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.
2003 Toyota Avalon XLSFACTORY OEM SERVICE PROCEDURE
Malfunction Indicator Light Inspection
NOTE:
The malfunction indicator light (MIL) may also be referred to as CHECK ENGINE light. Inspect MIL to ensure it is operational and will come on if a diagnostic trouble code (DTC) is set.
- The MIL comes on when the ignition switch is turned ON and the engine is not running. If the MIL does not light up, trouble shoot the combination meter. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.
- When the engine started, the MIL should go off. If the lamp remains on, the diagnosis system has detected a malfunction or abnormality in the system. See TESTING PROCEDURE .
Factory Service Tools
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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.