Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

READ VALUE OF HAND-HELD TESTER
1. Connect the hand-held tester (with CAN VIM) to the DLC3.
2. Turn the ignition switch ON and press the hand-held tester main switch ON.
3. Select the items below in the DATA LIST, and read the hand-held tester's screen.
4. Watch the hand-held tester screen while adjusting the seat with the power seat control switches. Check that the position sensor value changes.
5. Watch the hand-held tester screen while adjusting the seat with the power seat control switches. Check that the motor status changes from STANDBY to MOVING.
HINT:

When the seat is at an extreme position (for example, seatback position fully forward or sliding position fully rearward) and the power seat control switch is held down, the motor status should read LOCK. When the switch is released, the motor status should change to STANDBY.

Driver seat ECU:

Fig 1: Driver Seat ECU - Measurement Condition Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step.

Position sensor values should vary within the minimum and maximum values shown in the chart above.

For the tester's motor status item, the display should changes between STANDBY, MOVING and LOCK according to the chart above.

NG: Go to step 2

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE (See PROBLEM SYMPTOMS TABLE )
CHECK WIRE HARNESS (DRIVER SEAT ECU - POWER SEAT SENSOR AND BODY GROUND)
1. Disconnect the D27 and D28 ECU connectors.
2. Disconnect the P40, P41, P42, P43, P44 and P45 sensor connectors.
3. Measure the resistance of the wire harness side connectors.
  Standard:
  
  Fig 2: Terminals Resistance Reference Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 3: Checking Wire Harness (Driver Seat ECU - Power Seat Sensor And Body Ground)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

OK: Go to next step.
CHECK DRIVER SEAT ECU (SENSOR POWER SOURCE VOLTAGE)
1. Turn the ignition switch ON.
2. Measure the voltage of the ECU connector.
  Standard:
  
  Fig 4: Terminals Voltage Reference Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 5: Checking Driver Seat ECU (Sensor Power Source Voltage)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE DRIVER SEAT ECU

OK: Go to next step.
CHECK POWER SEAT POSITION SENSOR
1. Turn the ignition switch ON.
2. Measure the voltage of the ECU connector.
  Standard:
  
  Fig 6: Terminals Voltage Reference Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 7: Checking Power Seat Position Sensor
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
HINT:

Check the power seat position sensors that are malfunctioning.

Run the motors and check that the voltage readings vary within the "specified condition" shown in the chart above.

*:If the result is not as specified proceed to steps indicated in this column.

A: REPLACE FRONT SEAT HEADREST ADJUSTER

B: REPLACE POWER SEAT ADJUSTER

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE (See PROBLEM SYMPTOMS TABLE )