Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If not using the hand-held tester, begin with step 2.

Check the power seat control switch operation. Connect the hand-held tester to the DLC3. See Figure. Turn the ignition switch ON and the hand-held tester main switch ON. Select the ACTIVE TEST mode on the hand-held tester. Check that the switch status (ON/OFF) changes on the screen of the hand-held tester as the power seat control switch of the vehicle is turned. If the switch status changes in the same way as the vehicle switch operation, check and replace the power seat position ECU. If the results are not as specified, go to the next step.

Check the power seat control switch. Remove the seat. See FRONT SEAT under REMOVAL & INSTALLATION. Disconnect the power seat control switch. Check the continuity between terminals when the switch is operated. See CONNECTOR IDENTIFICATION . See INSPECTING POWER SEAT CONTROL SWITCH CONTINUITY table.

INSPECTING POWER SEAT CONTROL SWITCH CONTINUITY

Switch Position	Tester Connection	Specified Condition
Slide Switch
FRONT	1 - 9	Continuity
BACK	1 - 6	Continuity
Front Vertical Switch (Driver)
UP	1 - 5	Continuity
DOWN	1 - 10	Continuity
Front Vertical Switch (Passenger)
UP	1 - 10	Continuity
DOWN	1 - 5	Continuity
Lifter Switch (Driver)
UP	1 - 8	Continuity
DOWN	1 - 7	Continuity
Lifter Switch (Passenger)
UP	1 - 7	Continuity
DOWN	1 - 8	Continuity
Reclining Switch
FRONT	1 - 3	Continuity
BACK	1 - 2	Continuity

Check the wiring harness and connectors between power seat position ECU and power seat control switch. If the results are OK, check and replace the power seat position ECU. If the results are not OK repair and replace the wiring harness or connector.