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.
Engine Controls - System/Component Tests: Introduction
Prior to testing separate components or systems, it is recommended that all procedures listed in BASIC TESTING article in the ENGINE PERFORMANCE Section. Since many computer controlled and monitored components will set a service code if they malfunction, check EEC-IV system and retrieve service codes. See Quick Test procedure in TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service codes are present see appropriate CIRCUIT TEST in TESTS W/CODES article in the ENGINE PERFORMANCE Section.
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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.
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