System Operation Check

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

Trouble shooting of a power seat system complaint begins with verification of the customer problem. Perform the Customer Problem Analysis Check (Power Seat Control System). See Fig 1.

Determine and confirm symptom. See POWER SEAT PROBLEM SYMPTOMS . Without applicable symptoms, go to step 3. With applicable symptoms, go to step 4.

POWER SEAT PROBLEM SYMPTOMS

Symptom

Suspected Area

Both Manual & Return Functions Do Not Operate (All Functions)

Power Source Circuit ⁽¹⁾, Power Seat Control Switch Circuit ⁽²⁾, Seat Position Control ECU ⁽³⁾ Or Wiring Harness

Both Manual & Return Functions Do Not Operate (One Function Only)

Motor Circuit ⁽⁴⁾, Seat Position Control ECU ⁽³⁾, Seat Position Motor ⁽⁵⁾Or Wiring Harness

One Or All Functions Do Not Operate For Manual Operation Only

Power Seat Control Switch Circuit ⁽²⁾, Seat Position Control ECU ⁽³⁾ Or Wiring Harness

Memory Function Does Not Operate

Power Seat Memory Switch Circuit ⁽⁶⁾, Ignition Switch Circuit, Park/Neutral Position Switch Circuit ⁽⁷⁾, Seat Position Control ECU Or Wiring Harness

Only Return Function Does Not Operate Or Operates A Little, Then Stops (All Return Functions)

Seat Position Control ECU ⁽³⁾

Only Return Function Does Not Operate Or Operates A Little, Then Stops (Only One Return Function)

Seat Position Control ECU ⁽³⁾ Or Power Seat Motor ⁽⁵⁾

Power Seat Does Not Operate

Front Power Seat Switch ⁽⁵⁾, PWR SEAT Fuse Or Wiring Harness

Power Seat Does Not Slide

Front Power Seat Switch ⁽⁵⁾, Front Slide Power Seat Motor Assembly (Slide) ⁽⁵⁾ Or Wiring Harness

Front Vertical Of Power Seat Does Not Operate (Driver's Seat Only)

Front Power Seat Switch ⁽⁵⁾, Front Up/Down Power Seat Motor Assembly (Front Vertical) ⁽⁵⁾ Or Wiring Harness

Rear Lifter Of Power Seat Does Not Operate (Driver's Seat Only)

Front Power Seat Switch ⁽⁵⁾, Power Seat Motor Assembly (Rear Vertical) ⁽⁵⁾ Or Wiring Harness

Power Seat Does Not Recline

Front Power Seat Switch ⁽⁵⁾, Power Seat Motor Assembly (Reclining) ⁽⁵⁾ Or Wiring Harness

Lumbar Support Does Not Operate (Driver's Seat Only)

Front Power Seat Switch ⁽⁵⁾, Power Seat Motor Assembly (Lumbar Support) ⁽⁵⁾ Or Wiring Harness

Seat Heaters Do Not Operate

SEAT HTR 20A Fuse, Front Seat Cushion Heater Assembly ⁽⁸⁾, Front Seat Back Heater Assembly ⁽⁸⁾, Heater Control Housing Sub-Assembly (A/C Amplifier) ⁽⁹⁾ Or Wiring Harness

⁽¹⁾	See POWER SOURCE CIRCUIT under COMPONENT TESTS.

⁽²⁾	See POWER SEAT CONTROL SWITCH CIRCUIT under COMPONENT TESTS.

⁽³⁾	Inspect connector, check for open or short circuit, and check and replace ECU.

⁽⁴⁾	See POWER SEAT MOTOR CIRCUIT under COMPONENT TESTS.

⁽⁵⁾	See POWER SEAT INSPECTION under COMPONENT TESTS.

⁽⁶⁾	See MEMORY SWITCH CIRCUIT under COMPONENT TESTS.

⁽⁷⁾	See DIAGNOSIS - U150E under AUTOMATIC TRANSMISSION article in TRANSAXLE/TRANSMISSION.

⁽⁸⁾	See SEAT HEATER INSPECTION under COMPONENT TESTS.

⁽⁹⁾	See DTC 63: SEAT HEATER CIRCUIT (DRIVER SIDE) or DTC 64: SEAT HEATER CIRCUIT (PASSENGER SIDE) under DIAGNOSTIC TESTS.

Perform trouble shooting in the following method, depending on the malfunction symptom.
- Terminal Of ECU. See TERMINALS OF ECU under COMPONENT TESTS.
- On-Vehicle Inspection. See ON-VEHICLE INSPECTION (WITH MEMORY) .
- Inspection. For memory seat switch inspection, see step 1 of MEMORY SWITCH CIRCUIT under COMPONENT TESTS. For power seat inspection, see ON-VEHICLE INSPECTION (POWER SEAT OPERATION) .
Perform necessary adjustments, repairs or replacements.
Perform a confirmation test. See CONFIRMATION TEST .

Fig 1: Customer Problem Analysis Check (Power Seat Control System)