Skip the auto shop - Our mechanics make house calls

Q: check engine light

asked by on

Hi, a few months ago a check engine light came on my Hyundai. Firestone ran diagnostic codes and replaced canister purge valve, vent shut valve and intake hose assembly. After about a month check engine light came on again, they ran the codes and replaced my fuel cap. Again the car was fine for a month or so and the light came on again. They ran the codes again and they said i have a faulty fuel tank pressure sensor and replaced that. That was last week and today the light came on again! Before I take it back to the shop I was hoping to figure out of they are just ripping me off by having me replace all these parts or is it really possible that all these parts are failing in such rapid succession? It seems incredible to me that all of these parts need replacing. Is it possible they are misdiagnosing the problem? Is it possible i just have a faulty check engine light sensor? I am also considering buying my own code reader (they are about $15 on Amazon). Is that worth it? Thanks! Leeka
My car has an automatic transmission.

These are all parts related to the fuel tank which indirectly relate to the pressurization of the tank. The canister purge valve is something that allows excess pressure to be removed from the tank. The vent shut valve and intake hose assembly is the actual intake tube that moves the fuel to the tank when you are pumping the fuel into your tank at the pump. As you know the fuel cap maintains pressure when it is sealed correctly. Finally, the fuel tank pressure sensor is a sensor that relays the fuel tank pressure in pounds per square inch (PSI) to the car’s computer. These components all work together to maintain a specific fuel pressure in order to supply the fuel injection system in your car properly. Without sufficient fuel pressure, the intake would not work properly. Although, it is coincidental that each of these parts failed successively, it is not entirely unreasonable as they all work together and respond to each other indirectly. A faulty check engine light sensor is highly unlikely as this is simply a reflection of what the computer reads. Yet, if you would like, a certified technician from YourMechanic can come to your home or office to diagnose your Check Engine Light issue.

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!
  1. Home
  2. Questions
  3. check engine light

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: My Check Engine light came on and now I'm having problems with the motor oil, it leaks. 2007 Kia Spectra

Hello - the first task is to see what problem codes are set, causing the Check Engine light to come on. Check oil level as well. Hopefully, the oil leak is not the root cause of the Check Engine situation....

Q: How do I adjust the electric side view mirrors?

The side view mirrors provide important visibility to you when you are driving. Before driving, you should always adjust the side view mirrors so that you have maximum visibility. The electric side view mirrors are controlled with the Mirror switch,...

Q: found a patch of transmission fluid on the ground burning smell below my radiator

Hello, thank you for writing in. The vehicle is likely experiencing a leak or other malfunction with the cooling system. It is difficult to say without performing an inspection, but you can perform a basic one just by visually looking...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.