Use a code as a starting point for diagnosis. Record the complete code, symptoms and freeze-frame data before clearing anything or buying parts.
Start here
- How to scan your Check Engine Light at home
- Ignition and spark-plug guides
- Ask a question for your vehicle
What to include in a diagnostic question
- Year, make, model, engine and mileage.
- Exact codes, including stored, pending and permanent status if shown.
- Whether the light is steady or flashing and when the symptoms happen.
- Recent repairs and the checks already performed. Do not post a full VIN or personal details.
Flashing light or severe symptoms?
A flashing check-engine light can indicate a severe misfire. Reduce load and arrange prompt help. Stop safely if the vehicle shakes badly, overheats, loses oil pressure or is unsafe to drive. Follow your owner’s manual.
Reference: EPA guidance on onboard diagnostics and the check-engine light.