Warning lights

Check fuel cap warning light

This message means the evaporative emissions system has detected a possible leak, almost always because the fuel cap isn't sealed properly.

Difficulty
Easy
Time
5–15 minutes
DIY cost
$0–$20
Pro cost
$20–$60

Symptoms

  • 'Check fuel cap' message or icon on the dash
  • Car drives normally
  • Often follows a recent fill-up

Likely causes

  • CommonGas cap not fully tightenedMost caps need to click several times to seal completely.
  • CommonWorn or cracked gas cap sealRubber seals dry out over years of sun and heat exposure.
  • PossibleGas cap missing or wrong replacement cap usedAn aftermarket cap that doesn't seal correctly can trigger this.

What to do

  1. Pull over safely and check that the gas cap is present.
  2. Tighten the cap until it clicks several times or stops turning.
  3. Inspect the rubber seal for cracks, stiffness, or debris.
  4. Replace the cap if the seal looks worn or damaged.
  5. Drive normally for a few trips; the light often needs several drive cycles to clear on its own.
  6. Have the code read if the message persists after confirming the cap is tight and undamaged.

Tools and parts

Gas capSearch: “OEM-fit gas cap for your car”

When to call a pro

See a mechanic only if the message doesn't clear after a week of driving with a confirmed tight, undamaged cap.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.