2001 Lexus IS 300FACTORY OEM SERVICE PROCEDURE

System Tests: Notes

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

Symptom & Description Perform Test No.
Auto Turn Off Does Not Operate
Driver's Door Courtesy Switch Circuit 10 
Ignition Switch 2 
Body ECU (1)
Theft Deterrent ECU (2)
(1) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
(2) See ANTI-THEFT SYSTEMS - IS300 article.
SYMPTOM INDEX (DOOR LOCK CONTROL SYSTEM)

Symptom & Description Perform Test No.
Lock Or Unlock Cannot Be Operated With Door Lock Control Switch
Door Lock Control Switch 20 
Power Window Master Switch 16 
Body ECU (1)
Door Key Linked Function Does Not Operate
Door Key Lock & Unlock Switch Circuit 15 
Power Window Master Switch 16 
Body ECU (1)
Key Confinement Prevention Function Does Not Operate
Key Unlock Switch Circuit 7 
Power Window Master Switch 16 
Body ECU (1)
(1) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
SYMPTOM INDEX (WIRELESS DOOR LOCK CONTROL SYSTEM)

Symptom & Description Perform Test No.
Wireless Door Lock Control System Does Not Operate
Wireless Door Lock Transmitter (1)
Key Unlock Warning Switch Circuit 7 
Wireless Door Lock ECU (2)
Body ECU -
Lock Or Unlock Function Does Not Operate
Door Key Lock & Unlock Switch Circuit 15 
Door Unlock Detection Switch Circuit 14 
Body ECU (3)
Automatic Lock Function Operates Even If Any Door Is Opened Within 30 Seconds After All Doors Are Unlocked By Wireless Door Lock Control System
Door Courtesy Switch Circuit (1)
Body ECU (3)
(1) Check transmitter operation.
(2) See POWER DOOR LOCKS, TRUNK LID & FUEL DOOR - IS300 article.
(3) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
SYMPTOM INDEX (OTHERS)

Symptom & Description Perform Test No.
Illuminated Entry Does Not Operate
Illumination Circuit 4 
Body ECU (1)
Key Remainder System Does Not Operate
Key Unlock Warning Switch Circuit 7 
Body ECU (1)
Seat Belt Warning Does Not Operate
Driver Buckle Switch Circuit 8 
Body ECU (1)
Instrument Cluster (2)
(1) Perform appropriate pin voltage test under BODY CONTROL ECU PIN VOLTAGE TESTS  under COMPONENT TESTS.
(2) See INSTRUMENT PANELS - IS300 article.
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.