This car is equipped with a smartkey. Recently it has developed a starting problem that is directly related to the outdoor temp. It has been serviced several times by the local Hyundai dealer. They have replaced the shift interlock switch and the brake light switch. It is below zero this morning (2/21/2015) just one day after the brake light switch was replaced, and again the car refuses to start. When the start button is depressed everything lights up on the dash board but the engine will not even turn over, it is completely dead. The engine imobilizer light also comes on after attempting to move the shifter and the brake pedal becomes nearly impossible to depress! the car will be out of warranty soon. This needs to be resolved. The car has refused to start dozens of times with the very same issues. The car has left me stranded (at home to date) numerous times. When it warms up outdoors later in the day and the temp goes up to 25 - 30 degrees the car starts virtually every time and will start without a problem for the rest of the day. I have researched this problem on this website and other websites and push button ignition problems are very common on this car. Hyundai needs to come up with a proper fix for this problem. Numerous people report having the same switches replaced as on my car their problems were not solved either. It appears that Hyundai has never been able to come up with a proper fix for this issue or it is just to costly to implement. They have continually swept it under the rug.

- Colchester, CT, USA

I was driving on the interstate 2/14/15 and started to slow down due to traffic. As I slowed to approximately 25 mph, my car died. I had enough momentum to make it over to the right shoulder. I had my vehicle towed to the local dealership who stated that my starter had gone bad on 2/14/15. I waited to hear back on Monday, 2/16/15 that they had fixed the starter, but instead they called and stated that my engine had seized up and I would need to purchase a new engine for $5600 (including labor). I made regular oil changes (I was not exactly 8,000 miles for every oil change though), I completed all recall requirements, I had my oil pan replaced Dec 2013, I had the car looked over 100% Dec 2013 and it was found to be in great working condition, & my engine actually turned over when it died on 2/14/15, so the starter made sense. I did some research, and it appears there is a class action lawsuit for ~ 30 incidents where the Hyundai engine seized on this year, make, & model. I am very frustrated that I have to pay for an engine that is pretty much what the car is worth now, when an engine should not seize up after only 120,000 miles when taken care of properly. The fact that it stopped while I was still driving is extremely unsafe and could have easily resulted in a wreck. I believe that the engines on this year, make and model should be investigated and should be recalled due to safety reasons.

- Easley, SC, USA

I was driven on the highway in the 2nd to left lane about 70 mph, check engine light was on and all of the sudden I lost complete control of the accelerator pedal. I pushed it all the way down to the floor several times, no pressure, no control and obviously slowed down. I moved over to get to the right shoulder to stop and see what is the issue, luckily the brakes worked, but many cars were dodging me trying not to hit me. I didn't get in an accident, but sure close to being in one and high speeds. Frightening to say the least. I did make it to the dealer and come to find it is an emission part that failed that caused the car not to accelerate. I did get it fixed but was out of warranty, and past the federal emission reimbursement program of 8 years or 80K miles. I had about 80,200-500 miles on the car. Coincidence, don't know, I am still concerned driving the car, it could happen again! I am just glad I didn't get seriously injured or killed. I didn't get reimbursed for the part that cost $1,500. But I am very concerned knowing that this could happen to anyone with emission controls by the computer in your car. I tried to be proactive therefore the post complaint for others. I guess it takes collateral damage of people losing life for car companies and the wonderful federal government to take notice. Beware most new cars have these systems from what I am told.

- Leesburg, VA, USA

The contact owns a 2011 Hyundai Sonata. The contact stated that while making a right turn at 20 mph, the vehicle stalled. The contact was able to restart the vehicle by shifting into park and reinserting the key into the ignition. The vehicle was taken to a dealer. The technician diagnosed that the oil pump needed to be replaced. The vehicle was not repaired. The failure recurred on numerous occasions. The manufacturer was not notified of the failure. The failure mileage was 77,000.

- Toms River, NJ, USA

Purchased a brand new 2011 Hyundai Sonata. While we were driving down the road, we heard a knocking noise coming from the engine. While we were looking for a gas station to pull over, the check oil light came on, all within a matter of minutes. We immediately pulled over and checked the oil only to find that no oil was registering on the dip stick. We found that odd as we had our oil change just a couple months ago. Had the car towed to the dealership and was told that there was sludge in the engine and we needed to replace it. The cost to replace the engine was $6100. Furthermore, the dealership went on and changed their story 5 times as to while the engine failed. They asked us to provide them with oil change receipts, which we did yet they still denied our claim. Our car had the oil changes done properly and within the time scheduled. Our car was still under warranty yet they denied our claim we have filed a lawsuit against the dealership and Hyundai.

- Riverview, FL, USA

I was driving down the highway, the engine started making a knocking noise. No less than 30 seconds later did the car's engine make a large bag noise and I ran over what felt like parts. I coasted a while down the road and finally pulled the car over to the side of the road. Upon opening the hood I discovered oil all over the intake and exhaust manifolds as well as the radiator. I called Hyundai roadside assistance and had the car towed to faulkner Hyundai in harrisburg pa on 1/19/14. They provided a service loaner and said they would get back to me with an update on the car. I waited until Wednesday the 21st before calling them, only to find out that the engine had seized and they had already taken pictures of the damage and sent them to the Hyundai people to seek warranty coverage. They also asked me for maintenance records on the car. I change the oil myself and always put in full synthetic, so they had me submit receipts from the auto parts store proving I bought oil and filters or the Sonata. I am now awaiting resolution from Hyundai. Will update once I have an answer from Hyundai. This is a pretty serious safety concern, the engine let go at 60+mph without warning, when it let go it blew oil all over the engine compartment and I'm sure on the road as well. Lucky I was driving early in the morning and their was very little traffic.

- Shawnee, KS, USA

I was traveling down a highway when my engine started to make a knocking sound. The check engine light came on, and within 10 seconds my car stopped running. I was still moving when this happened. I was fortunate to be able to coast to a close by side road. I am gravely concerned that this could have happened on the interstate at higher speeds, and the potential consequences of such. I had the car towed to a dealer, and they tell me the engine is shot. I contacted Hyundai customer care, and their response was "what do you want me to do about it." After more research, I have found numerous other instances of this engine failure. If this is an ongoing problem, I feel Hyundai should do something before someone gets killed when this happens. Please note I am the second owner of this car. The mileage at just over 85,000 is mainly highway miles, and the car is serviced regularly.

- Etowah , TN, USA

Oil light blinked on and off twice. Car was making a knocking noise. Stopped to check oil; absolutely no oil in the vehicle. No sign of leak; no smoking; no other indication of problem. Put 3 quarts of oil in the car. Knocking sound was worse. Drove car home and haven't driven it since. This is one of many problems I've had with this car. I get regular oil changes. I haven't had the car looked at yet due to cost and out of warranty. I've read other complaints of loss of oil resulting in complete engine failure. There was absolutely no indication that the oil was even low which I attribute to the faulty electrical system since I've had problems with that as well. It's my opinion that this car is unsafe to drive. I've read this year model has over 900 problems while other year models have average of 230 something problems. Obviously, this car should be completely recalled and replaced by Hyundai dealer.

- Vinton, LA, USA

Tell us what happened: Bought vehicle new and regularly had serviced by dealer. Vehicle died without any warning coming off highway and I had to turn flashers on and place in park to restart. Engine started knocking with no warning and no warning lights illuminated. Had towed to dealer and was told engine had no oil and requires an engine change. Where did it go? there has never been any signs of smoke, burning smell or leaks anywhere and no warning lights ever giving indication of a low oil or low oil pressure indication nor any other engine light warning. Now dealer says we have to convince regional manager that this was not neglect on our part to have covered under the 100,000 mile power-train warranty.

- Honolulu , HI, USA

I am a loyal Hyundai customer who has owned 4 of their vehicles. I took my car in to superior Hyundai North to have a couple safety recall items taken care of. I also would hear a wind type sound sometimes (within a week prior to taking it in) when I would start driving from a stopped position. When I called the dealership service dept. They told me they had bad news. My engine had to be replaced. They said there was no oil in it. I asked them how it could be empty as my car has never leaked, never smoked, never smelled like oil burning, had only approx. 48,000 miles on it, and had been serviced. They had to take some of the engine apart and said since they found no sludge in the engine, it was covered under the warranty. Problem I have is they are replacing my engine with a rebuilt one. They said Hyundai won't approve them to put a new engine in it. I have no way of finding out what happened to the rebuilt engine they are putting in my car and they can't tell me how many miles was on it originally. They told me there was one more car like mine there with the exact same problem. They also tried to tell me it wouldn't hurt my trade-in value. That I didn't have to disclose the engine replacement. One, that's not a moral and deceitful problem that I would never do and two, I believe it's the law that I would have to disclose it. I spoke to one of the salesmen about buying the loaner car I'm driving with the trade of my car and the first thing he told me was the problem with my engine would cause the trade-in value to be less. Hmmm...just as I thought!! they need to either put a new engine in my car or give me the top value of my car with a good discount and price on a new one or they will lose a very loyal customer!

- Hamilton, OH, USA

While driving in the fast lane of a 3 lane freeway on a steep upgrade, the car suddenly and without warning lost a huge amount of engine power. The effect was similar to no longer pushing the accelerator pedal. This caused the cars in back of me to slam on their brakes as well as scaring me as I had no idea what happened. This has occurred twice so far. Hyundai America (ha) is well aware of the problem and from what I have discovered after viewing ha forums, this problem is specific to the Sonata's with the 2.0 turbocharged engines including model years 2011 - 2014. Not only is the problem a result of a poorly designed waste gate control rod, it is a huge safety issue. Inexperienced drivers as well as experienced drivers are going to be harmed. Ha is well aware of the problem and has decided not to cover the repair expense after 60,000 miles. Apparently, a functioning turbocharger is not part of the engine! please insure the ha not only fixes this safety hazard but also reimburses owners for previously charged repair expense. My car was repaired around 56,000 miles andat 67,000 miles, the problem is back. Thank you

- Carson City, NV, USA

While driving the car on interstate 95, the car abruptly stalled out doing 60 mpg, the flashers would not work. I shifted it in neutral and it started after two attempts. We proceeded to get off the interstate onto another four lane highway. About a half a mile down the road, it stalled again. After two more attempts to restart the engine, it did restart and everything seemed fine. Three more miles down the road, the car stalled out again and then started smoking. We could not restart the car and the flashers initially would not work again. After ten seconds, the flashers started to work and then we proceeded to push the car across the highway into a 7-11. The engine had seized up. The car had to be towed to the Hyundai dealer. After calling the dealer the next day, I found out that four cars with the same problem were waiting to be repaired. The dealer is now putting a new engine in the car since it is still under warranty. The problem is they are putting a new engine in the car with the same exact problem. They have not fixed the initial problem. I am afraid this same exact incident will happen again and I will not be as lucky. They are putting my life and my families' life in jeopardy. I want them to buy back the car, this should not happen with only 25,000 miles on the car and an up-to-date car service record.

- Brookhaven, PA, USA

In the span 2 months, there were 2 occasions where my car would not start. I thought it was the battery and had someone jump me and it still wouldn't start. However, after trying several times, car would finally start. One other time I pulled into a store and when I came out, my car wouldn't start. After several attempts, it finally started. Then on November 28th, 2014, my boyfriend was driving my car and it just stopped running. I had it towed to an independent mechanic and they stated that the engine had seized. I did not have any warning or indication that anything was wrong. Today I have to have it towed to the Hyundai dealership and they will let me know the exact problem and if it is covered under the warranty.

- Moon Township, PA, USA

Engine seized.

- Akron, OH, USA

As I began driving my 2011 Hyundai Sonata that morning I heard a rattle whenever my RPM would reach between 2-3K. I contacted my local Hyundai dealership and made an appointment. Today 11/20/14I was told that my engine needed to be replaced. My car was previously in the dealership late September 2014for an oil change and also due to a small knock/bang as I accelerated. The technician found the knock to be a support hitting against the firewall. Upon tightening said support the problem went away. The car was reportedly teat driven by the technician numerous times to conclude that the problem was fixed. Oil change was done as usual and my car was given a clean bill of health (only a recommendation of brakes getting low).

- Chicopee, MA, USA

Car started making knocking noises while driving up hill, losing power. Proceeded to drive it home. Checked oil and appeared completely dry. No engine warning lights came on when car had previously been driven. No oil leaks seen. Added oil and then drove to dealership, where they stated engine needed to be replaced. Regularly serviced car with oil changes, 120K miles with almost all freeway commute.

- Carlsbad, CA, USA

The contact owns a 2011 Hyundai Sonata. While driving approximately 45 mph, the vehicle stalled without warning. The vehicle was towed to the independent mechanic, who diagnosed that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 74,000.

- Plano , TX, USA

In May 2014, while driving at about 40 mph, maybe 1200 RPM, my engine suddenly accelerated to 4500-5000 RPM, without a simultaneous rise in speed. A week or two later, the car did the same, under about the same conditions. The dealer could find no faults or codes, and could not duplicate the occurrence; not surprising since it was sporadic. The problem continued, with considerably more frequency; almost daily. Again I took it to the dealer in late July (mccafferty Hyundai, langhorne, pa), and while a technician was driving with me, the engine raced again. They told me that there was a tech bulletin on this problem, and they would repair the car. The problem was in a module and needed recoding. At least that's what I thought they said. That repair seemed to cure the problem, until September, when a single occurrence happened. I though this was maybe a fluke, but the problem happened several more times in the following weeks. Today, 11/4/14, after several days in the dealer's shop, an insurance service tech said he could find no problem. I am now afraid to drive this car. While the car does not accelerate, maybe it's just a matter of time when the racing engine will cause severe acceleration and a subsequent accident.

- Florence, NJ, USA

The contact owns a 2011 Hyundai Sonata. The contact stated that while making a turn, the vehicle stalled without warning. The vehicle was taken to a dealer where it was repaired under NHTSA campaign number: 10V426000 (steering) but the failure recurred. The manufacturer was notified of the failure. The failure mileage was 67,000.

- Spring, TX, USA

My 2011 Hyundai Sonata like many of the other complaints on here has had catastrophic engine failure due to a snapped rod. Like many of you I have kept up with the regular maintenance schedule and have been shut down by Hyundai for repair under the 100,000 mile warranty. This problem is a serious public safety concern as it happens while the car is in motion and my question is what will it take for the NHTSA to take action and fully investigate this issue and bring it to recall? with the amount of complaints listed on the NHTSA website for this exact issue it seems like they are waiting for injury or even worse to occur before this issue is taken seriously.

- Albuquerque, NM, USA