2001 Lexus GS 300FACTORY OEM SERVICE PROCEDURE

System Tests: Notes

NOTE: If LEXUS scan tool is available for the following circuit tests, connect scan tool to Data Link Connector 3 (DLC3) located under left side of instrument panel.
SYMPTOM INDEX (DOOR LOCK CONTROL)

Symptom & Description Perform Test No.
Lock Or Unlock Cannot Be Operated With Door Lock Control Switch
Driver's Door Lock Control Switch Circuit 5 
Passenger's Door Lock Control Switch Circuit 27 
Driver's Door ECU, Body Control ECU No. 1 (1)
Door Key Link Function Does Not Operate
Driver's Door Key Lock & Unlock Switch Circuit 5 
Passenger's Door Key Lock & Unlock Switch Circuit 27 
Driver's Or Passenger's Door ECU (1)
Body Control ECU No. 1 (2)
Key Confinement Prevention Function Does Not Operate
Key Unlock Warning Switch Circuit 7 
Body Control ECU No. 1, Body Control ECU No. 2 (2)
System Does Not Lock & Unlock Each Door Individually
Driver's Door Lock Motor Circuit 6 
Left Rear Door Lock Motor Circuit 18 
Passenger's Door Lock Motor Circuit 28 
Right Rear Door Lock Motor Circuit 33 
Driver's Or Passenger's Door ECU, Left Or Right Rear Door ECU (1)
Luggage Compartment Opening Function Does Not Operate
Luggage Compartment Door Opener Switch Circuit 24 
Body Control ECU No. 1 (2)
(1) See appropriate wiring diagram in POWER DOOR LOCKS, TRUNK LID & FUEL DOOR - GS300 & GS430 article.
(2) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
SYMPTOM INDEX (WIRELESS DOOR LOCK CONTROL SYSTEM) (3)

Symptom & Description Perform Test No.
Wireless Door Lock Control System Does Not Operate
Wireless Door Lock Transmitter (1)
Key Unlock Warning Switch Circuit 16 
Wireless Door Lock Tuner Circuit 38 
Body Control ECU No. 1, Body Control ECU No. 2 (2)
Lock Or Unlock Function Does Not Operate
Driver's Door Key Lock & Unlock Switch Circuit 5 
Driver's Door Unlock Detection Switch Circuit 7 
Left Rear Door Unlock Detection Switch Circuit 19 
Passenger's Door Key Lock & Unlock Switch Circuit 26 
Passenger's Door Unlock Detection Switch Circuit 29 
Right Rear Door Unlock Detection Switch Circuit 34 
Driver's Or Passenger's Door ECU, Left Or Right Rear Door ECU, Body Control ECU No. 1 (2)
Auto Lock Function Operates When Any Door Is Opened Within 30 Seconds After Unlocking All Doors With Wireless Door Lock Control System
Driver's Door Courtesy Light & Courtesy Switch Circuit 4 
Left Rear Door Courtesy Light & Courtesy Switch Circuit 17 
Passenger's Door Courtesy Light & Courtesy Switch Circuit 25 
Right Rear Door Courtesy Light & Courtesy Switch Circuit 32 
Driver's Or Passenger's Door ECU, Left Or Right Rear Door ECU, Body Control ECU No. 1 (2)
Wireless Door Lock Operates, But Buzzer Does Not Sound
Wireless Door Lock Buzzer Circuit 37 
Body Control ECU No. 1 (2)
Buzzer Sounds, But Wireless Door Lock Function Does Not Operate
Body Control ECU No. 1 (2) 37 
Luggage Compartment Door Opener Does Not Operate Properly
Luggage Compartment Door Opener Motor Circuit 23 
Body Control ECU No. 1 (2)
(1) Check transmitter operation.
(2) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
(3) See appropriate wiring diagram in POWER DOOR LOCKS, TRUNK LID & FUEL DOOR - GS300 & GS430 article.
SYMPTOM INDEX (ANTI-THEFT SYSTEM)

Symptom & Description Perform Test No.
System Cannot Be Set
Anti-Theft Indicator Circuit 2 
Driver's Door Courtesy Light & Courtesy Switch Circuit 4 
Driver's Door Unlock Detection Switch Circuit 7 
Engine Hood Courtesy Switch Circuit 11 
Key Unlock Warning Switch Circuit 16 
Left Door Courtesy Light & Courtesy Switch Circuit 17 
Left Rear Door Unlock Detection Switch Circuit 19 
Luggage Compartment Door Courtesy Switch Circuit 21 
Passenger's Door Courtesy Light & Courtesy Switch Circuit 25 
Passenger's Door Unlock Detection Switch Circuit 29 
Right Rear Door Courtesy Light & Courtesy Switch Circuit 32 
Right Rear Door Unlock Detection Switch Circuit 34 
Driver's Or Passenger's Door ECU (1)
Left Or Right Rear Door ECU (2)
Body Control ECU No. 1, Body Control ECU No. 2 (2)
System Cannot Be Canceled When Ignition Is In ON Position
Key Unlock Warning Switch Circuit 16 
Ignition Switch Circuit (3)
Body Control ECU No. 1, Body Control ECU No. 2 (2)
System Does Not Cancel When Luggage Compartment Door Is Opened With Key
Luggage Compartment Door Key Lock & Unlock Switch Circuit 22 
Body Control ECU No. 1 (2)
Headlights Do Not Operate Properly With System
Headlight Relay Circuit 14 
Body Control ECU No. 1, Body Control ECU No. 2 (2)
Taillights Do Not Operate Properly With System
Taillight Relay Circuit 36 
Body Control ECU No. 1, Body Control ECU No. 2 (2)
Hazards Do Not Operate Properly With System
Hazard Switch Circuit 12 
Body Control ECU No. 1 (2)
Anti-Theft Horn & Standard Horn Does Not Sound
Anti-Theft Horn Circuit 1 
Standard Horn Circuit 35 
Body Control ECU No. 1 (2)
During Warning Condition, System Cannot Be Canceled By Unlocking Door With Key
Driver's Door Key Lock & Unlock Switch Circuit 5 
Passenger's Door Key Lock & Unlock Switch Circuit 26 
Driver's Or Passenger's Door ECU, Body Control ECU No. 1 (2)
During Warning Condition, System Cannot Be Canceled By Unlocking Door With Transmitter
Wireless Door Lock Transmitter (4)
Wireless Door Lock Tuner Circuit 38 
Body Control ECU No. 1 (2)
During Warning Condition, System Cannot Be Canceled By Turning Ignition To ACC Or ON Using Key
Ignition Switch Circuit (3)
Key Unlock Warning Switch Circuit 16 
Body Control ECU No. 1, Body Control ECU No. 2 (2)
Horns Sounded For More Than 60 Seconds
Body Control ECU No. 1 (2)
(1) See appropriate wiring diagram in POWER DOOR LOCKS, TRUNK LID & FUEL DOOR - GS300 & GS430 article.
(2) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
(3) Check ignition switch. See STEERING COLUMN SWITCHES article.
(4) Check transmitter operation.
SYMPTOM INDEX (LIGHT CONTROL SYSTEM)

Symptom & Description Perform Test No.
Automatic Light Control Does Not Operate
Headlight Control Switch Circuit, 13 
Light Sensor Circuit 20 
Body Control ECU No. 2 (1)
Automatic Turn Off Does Not Operate
Driver's Door Courtesy Switch Circuit 4 
Ignition Switch Circuit (2)
Driver's Door ECU (3)
Body Control ECU No. 2 (1)
(1) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
(2) Check ignition switch. See STEERING COLUMN SWITCHES article.
(3) See appropriate wiring diagram in POWER DOOR LOCKS, TRUNK LID & FUEL DOOR - GS300 & GS430 article.
SYMPTOM INDEX (ILLUMINATED ENTRY CONTROL SYSTEM)

Symptom & Description Perform Test No.
Illuminated Entry Does Not Operate Properly
Illumination Circuit 15 
Body Control ECU No. 2 (1)
(1) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
SYMPTOM INDEX (MISCELLANEOUS)

Symptom & Description Perform Test No.
Driver's Seat Belt Warning Indicator Does Not Turn Off
Driver's Seat Belt Buckle Switch Circuit 8 
Body Control ECU No. 2 (1)
Passenger's Seat Belt Warning Indicator Does Not Turn Off
Passenger's Seat Belt Buckle Switch Circuit 30 
Body Control ECU No. 1 (1)
Clock Light Will Not Dim
Clock Circuit 3 
Body Control ECU No. 2 (1)
Rear Window Defogger Does Not Operate
Defogger Relay Circuit 31 
Defogger Switch (2)
Body Control ECU No. 1 (1)
Body Control ECU No. 1 Does Not Operate
ECU Power Source Circuit No. 1 9 
Body Control ECU No. 1 (1)
Body Control ECU No. 2 Does Not Operate
ECU Power Source Circuit No. 2 10 
Body Control ECU No. 2 (1)
(1) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
(2) Check defogger switch. See appropriate wiring diagram in REAR WINDOW & SIDE MIRROR DEFOGGERS article.
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