The 'Check Engine' Light does not turn off?


Asked by Jul 15, 2009 at 01:03 AM about the Hyundai Sonata

Question type: Maintenance & Repair

I have read every discussion on this page and thankfully my sonata runs good based on the reviews i read. the car is a well taken care of car but the check engine light stays on. it has been about 6 days and the light does not turn off. the engine and the fuse box are doing well. everything else is doing well. have had friends that work with vehicles and they say they do not know. i need an answer. my last place to go is to a dealership.

23 Answers


No one can help until you get someone to pull the codes the computer is reading in order for it to put the check engine light on.

7 out of 7 people think this is helpful.

Check the gas cap it is a common cause of the check engine light problem.

25 out of 25 people think this is helpful.

STOP using ethenol gas it causes poorer gas milage and resluts in the check engine light coming on. After two tank fulls of PURE gas ( non Ethenol ) the light went off!

9 out of 9 people think this is helpful.

Take it to the dealer. My 2011 elantra has been in 4 times for the check engine light. Thy replaced the o2 sensors, but the light still comes on. Hyundai corp is flyin in a tech, because they are apparently having widespread problems, primarily on the east coast. Dealer tried to tell me it was bad gas in the region, but I think that's a load of doodoo. Take it in.. Emissions system is warranted for 8 urs 80,000 miles!

8 out of 8 people think this is helpful.

Just have the codes read at autizone or something. The check engine light neans the computer thinks something is wrong. About 50% of codes do not create a driveability issue but is emissions control related.

10 out of 10 people think this is helpful.

FYI, I had the same problem (Sonata 2009) and had a dealer check it. They pulled the code, told me it was an evaporative system problem, and asked about refueling and the fuel cap. They reassured me, as I was in the middle of a nearly 3000 mile drive, that it wasn't critical. So, here's the thing. We were at around 6000 feet above sea level, in New Mexico. When we got to the Bay Area in San Francisco a few days later, guess what - the light went out on its own. Which suggests to me that it was to do with altitude and the changes in atmospheric pressure, and actually nothing was wrong at all.

7 out of 7 people think this is helpful.

I have a 2005 Sonata and have had issues over the years with the Check Engine light. Every time it was an evaporation leak and I got blamed on the gas cap. Recently it comes on more often and I changed the gas cap which did not solve the problem. The dealer is suggesting the Purge Valve replacement. Any thoughts on the forum?

28 out of 28 people think this is helpful.

I have had multiple check engine light problems with 2005 Hyundai Sonata. Car runs fine. replaced gas cap three times. Mechanic cleaned some things. Light still comes on after awhile. Mechanic suggested I ignore the check engine light because it will cost many hundreds to diagnose.

1 out of 1 people think this is helpful.

I had a similar problems with my Sonata which became persistent, The problem was my Purge Valve which I purchased on Amazon for $20.53 and replaced it myself. After that I have not had the problem. I also bought the Autel (MaxiScan MS309) OBD-II Code Reader / Scan Tool ($24.99) on Amazon to clear the check engine light. Hope this helps.

10 out of 10 people think this is helpful.

Could it possibly be the oil cap itself? I have a 2007 Sonata and the check engine light was on for years. I had a part changed from code readings (at this time, sorry to say I don't remember what it was). That didn't help. After my last oil change surprisingly the light went out. It came on a few times for a short time (maybe three days in a row) and then went out once again. I did have the codes done (when the light was on) and one of the things it could have been was something to do with the oil pressure. I have added oil in the past and just today I needed to. The cap was SO hard to open I had to use a wrench and a screwdriver. When I finally closed it, I used the wrench and screwdriver again, instead of my hand, and to my surprise after a couple of turns, it snapped closed. I tried to keep closing it but at that point it wouldn't budge. I've added oil in the past and never experienced this before and my check engine light was always on. I always just closed the oil cap with my hand, never to the point of it "snapping" closed. Hymmm....maybe this was why the light was always on. Maybe only the last oil change people knew how to close the caps on these cars. Anyone experience this?

5 out of 5 people think this is helpful.

There isn't a code for your oil cap, nor would it really cause any codes. Being off would be worse than too tight. If you gave us the specific code that would help. Oil pressure and oil level are 2 different things. If you run to low a level to the point oil pressure is effected you have damaged the engine. Mostly low oil pressure is due to worn oil pump or just a worn out motor. But without knowing the code I can't say much

3 out of 3 people think this is helpful.

I have to look for those codes!!

1 out of 1 people think this is helpful.


2 out of 2 people think this is helpful.

Don't know

1 out of 1 people think this is helpful.

No issues after replacing my Purge Valve a year ago. Please see my post above.

2 out of 2 people think this is helpful.

Never got the chech emgine light to go out. Been taken for over $1000+- by Hyundai deal er . Light always came back on within a few days after pickup from dealer. Ended up dumping the Hyundai shitmobile on Carmax.

2 out of 2 people think this is helpful.

Was the Purge Valve ever changed housing?

1 out of 1 people think this is helpful.

wow I just got one, the engine light is not on yet.. But I looked at car fax and it had so many vehicle serviced reports in the last 4 months.. So I squeezed it from the Hyundai dealer that the lady keep bringing in the car for engine light on, the said once in the shop the light was off, also did not mention anything about that the could read the codes.. trying to hide something??? So even a dealer reads the codes the can't fix it from reading those codes? I test drove another Sonata at a dealer, there the engine light went off but you could feel the engine is stalling when I push gas. Looks like every 2nd Sonata has that problem :( My 2004 Sonata run like new

I would be not surprised that people that try to safe few cents and put the cheap Arco gas and get the Engine light going on.. I did not have any light at my V6 2004 sontata but when put arco gas the car felt like loosing 20% power !


When my 2005 Sonata V6 was transported from Los Angeles,CA to Spring, TX in March of this year, the engine light came on. I cleared it myself and its been fine passing inspection. Not sure why it happened! The car runs well and we have postponed getting rid of it even though it will turn 12 years in Jan 2017.


I have a 2006 Sonata and the check engine light will not go off. Dealer said there was a hole in the gas tank. My mechanic replaced it and there was never a hole in the first one. The check engine light remained on. The code is 0422. My mechanic did a smoke test and saw smoke coming from around the area where the gas tank connects to the gas filter. He replaced the entire gas filter and cannister and the check engine light is still on $1000 plus later! I will never buy another Hyundai. I have driven Toyota s for years and have never had any problems out of one.

1 out of 1 people think this is helpful.

wow as I can see from carfax, the previous owner took it 6 times to the dealer and the could not fix that, then she sold it after 4 months.. to VW I guess the located the problem, the light is off for now.. Unless the just deleted the error codes.. But I had a nightmare with tires, the put some loud tires. So the next set I got the car was wandering, I read also a sonata problem.. Now lucky with american tires :) I was able to return those and take some more advanced tires that fixed that problem..

I have a 15 Hyundai Sonata and I do alot of driving between Utah and Wa st. When I hit 60,000 the car said it needed a service with a countdown on the dash. Then within two days the check engine light came on. I was turning on and off but is now solid. My car get 2mpg worse now and is extremely slow to accelerate now. Normally at idle my car was at 500 rpm now it's its around 1100 or 1200. The code I pulled was a PO1000 I believe. Many thanks

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