I have several check engine codes that i have my mechanic...


I have several check engine codes that i have my mechanic keep checking. He said it was the gas cap but it came back again. Then he said it was the fuel tank pressure sensor. It came back again and I think he is throwing me for a ...

I have several check engine codes that i have my mechanic keep checking. He said it was the gas cap but it came back again. Then he said it was the fuel tank pressure sensor. It came back again and I think he is throwing me for a loop so I checked the codes myself. It's a P0451 and p0455 code. What is wrong? I need to pass inspection it was due last month! Mechanic's Assistant: Are you certain it's the fuel pressure sensor that's in need of attention? What about the fuel rail? Have you checked it yet? He said he replaced the sensor but the code came back. I don't know about the fuel rail Mechanic's Assistant: What is the make/model/year of your car? Hyundai sonata 2011 or 2012 I keep forgetting sorry Mechanic's Assistant: Are you fixing your Sonata yourself? What have you tried so far? I gave it to the guy that sold me the car, whose my mechanic, but he hasn't fixed it yet. All I tried doing was using a computer to clear the codes. Mechanic's Assistant: Anything else you want the Mechanic to know before I connect you? Yeah it has 160k miles on it but still in excellent condition other than the check engine that keeps coming up

Automotive Expert
Hello and welcome to JustAnswer, my name is \*\*\*\*\* \*\*\*\*\* I have over 22 years of experience in this field. I'm so sorry for your inconvenience and hopefully, I can help. The codes you are getting from your vehicle is letting you know you have an Evap leak somewhere. You would need to do a smoke test on your vehicle to see where the leak is. The most common cause is the gas cap, but since he replaced that already it will need to be smoked.

What do I need to do to perform a smoke test?
Automotive Expert
Is a special machine that puts in smoke in your Evap system so you can see the leak. The Evap system is supposed to be a sealed system, if it is leaking any small amount of air it will trigger a light. Your local auto mechanic shop should have one if not you would need to go to your local Hyundai dealer.

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