general problems of the 2011 Hyundai Sonata - part 1

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at 60 mph, the vehicle lost automotive power. There was no warning light illuminated. The vehicle failed to restart and had to be towed. The vehicle was towed to the dealer, but was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 190,000.

On March 18, 2026 I brought my vehicle to autonation Hyundai for an oil change and full diagnostic. Your dealership’s own diagnostic report showed no knock sensor code, no engine issues, and no active warning lights. My car was fully drivable when I dropped it off. Within 30 minutes of picking my vehicle up, the check engine light began blinking and the car became completely undrivable. It has not moved since March 20, 2026 at the dealership. The dealership did an additional diagnostic and found a knock sensor that was not there during the first diagnostics and have stated that my engine has too many miles to be covered uder warranty.

My 2011 Hyundai Sonata experienced a flashing check engine light and entered limp mode (vehicle cannot accelerate), displaying diagnostic code p1326. This code is associated with Hyundai’s knock sensor detection system (ksds), which was installed as part of a recall-related campaign to detect engine bearing failure in theta ii engines. The vehicle previously had its engine replaced under recall due to known defects involving connecting rod bearing failure. The current condition renders the vehicle unsafe to operate, as it is limited in power and may stall or fail unexpectedly. The system is designed to detect potential engine failure, which is a known safety issue. Despite this, the dealership has not completed proper diagnostic procedures related to the ksds system and potential engine failure. The vehicle has been out of service for approximately one month without resolution. This appears to involve a failure of a recall-related safety system (ksds) and/or a recurring engine defect that Hyundai has previously acknowledged. My biggest concern is that they are diagnosing this issue as an electrical defect rather than the engine itself (which the system is design to warn about) in order to avoid having the repairs covered under the warranty that originated due to the class action lawsuit, and this component was only created and provided to consumers with no charge in order to protect the company from having to continue replacing defective engines.

The vehicle suddenly stopped and died while driving. The mechanic confirms that the engine is gone, contact Hyundai. Ourisman of rockville and Hyundai motor America (hma) refuses to replace the engine for free. The vehicle has now developed a severe engine knock consistent with the well-documented defect affecting Hyundai’s theta ii engines. Hyundai has publicly acknowledged this issue and issued a major recall covering approximately 470,000 vehicles with the following specifications: • model years: 2011–2012 • engines: 2. 0l and 2. 4l • manufacturing period: December 11, 2009 – April 12, 2012 Hyundai and federal regulators identified the safety concern as manufacturing debris that could restrict oil flow to rod bearings. This defect can lead to engine knocking and eventual engine failure. Critically, Hyundai has acknowledged that engine failure may stall the vehicle while driving, significantly increasing the risk of a crash. Hyundai’s official remedy for this defect required dealerships • inspect engines for bearing noise • replace the engine if necessary • honor Hyundai’s extended engine warranty of 10 years / 120,000 miles for affected vehicles. This issue has also been the subject of significant litigation, including the class action lawsuit case no. [xxx], filed January 23, 2018, against Hyundai motor America (hma), kia motors America, inc. (kma), Hyundai motor company (hmc), and kia motors corporation (kmc). Despite these well-known issues, ourisman of rockville failed to disclose any of the following when selling my daughter's this vehicle: 1. The widespread engine defects associated with the 2011 Hyundai Sonata. 2. The recall and safety concerns related to debris restricting oil flow to rod bearings. 3. The extended Hyundai engine warranty covering affected vehicles up to 120,000 miles. This omission is particularly concerning because this defect presents a serious safety hazard and a clear and present danger. Information redacted pursuant to the freedom of information act (foia), 5 u. S.

My 2011 Hyundai Sonata experienced sudden engine failure and the engine is now locked up. The vehicle became inoperable and had to be taken to a Hyundai dealership. The dealership confirmed the engine is locked and not drivable. Hyundai denied the engine replacement claim stating the vehicle has a04/a08 branding indicating the engine originates from a scrapped or rebuilt vehicle. However, Hyundai refused to provide any documentation supporting this claim. They also refused to verify the engine serial number against the VIN to confirm whether the engine is original to the vehicle. A nmvtis vehicle history report shows the title status as active with no salvage, junk, or rebuilt branding. Despite this, Hyundai continues to deny the claim without documentation. This vehicle contains the Hyundai theta ii engine that has been the subject of recalls and settlement actions related to premature engine failure. The failure pattern in this case matches the known defect where engines seize or lock up unexpectedly.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving approximately 30 mph, the vehicle unexpectedly lost motive power. There was no warning light illuminated. The vehicle became inoperable and could not be restarted, and the vehicle was towed. The vehicle was towed to a dealer, where it was diagnosed with engine failure. The dealer stated that the failure was related to a previous recall associated with the VIN; however, the recall number was not provided. The dealer informed the contact that the engine needed to be replaced. The vehicle was not repaired. The contact was referred to the manufacturer for assistance. The manufacturer was notified of the failure but denied coverage for the repair and alleged that the engine failure was a result of negligence in the maintenance records. The approximate failure mileage was 183,000.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving approximately 65 - 70 mph, there was a grinding sensation coming from the front wheels, and the grinding sensation was felt in the steering wheel. The vehicle was taken to the dealer, who diagnosed that the rod bearings and hubs had failed, causing the grinding sound. The contact was informed that the rod bearings and hubs needed to be replaced. The vehicle was towed to a certified mechanic, and the vehicle was repaired. The contact stated that while driving at various speeds the following day, there was a loud grinding sound coming from the vehicle. The sound also occurred while the vehicle was parked. While attempting to accelerate from 25 - 35 mph, the engine started knocking, and the vehicle clunked and jerked. The vehicle decelerated, and the contact pulled over to the side of the road. The contact became aware that the accelerator pedal was not operating as needed. While on the side of the road, the contact turned off the vehicle and attempted to restart the vehicle; however, the vehicle failed to restart. The vehicle was towed to a certified mechanic, who diagnosed that the engine had failed, and the mechanic recommended the engine replacement. The vehicle was not repaired. The vehicle was towed to a different dealer, capital Hyundai of greensboro (801 e bessemer Ave, greensboro, nc 27405), and the contact was informed of NHTSA campaign number: 15v568000 (engine). The vehicle was not repaired because the manufacturer stated that the maintenance history was not satisfactory enough to warrant an engine replacement. The failure mileage was approximately 138,000.

I am reporting a safety-related engine failure involving my 2011 Hyundai Sonata 2. 0t. In November 2025, at approximately 90,000 miles, the vehicle experienced a sudden engine failure while driving, including loss of power and abnormal engine noise. This created an unsafe driving condition and required the vehicle to be removed from service. Component/system involved: the engine (theta ii 2. 0t) suffered a catastrophic internal failure. The engine and internal components remain available for inspection upon request. Safety risk: the sudden loss of engine power reduced my ability to maintain speed and maneuver in traffic, posing a safety risk to myself and other motorists. Confirmation and inspection: the failure was confirmed by an authorized Hyundai dealership, which inspected the vehicle and documented the internal valve train condition through photographs. Hyundai motor America reviewed the claim and issued a written denial. No independent third-party technical inspection was performed. Prior symptoms: before the failure, the vehicle had a history of excessive oil consumption requiring frequent monitoring and oil addition despite regular maintenance. Abnormal engine noise was present for approximately one minute before failure. No warning lights adequately predicted the sudden failure. Additional context: this vehicle is equipped with a theta ii engine, which has been the subject of prior recalls and settlements related to internal engine defects. Hyundai denied warranty coverage alleging “exceptional maintenance neglect”; however, inspection photos show a well maintained valve train with no sludge or oil flow obstruction, only light surface varnish consistent with normal engine aging. I am concerned this failure represents a continuation of a known theta ii engine defect (confirmed by Hyundai technician who performed inspection with obd code p1326 followed by engine failure) and poses a serious safety risk due to sudden loss of engine power while driving.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at an undisclosed speed and making a left turn, the vehicle experienced a loss of motive power. The contact was able to restart the vehicle; however, an abnormal knocking sound was heard, and there was smoke coming from under the hood. The contact was able to drive the vehicle to a nearby residence, where it temporarily remained. The contact attempted to drive the vehicle a few miles to qualify for towing, per the vehicle insurance provider. The vehicle was towed to a local dealer, where it was diagnosed with a rod bearing failure. The vehicle was not repaired due to insufficient engine oil maintenance records. The contact related the failure to NHTSA campaign number: 20v746000 (engine). The manufacturer was made aware of the failure. The failure mileage was approximately 137,600.

The vehicle experiences a recurring defect where the brake light turns on suddenly and the engine shuts off while driving. The failure appears related to the braking system (brake switch circuit), electrical system (can-bus/ecu communication), and engine control (shutdown/stall). The system remains installed and is available for inspection upon request. The shutdown poses a serious safety risk, including possible rear-end collision or loss of power in traffic. The problem has occurred multiple times. The dealership inspected the vehicle briefly but failed to diagnose or document the defect and returned the vehicle within hours, stating “it shouldn’t be a problem,” even though the issue continues. Hyundai has refused to provide recall documentation or authorize a re-inspection. The only warnings prior to shutoff are the sudden activation of the brake warning light just before the engine cuts off.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the engine started to overheat, with the check engine and temperature warning lights illuminated. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 184,000.

I bought this car from someone in April of 2024 and the person who I bought it from said everything was perfectly fine, they brought it to the Hyundai dealership and according to the mechanic there the engine was fine…. I have taken care of the engine since I bought the car, kept up with oil changes and everything…. Until a few days ago when the whole thing ceased up on me while driving down the road to my sons school. I wasnt going fast either, the speed limit is 40mph where I was when it happened, but I’m glad I have quick reflexes because otherwise we would have wrecked the car. Everything shut off on me and now its knocking. There is alot of metal shavings in my oil and my mechanic tried to drain it a few times to get the debris out of the oil but it does no good.

Good day, please note that most of my communication with Hyundai has been over the phone. I sent one an email shortly after the event, and after following up on the phone, I received this following string separately. I can forward you more along the way, but Hyundai is in possession of the call recordings. I was hoping they would cover my repairs, my engine had a lifetime warranty, but during this process I learned that there was a recall for this car that I was never aware of as the new owner. I needed a software update to get any repairs covered. Please reach out to me for more info!.

I am the proud owner of a 2011 Hyundai Sonata this is my 3rd Sonata; we love it due to the worry free long last and warranty. Never had any issues through the years until last night ([xxx]). When getting off from work 6:15pm heading home for about 30 mins. I was driving my car approximately 35 mph when I went to turn a corner suddenly, my car started sputtering, knocking sound and failed to accelerate having traffic behind me not to cause an accident I put my hazard flashers on, and I lean over to the right on grass. Puzzled and scared saying to myself “ what the hecks” what’s going on. The car parked on the side was having hard time staying on and shut down. I then went and opened the hood to check to make sure nothing was in my engine causing it, everything looked normal except, the smell of oil has a burnt smell to it which means in technical terms it has thrown a rod and bent valves and smell of burned electric. Finally, we called aaa, they advised their busy and it will be about 2 hrs. So, I sat there to wait for aaa. As I sat in my car waiting, I started researching online. I currently do not have any recalls or ever got any notice. I came across there is an active class action lawsuit going on for the rod bearing going out in these models and years. After some time, I called aaa back to get an eta, they told us they were extremely busy, it would be about another 45 mins. At that time another tow company pulled up and asked if we needed a tow, we didn’t want to wait longer for aaa to get home so decided to have it towed home … totally cost $175. Today I am trying to contact Hyundai to see what we going to do regarding my car and praying it can get fixed on this recall that I had no idea and thanks god, I turned it off my car could start a fire & burned up. I never got notice about recalls for my engine and it’s sad Hyundai does contact owners ahead to let them know about this problem, think about it we are talking about lives. Thank you for taking information redacted pursuant to the freedom of info.

While driving home from work after 7?pm on the 215?nb freeway, the oil warning light suddenly illuminated, and the vehicle immediately lost engine power. Within seconds, the engine shut off completely, leaving me unable to accelerate or safely maneuver. I was forced to coast across lanes with no power, creating a significant risk of collision and nearly resulting in a rear-end accident. After the incident, I performed a crankshaft rotation test, which the engine failed, confirming that the crankshaft would not turn. I also verified that the timing chain remained intact. The vehicle has since been inspected by Hyundai technicians, who confirmed the engine failure under service campaign 953. Hyundai further communicated via email that my vehicle is eligible under the txxi theta engine settlement agreement and expressed a willingness to discuss my recent engine concerns and the details of the settlement.

I am filing this complaint regarding a catastrophic engine failure in my 2011 Hyundai Sonata. According to Hyundai’s own documentation, service campaign 953, issued in 2018, was never performed on this vehicle. This campaign addresses the risk of connecting rod bearing failure caused by residual metal debris in the crankshaft oil passages.

I own a 2011 Hyundai Sonata with a 2. 0 turbocharged engine. The engine failed/presents issues such as loss of power, rattling, oil consumption, and smoking, which resulted in my engine seizing up. This creates a serious safety risk while driving, to now my car no longer operates. I checked NHTSA’s recall database and found no open recalls for my VIN regarding engine replacement, but I believe this engine defect should be investigated for a recall.

I had just started up my vehicle as normal and exited a parking lot when all of a sudden the vehicle switched off and I was able to safely maneuver to the side of the road and it would refuse to start, and there was smoking coming from beside the engine and we were unsure of what it was. I got it towed to a local mechanic and he let me know that it was an engine failure, and that the starter had burned as result of that.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at various speeds, there was an abnormal knocking sound coming from under the hood. No warning lights were illuminated. In addition, the contact stated that while attempting to start the vehicle, the engine hesitated while turning over. The vehicle was towed to a local dealer, where it was diagnosed, and determined that the long block kit and engine needed to be replaced. The contact was advised that due to the mileage and aftermarket engine in the vehicle, the recall repairs were denied. The contact related the failure to Hyundai service campaign: 953. The manufacturer was made aware of the failure. The failure mileage was approximately 216,301.

I would like to file a complaint regarding a serious engine issue with my vehicle. At times, when I put the car in reverse, the engine suddenly accelerates on its own without pressing the gas pedal. This unexpected acceleration creates a dangerous situation and increases the risk of an accident. I request that this matter be investigated for potential safety defects to prevent harm to drivers and passengers.

On [xxx] iwas driving coming back home from [xxx] by exit [xxx]. The engine turn off and didnt turn back on. I had to get a town to take me out of the highway and pay $141. 00 becide that my engine seized. Now I dont have a car and the car didn't gave me any notification that something it was going on with the engine. If I had any light on the car I wil take it to the mechanic, know I loss my source of income because Hyundai problems with engine. And to get another engine it cost $5000. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at 55 mph and depressing the accelerator pedal, the vehicle hesitated and stopped independently. The contact stated the vehicle went into limp mode independently, with a clinking sound coming from the engine. The contact pulled into a parking lot, awaiting tow truck assistance. Neither a dealer nor an independent mechanic was contacted. The vehicle was towed to an independent mechanic, where the vehicle was inspected and the contact that the lifters needed to be replaced. The vehicle was then towed to the dealer, where it was diagnosed that the lifters, rod bearings, and piston rings needed to be replaced. The vehicle was not repaired. The contact related the failure to NHTSA campaign number: 15v568000 (engine); however, the VIN was not included in the recall. The manufacturer was notified of the failure and denied the claim. The failure mileage was 167,000.

My daughter was driving her 2011 Hyundai Sonata on the freeway at 65mph when the engine light came on and car simultaneously slowed to a stop on 8/21/25 creating significant danger to my daughter and other drivers on the road. There were no prior warnings or indications, and car just had an engine check performed in June 2025. Had it towed to Hyundai on 8/22/25 and Hyundai completed an engine check and it failed. Hyundai told us they'd cover it under the extended warranty if only we could provide complete maintenance records. We were unable to satisfy their record request threshold, as we are not the only owners of this 14-year-old vehicle, so they've requested $10,000 to replace the engine instead. The 2011 Hyundai Sonata is part of the theta ii engine family that has been subject to multiple recalls, class-action lawsuits, and federal investigations due to catastrophic engine failures.

This car has been having white smoke since I got it the smoke coming from the exhaust smells like oil burning.

Not sure . The car has been regulaurly maintenced and one day the emgine complagely seized up going down the road .

While driving at highway speed, the engine suddenly lost power and the brakes locked. I narrowly avoided a collision. This sudden failure left me unable to safely control the vehicle, placing myself and other motorists in immediate danger. This is not only a mechanical defect but a serious safety hazard that matches the exact conditions described in Hyundai’s prior theta ii engine recalls.

While driving on the highway, the motor all of a sudden lost all power and the brakes locked causing a collision. I've never had any problems until then. My car was in tip top shape with no issues until the engine / motor decided to defect. Hyundai she recall this engine issue before someone gets killed.

My Hyundai Sonata has encounter two failing cylinders (compression loss) due to scoring. When driving in the highway I got engine shudder and loss of power (speed) that could have put me in dangerous driving condition, accident or other. These gdi engines are notorious for poor oil circulation due to faulty designed piston rings. Hyundai has long history with these poorly manufactured engines and class action lawsuits. I notified Hyundai but they are not willing to remedy the situation. I have worked with local dealership miller Hyundai, as well as corporate. All I get are excuses and that I’m not covered. These engines are completely problematic with oil consumption and oil blow by, causing seizing, rod bearing failure, carbon buildup, cylinder damage, etc. The info on the internet over customers and these gdi engines is overwhelming. Oil related fires are another issue as well. Hyundai needs more accountability than the class action for rod baring failures. Because of the damage to my pistons, I could have gotten in accident with loss of power on highway…full due to poor piston rings, damage from improper oil flow and near complete engine failure.

I recently got a radiator replaced and now my car won't reverse.

The contact owns a 2011 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The contact was able to pull over to the shoulder of the roadway, where the vehicle failed to restart. The vehicle was towed to an independent mechanic, who diagnosed a failure with the engine. The contact was informed that the engine needed to be replaced. After investigating the failure, the contact related the failure to NHTSA campaign number: 21v727000 (engine); however, the VIN was not included. The manufacturer was not notified of the failure. The failure mileage was unknown.

I purchased this 2011 Hyundai Sonata (VIN: [xxx]) on [xxx]. A few weeks later, the engine started knocking, wouldn’t shift beyond 2nd gear, and wouldn’t go over 60 mph. A diagnostic test at express oil returned the error code p1326, which is tied to Hyundai’s recall campaign 132 for engine failure due to bearing wear. I brought the car to serra Hyundai in trussville, al. I provided my bill of sale, diagnostic code, and a recent oil change receipt, but Hyundai denied my engine replacement, saying there was a gap in service history between 2021 and 2025 — even though I was not the owner during that time. They confirmed it was a recall-eligible engine and admitted the failure matches the recall symptoms, yet are refusing to fix it — while also suggesting I “trade the car in” instead. This is a known safety defect, and I believe Hyundai is wrongfully denying legitimate recall repairs based on ownership history rather than actual engine failure. I am now without a working vehicle. I respectfully request that NHTSA investigate Hyundai’s denial of engine replacements under campaign 132 for new owners and hold them accountable. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

While driving our 2011 Hyundai Sonata on [xxx], my fiancée and I experienced sudden engine failure on [xxx]. The car suddenly lost power and began vibrating violently, then stalled completely and would not restart. We had to pull over in a dangerous area with no power and limited shoulder space, creating a serious safety hazard. A relative had previously scanned the vehicle and retrieved a p1326 knock sensor code, indicating a potential engine bearing issue. He cleared the code temporarily in an attempt to drive the vehicle again. However, when it failed on the freeway, we were forced to tow the vehicle twice—first to our home and then to anaheim Hyundai for diagnosis. Hyundai later denied warranty assistance, claiming "exceptional maintenance neglect" despite the fact that we provided all available oil change records since our 2017 purchase. We were not the original owners, yet were expected to produce records dating back to 2013. No sludge or varnish evidence was cited in the repair order, and the dealer simply claimed a seized engine. We’ve since been denied under both the extended warranty and goodwill policies, even though our engine displayed the same symptoms covered in the theta ii engine class action settlement. This failure was dangerous, left us without transportation, and has caused serious financial and emotional strain. We are reporting this because it reflects a potential ongoing safety risk for other Hyundai owners. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

2011 Hyundai Sonata had a theta ii engine replaced in September 2024 after engine failure. Hyundai paid for the engine through the extended warranty on the theta engines. Check engine light is still illuminated after new engine and after multiple visits to the dealership, they say the wiring harness is bad. Contacted Hyundai corporate who said they will not pay for anymore warranty repairs, even though the wiring harness was damaged from the bad engine or during the replacement. From my understanding, it is dangerous to drive a car with a bad wiring harness due to fire risk, loss of power, or loss of safety components.

The vehicle just died out of nowhere. Would not start back up. Has a clicking noise when trying start and then had a burning smell.

The contact owns a 2011 Hyundai Sonata. The contact stated after the vehicle was serviced, while driving 50 mph and depressing the accelerator pedal, the vehicle lost power. The contact pulled over to the side of the road while awaiting towing assistance. The contact stated that while waiting on the tow assistance, the contact became aware there was smoke coming from the engine. The vehicle was towed to the residence. The contact stated that several warning lights were illuminated. Neither a dealer nor an independent mechanic was contacted. The vehicle was not taken to be diagnosed or repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 112,000.