Skip the auto shop - Our mechanics make house calls

Q: Check engine light on due to gas cap.

asked by on

Hello. I am having an issue with my check engine light. I went to Autozone to have a computer diagnositic check, and they said it was the gas cap. Bought a new gas cap, went off for a bit, then came back on. I went back, they told me to tighten it and drive and it would reset itself. I drove from NY to CT and back and it is still on. Not sure what to do and I have inspection coming up. What is the average price to fix something like this?

My car has 93000 miles.
My car has an automatic transmission.

You should have your fuel vapor control system for leaks by a mechanic that can fill the system with smoke from a smoke machine that helps to locate the leak in the system. The purge control valve is the most common cause of a leak in the system next to the gas cap. After running these tests, the technician should be able to find what needs to be repaired and estimate the cost to fix it.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Sometimes my car has issues starting

Hello there, a car that starts only after it sits overnight is a common fault. The fact that it starts after it sits for a long while tells me one or more component is on its way to failing but...

Q: Check engine light on - 2005 Mercedes-Benz SLK350

Have a mechanic check the code(s), then diagnose the vehicle based on that information. The problem setting the Check Engine Light may be doing other, unseen and expensive damage. A YourMechanic professional can help diagnose this issue by giving your...

Q: Where is the fuel tank pressure sensor in my car?

The fuel tank pressure sensor is located in the top of the fuel tank. The fuel tank will need to be removed to replace the sensor. The fuel tank sensor is not very common to go bad on this car....

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...