Keep Your Gas Cap Tight and Sealed

The Problem

Your check engine light is on. It might just be a loose gas cap.

The Hack

After filling up, click the gas cap until it clicks at least 3 times. If your check engine light is on, try tightening the cap and driving for a day — it often clears the light.

Why It Works

A loose gas cap allows fuel vapors to escape (the EVAP system detects this and triggers the check engine light). Fuel evaporation wastes gas and releases pollutants.

Pro Tips

• Click until you hear 3+ clicks after filling up
• A cracked or missing gas cap: replace for $5-10
• This is the #1 cause of check engine lights — try tightening first
• If cap is fine and light stays on, get codes read at AutoZone (free)