual Operation Is Impossible >> Inspection Procedure

Inspection Procedure

  1. FUNCTION CHECK 
    1. Check that each function of the power seat operates normally by using each switch of the power seat.
      1. When no function operates normally, proceed to "A".
      2. When a part of the functions operates normally, proceed to "B".
    1. B: GO TO STEP   8 
    2. A: GO TO NEXT STEP. 
  2. CHECK FUSES 
    1. Check whether D-SEAT fuse and P-SEAT fuse operate normally.
    1. NG: REPLACE FUSES 
    2. OK: GO TO NEXT STEP. 
  3. CHECK SOURCE VOLTAGE 
    1. Disconnect the seat ECU connector and connect the seat wire harness to the floor wire harness.
    2. Inspect the connector on the wire harness side.
    Fig 1: Checking Source Voltage Connector P21 & P22
    G03386943Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    TESTER CONNECTION CHART

    Tester connection Condition Specified condition
    P21-8 <--> Ground IG SW ON 10-14 V
    P22-8 <--> Ground Constant 10-14 V
    P21-9 <--> Ground Constant 10-14 V
    NOTE: If circuit is not as specified, inspect the circuits connected to other parts.
    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: GO TO NEXT STEP. 
  4. CHECK CONTINUITY 
    1. Disconnect the seat ECU connector and inspect the connector on the wire harness side.
    Fig 2: Checking Continuity Connector P21 & P22
    G03386944Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    TESTER CONNECTION CHART

    Tester connection Condition Specified condition
    P22-7 <--> Ground Constant Continuity
    NOTE: If circuit is not as specified, inspect the circuits connected to other parts.
    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: GO TO NEXT STEP. 
  5. INSPECT FRONT POWER SEAT SWITCH RH 
    1. Inspect the front power seat switch RH continuity.

      Slide switch : 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      FRONT 1 <--> 9 Continuity
      BACK 1 <--> 6 Continuity

      Front vertical switch: 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      Up 1 <--> 10 Continuity
      Down 1 <--> 5 Continuity

      Lifter switch: 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      Up 1 <--> 7 Continuity
      Down 1 <--> 8 Continuity

      Reclining switch: 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      FORWARD 1 <--> 3 Continuity
      REAR 1 <--> 2 Continuity
    2. Inspect the front power seat switch LH continuity.

      Slide switch: 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      FRONT 1 <--> 9 Continuity
      BACK 1 <--> 6 Continuity
      Fig 3: Inspecting Front Power Seat Switch LH Continuity
      G03386945Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Front vertical switch: 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      Up 1 <--> 5 Continuity
      Down 1 <--> 10 Continuity

      Lifter switch: 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      Up 1 <--> 8 Continuity
      Down 1 <-->7 Continuity

      Reclining switch: 

      TESTER CONNECTION CHART

      Switch position Tester connection Specified condition
      FORWARD 1 <--> 3 Continuity
      REAR 1 <--> 2 Continuity
    1. NG: REPLACE FRONT POWER SEAT SWITCH RH 
    2. OK: GO TO NEXT STEP. 
  6. DO ACTIVE TEST OF LEXUS HAND-HELD TESTER 
    1. Connect the LEXUS hand-held tester to the DLC3.
    2. Enter into ACTIVE TEST function of LEXUS hand-held tester.

    SEAT ECU 

    ACTIVE TEST CHART

    Item Condition
    RECLINING FRONT/REAR FRONT/REAR
    Fr VERTCAL UP/DOWN UP/DOWN
    Rr VERTCAL UP/DOWN UP/DOWN
    SEAT SLIDE FRONT/REAR FRONT/REAR
    1. OK: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. NG: GO TO NEXT STEP. 
  7. INSPECT POWER SEAT MOTOR ASSY 
    1. Inspect the motor with a malfunctioning part detected by an active test.
      1. Connect the positive (+) lead from the battery to terminal 2 and the negative (-) lead to terminal 1 and check that the motor turns clockwise.
      2. Reverse the polarity and check that the motor turns counterclockwise.
      Fig 4: Inspecting Power Seat Motor Assy
      G03386946Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    NOTE: If operation is not as specified, replace the motor.
    1. NG: REPLACE POWER SEAT MOTOR ASSY 
    2. OK: REPAIR OR REPLACE HARNESS AND CONNECTOR 
  8. READ VALUE OF LEXUS HAND-HELD TESTER 
    1. Connect the LEXUS hand-held tester to the DLC3.
    2. Read DATA MONITOR Using hand-held tester.

      SEAT ECU 

      LEXUS HAND-HELD TESTER CHART

      Item Condition Standard value
      SLIDE SW FRONT SLIDE SEAT SW CENTER --> FRONT ON / OFF
      SLIDE SW REAR SLIDE SEAT SW CENTER --> REAR ON / OFF
      R VTCL SW UP REAR SW CENTER --> UP ON / OFF
      R VTCL SW DOWN REAR SW CENTER --> DOWN ON / OFF
      F VTCL SW UP REAR SW CENTER --> UP ON / OFF
      F VTCL SW DOWN REAR SW CENTER --> DOWN ON / OFF
      RECLIN SW FRONT RECLINING SW CENTER --> FRONT ON / OFF
      RECLIN SW REAR RECLINING SW CENTER --> REAR ON / OFF
    3. When only the "lumbar support" has a malfunction, proceed to "A".
    4. When no malfunction exists in all the items or all the items except the "lumbar support", proceed to "B".
    1. B: REPLACE FRONT POWER SEAT SWITCH RH 
    2. A: GO TO NEXT STEP. 
  9. INSPECT LUMBAR FRONT POWER SEAT SWITCH 
    1. Inspect the front power seat switch continuity.

    Lumbar switch: 

    TESTER CONNECTION CHART

    Switch position Tester connection Specified condition
    FRONT 1 <--> 3 1 <--> 4 Continuity
    BACK 2 <--> 3 2 <--> 4 Continuity
    Fig 5: Inspecting Front Power Seat Switch Continuity
    G03386947Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPLACE FRONT POWER SEAT SWITCH LH 
    2. OK: REPAIR OR REPLACE HARNESS AND CONNECTOR 
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