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.
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HOMESERVICE MANUALSTOYOTA2004CELICA GT, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 94 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTING)COMPUTERIZED ENGINE CONTROLSSTARTER SIGNAL CIRCUITDIAGNOSIS & REPAIR (USING OBD-II SCAN TOOL) - RX300
2004 Toyota Celica GT, Standard
Diagnosis & Repair (Using OBD-II Scan Tool) - RX300
2004 Toyota Celica GT, StandardSECTION Diagnosis & Repair (Using OBD-II Scan Tool) - RX300
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.
- Access ECM harness connectors behind glove box. Backprobing ECM harness connector, measure voltage between ground and terminal No. 9 (Black/Yellow wire) STA at ECM E9 connector. See Figure.
- Turn ignition switch to START position. With starter being cranked, voltage should be 6 volts or more. If voltage is not as specified, go to next step. If voltage 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.
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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.