At 800 miles my check engine light has come on about 50 miles and 3 days from last fill up. Last Fill up was full serve... So it might be a not fully tightened cap? Seemed tight but I opened and retightned it. but would it take that long to come up with error? 7-8 mile short hops. Light came on right at startup. If it is the cap how long will it take to clear? How long before I take back to dealer.... who charges $45 for such non - warrenty work.
The evap. test would need to run 3 times on separate trips with no failures to turn the lamp out. This test may or may not run each time you drive the vehicle. To my knowledge, Hyundai hasn't published the requirements for the test to run.
You may want to take your car to autozone or anywhere else that will scan it for free. The time for the lamp to come on is about right for a fuel cap issue. Sometimes it's on tightly but crossthreaded, so the seal won't hit the filler neck. If you have a code P0455, P0442, or P0456, you would be okay to presume it was probably a fueling issue and reset the lamp to see if it returns.
Also, make sure when receiving full service that the attendant doesn't continue pumping significantly after fuel shut-off. This can cause fuel to get into the charcoal canister and ruin it. If that's the case, I'd expect a code P0449 or one of the others above. If you have a P0449, you should take the car to be diagnosed.
Your check engine light came on because the GAS CAP isn't secured. What I do is turn teh cap at least two to three full revolutions. I too had teh engine light come on and it took up to a week to go off. You don't want to unscrew it and retighten it because it already has air in the system As long as the car doesn't idle rough or stall that would be a sign of a bad oxygen sensor. If you continually have this problem, then the simplist way to fix it would be to puchash a new HYNDAI GAS CAP NOT A STORE BOUGHT WILL FIT YOU CAR TYPE. Must be Hyundai
Cleared it in about 30 miles after opening and retightening. 10 miles then
20 mile runs. It seems to test at startup... after 2 runs I turned engine off 1 min And restarted... Cleared the light.MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.