Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnosis & Repair (Using Lexus Scan Tool)
2004 Toyota Celica GT, StandardSECTION Diagnosis & Repair (Using Lexus Scan Tool)
WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
- Connect Lexus scan tool to Data Link Connector (DLC) No. 3. See Fig 1 and Fig 2 . Turn scan tool on. Turn ignition on. Using scan tool, read STA signal with ignition on and then while cranking starter.
- With ignition on, STA signal should be off. With ignition switch in START position, STA signal should be on. If STA signal is not as specified, go to next step. If STA signal is as specified, no problem is indicated at this time. Diagnose by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES article.
- Check for open in wiring harness between ECM and starter relay. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary. If wiring is okay, replace ECM and retest.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.