Original owner of vehicle since 2012. In last two years, transmission replaced twice. No clear answers from manufacturer as 100K mile warranty nears end. This time dealership held vehicle 2 weeks before commencing repair. Speaking to other owners, same problem within 3 years of ownership. When in motion transmission will fail and car will not shift into gear causing breakdown in roadway. The first time, got stranded on highway, able to glide to the shoulder. Second time, noticed system slipping during shifts and took directly back to dealership.

- Passaic, NJ, USA

I am experiencing a second issue with the transmission in my 2011 hybrid sonata. The transmission died once at around 80,000 miles and was rebuilt by Hyundai approximately 2 years ago. At the time it originally failed, my transmission experienced the same symptoms that many other owners complained about before it finally experienced a total failure and was dead on the road. Recently (now at 120K miles) my car has started showing the same symptoms that preceded the original failure. This time, however, my vehicle is out of warranty so I willl have to decide whether to invest in another replacement that will also eventually fail or to just scrap the car and cut my losses. Before total failure the reported symptoms do not generate any codes that the dealer can use to diagnose the problem. This was my and apparently many other owners' have experienced the same, before total failure. I had my car in the dealer for several visits during which they simply kept blaming outdated programming that they then updated, but could never recreate any of the symptoms I had complained and even recorded on video and showed them. They said Hyundai could not approve any service to the transmission unless they had "codes" indicating a problem was present. These failures, especially in the hybrid models for at least the 2011 and 2012 model years seem more than random. I believe there is a manufacturer defect in these hybrid transmissions and that Hyundai probably is well aware that there is a systemic problem. I'm sure they have data that shows this is a real problem, and not something related to driving patterns, conditions, maintenance, geography, climate, etc. Please ask Hyundai for their cooperation by releasing data related to transmission failures on these model and years and ask them to look into an engineering issue and possibly issue a recall and/or additional warranty coverage.

- Potomac Falls, VA, USA

This vehicle Hyundai Sonata hybrid has all the issues that the regular Hyundai sonata recalls have engine was rebuilt due to metal shavings in the oil pan, also this hybrid accelerates at times when it doesnt run on battery (engine kicks in) too many issues with this Hyundai Sonata hybrid!!! in motion on highway/ city streets

- Somerville, NJ, USA

Check charging system and check brake light came on at 76000 miles driveing 65 mph in the highway after 3 hours. Collant did not read hot, battery read dead. Vehichle quickly decellerated and I pulled over. Radiator blew neck off and several components of the cooloing system and hoses were melted there is a strong smell of fludge/fule based residue/combustion in cooling system that blew off neck. Battery so week I could not use the key to open a door or the trunk, or move seats. Coolant had just been topped of and system was flushed within 10,000 miles. Mechanic at Kia dealership diagnosed tgat tge gead gasket/cylinder head leaded into the cooling system causing the neck to blow off the radiator and melting several sensors and components of the cooling system that would not have melted or blown from fumes of low coolant alone. Oil levels and quality was good. I photographed the dash lights at breakdown and the coolant levels did not read hot. Check charging system and check brake lights came on. Check brake lights check engine lights had been a problem before. Dealership for Hyundai (coggins Hyundai in deland) says they think a lack of coolant caused issue, but I know I had coolant in the car - they just want to not be responsible for warranty repair, as I am the first owner and have done proper maintainance. I have seen many other people complain of similar issues from when the car is new (check chargins system less than 3000 miles) and the car blowing up/catching fire, etc. Perhaps the reason mine did not catch fire was all the coolant that was released. One car owner insists that all Hyundai will do this between 70,000 and 100,000 miles. Something big is going on with these cars - mine has had continual problems and it should be replaced at huyndai's cost. This should be studied further! safty hazard! read Hyundai forum and the other complaints!

- Miami Beach, FL, USA

Charging system malfunctioned, sensors melted in valve trane, radiator elbow and fill neck blew off, complete engine failure and battery failure. I have had a problem with the "check brake" light and an alarm going off. However, when I stopped driving and had it towed to the dealership they could find nothing. Prior to this incident, I took a photo of my dash, I had 76,499 miles and the coolant meter did not read hot. I had had the coolant system flushed at 65,000 miles, and I had all oil and fluids checked again after this incident. The breakdown: Three hours into a roadtrip, the A/C began blowing warm, simultaneously - the "the check brake" light and alarm came on, and the "check charging system" light came on. I lost power to accelerate (or brake well) and immediately pulled over and took a photo of my dash warnings (76919 miles). The heat sensor was in the "cool" half, the battery gage showed no power. Battery so low key would not start car. I had the car towed. "tech found that elbow and radiator have holes in them vehicle overheated causing engine to blow." Tiffany richardson said "tech believe vehicle was driven with low coolant level causing vehicle to run hot melting sensors in the valve train and the pipes to fail." The tech is wrong, the coolant system was inspected and flushed at 65,000 miles, and was not due for another inspection. I had had coolant levels checked less than 1000 miles ago, and the heating sensor on dash did not read hot, at the point of breakdown or after a road trip 500 miles ago. Others had the problem at 3000 miles! it's the hpcu. The power for both electric motors is routed through hpcu. The inverters allow the A/C motors to be driven by D/C batteries. This caused the "check charging system" error. $15,000 fix. I owe $4000. 100,000 warranty has denied it & I am original owner. Hpcu recalled B4?.

- Miami Beach, FL, USA

We were driving on I81N in Virginia when it sounded like we were driving over gravel.I thought it could have been a tire. Found tires were ok. Waited to pull out safely. Seconds after we entered I81N, we began to lose power, A/C and a warning light indicating to check hybrid system came on in message board. We pulled off at exit 277N and had enough power to find a safe place to pull over.I discovered that the serpentine belt was shredded. We were towed to a Hyundai dealer where the car sat overnight on 9/6/15 until service opened on 9/8/15. The serpentine belt was replaced as well as the water pump belt which was also damaged. The mechanic informed me the new belt was not running true on the tensioner and a ridge had formed on the outside surface of the tensioner. My opinion is that the part was defective because the belt was not running true.

- Gibsonia, PA, USA

The contact owns a 2011 Hyundai Sonata hybrid. The contact stated that while driving approximately 35 mph, he attempted to brake and all the warning lights illuminated. The contact also stated that the vehicle stalled and could be restarted. The failure recurred on fifty occasions. The vehicle was taken to a dealer where it was diagnosed that the transmission, the electric motor, and the oil pump needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 66,000.

- La Mirada, CA, USA

On October 11, 2013 I was driving vehicle at about 30 mph. The traction, brake, and check engine light started flashing. The engine started to accelerate & decelerate at random and vehicle jerked (intermittently) all mentioned lights then stayed on constantly. Vehicle was driven to dealership. Dealership scan tested & found steering angle sensor code in history, then recalibrated steering angle sensor. Vehicle was also serviced for recall regarding lower control arm (replaced). 2nd incident occurred on 10/22/13. I started car in the morning, and all the lights came on. Vehicle was shut off and then towed to same dealer. Service technician could not "duplicate" code. I was told by service that car was fine/operable. 3rd incident occurred on 10/23/13. I was driving and vehicle brake light, & trac light came on. Car was again jerking/surging and accelerating and decelerating at random. Vehicle scanned by technician and multiple "can" codes and steering angle sensor communication code found in history. Technician called technical assistance and was advised to replace motor driven power steering unit, replaced steering column with power steering unit, all ok after repairs (per dealer). Rental car charge incurred totaling $26.28. 4th incident occurred on 1/2/14. I was driving vehicle and traction control lights, brake light, and ABS brake started flashing. Trac light then stayed on constantly. Car began jerking (again) and accelerated/decelerating. Vehicle taken to different dealership. Service writer test drove car while I was in vehicle, and stated there was something definitely wrong w/vehicle and that it wasn't safe to drive. Rental car obtained. Technician looked at car, called support, and was told to charge hybrid battery. Service writer called back and stated that car was ready to be picked up. I refused to pick car...

- Wind Lake, WI, USA

I was coming off of an on ramp to get onto the highway and due to traffic I had to let off the gas. The vehicle suddenly accelerated by itself, causing me to nearly lose control of the vehicle. Another incident took place at a school crosswalk area. I lightly pressed the brakes and the vehicle accelerated by itself causing my head to whip back and me to press harder on the brake. Nearly hitting kids as they crossed in front of my vehicle.

- Winston-Salem, NC, USA

This began as a intermittent hesitant clunk, both during acceleration/deceleration in transitioning between electric motor / gas engine. It has progressed into an unexpected physical jump while going forward and reverse. The latest development was lurching forward at a crosswalk without consciously stepping firmly on the brake. Emails have been sent to Hyundai without a response addressing the problem. The car has been into the dealership twice, where components unrelated to the symptoms were replaced and a manager saying "that's what they do, and Hyundai considers it normal". normal !"!" the problem is widely known, because it has been published in the media, and no dealership will offer anything but a lowball offer on a trade in, just to turn it around and dump it to auction for parts.

- Prescott, AZ, USA