Power Windows: Diagnosis Lexus GS II

TROUBLE SHOOTING

Note. Before proceeding with trouble shooting, check multiplex system for faults. See MULTIPLEX CONTROL SYSTEMS article. If no faults are found in multiplex system, proceed with TROUBLE SHOOTING.

Ensure all component terminals and ground connections are clean and tight. Check possible faults in order listed. Repair or replace components and/or circuits as necessary.

TEST A: SINGLE WINDOW DOES NOT OPERATE

Note. Codes retrieved without a scan tool are listed as 2-digit codes. Codes retrieved with a scan tool have a B12 prefix (example: B1225 = code 25).

1. Check For DTCs Using scan tool, check for DTC B1221, B1222, B1223, B1224, B1225 or B1226. If DTC's listed are present, go to next step. If DTC's listed are not present and driver door window is inoperative, go to step 6. If DTC's listed are not present and any passenger door window is inoperative, go to step 5.
2. Check Door Lock Operation Check to see if door lock in same door as inoperative window operates. If door lock operates properly, go to next step. If door lock does not operate properly, check for blown fuse, shorted or open wires. See WIRING DIAGRAMS. Repair or replace as necessary and retest system operation.
3. Check Circuits Disconnect driver door ECU connectors. Using an ohmmeter, check resistance between driver door ECU connector "A" terminal No. 2 and driver door ECU connector "C" terminal No. 12. Check resistance between driver door ECU connector "A" terminal No. 11 and driver door ECU connector "C" terminal No. 12. (Scheme 1) If both resistance readings are less than 5 ohms, go to next step. If either resistance reading is 5 ohms or more, replace driver door ECU and retest system operation.
4. Check Power Window Motor Disconnect inoperative window motor connector. Connect positive battery lead to window motor connector terminal No. 2 for front window motors and No. 3 for rear window motors and negative lead to terminal No. 1. (Scheme 2) If power window motor operates properly, go to step 7. If power window motor does not operate properly, check power window motor wiring harness and connector. If wiring and connector are okay, replace power window motor and retest system operation.
5. Check For Power To Passenger Power Window Switch Disconnect passenger window switch connector. Turn ignition switch to ON position. Using a voltmeter, check voltage at passenger window switch connector terminal No. 3 (Yellow/Red wire). If 10-14 volts is present, go to next step. If 10-14 volts is not present, repair or replace wiring harness. See WIRING DIAGRAMS.
6. Check Circuits Check continuity of circuits between appropriate window switch and appropriate door ECU (for inoperative window). See WIRING DIAGRAMS. If circuits are okay, go to next step. Repair or replace circuits as necessary. Retest system operation.
7. Replace Driver Door ECU Replace original driver door ECU with known-good unit. Retest system operation. If system operates properly, original driver door ECU was faulty. If system still does not operate properly, return to step 1).

Scheme 1

Scheme 2

THEFT DETERRENT ECU TEST

For testing procedures, see appropriate ANTI-THEFT SYSTEM article.

DOOR OPEN DETECTION SWITCH TEST

For testing procedures, see appropriate ANTI-THEFT SYSTEM article.

WINDOW MOTOR TEST

1. Disconnect window motor connector. Apply battery voltage between motor connector terminals. Motor should operate. To reverse motor direction, reverse polarity of voltage to motor. Replace motor if it does not operate.
2. If application of battery voltage to motor continues after window has stopped moving, a circuit breaker in motor should open in 4-40 seconds and motor should stop. After circuit breaker opens, reverse polarity of voltage to motor.
3. Within 60 seconds, motor should move in opposite direction, indicating circuit breaker has closed. Replace motor as necessary.

POWER MAIN RELAY TEST

Remove relay. See ELECTRICAL COMPONENT LOCATIONS table under DESCRIPTION & OPERATION. (Scheme 3) Replace relay if it does not operate as follows

1. Continuity constant between terminals No. 1 and 2.
2. No continuity should exist between terminals No. 3 and 5.
3. Apply battery voltage and ground between terminals No. 1 and 2. Continuity should exist between terminals No. 3 and 5.

Scheme 3

MASTER SWITCH TEST

Remove master switch. Check for continuity between specified terminals of master switch. (Scheme 4) See MASTER SWITCH CONTINUITY TEST table. If continuity is not as specified, replace master switch.

MASTER SWITCH CONTINUITY TEST

Scheme 4

PASSENGER'S SWITCH TEST

Remove passenger's switch. Check for continuity between specified terminals of passenger's switch. (Scheme 5) See PASSENGER'S SWITCH CONTINUITY TEST table. If continuity is not as specified, replace passenger's switch.

PASSENGER'S SWITCH CONTINUITY TEST

Scheme 5