general problems of the 2012 Hyundai Sonata - part 1

The contact owns a 2012 Hyundai Sonata. The contact stated that while driving at 30 mph, the check engine warning light illuminated, the engine started knocking, and smoke emitted from under the hood. The contact decelerated to approximately 15 mph and drove to her nearby residence. Upon inspection, the contact observed green fluid under the hood. The vehicle was towed to an independent mechanic, where it was diagnosed that the engine had failed and the head gasket was blown. The mechanic informed the contact that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 100,000.

Diagnosed 07/20/2026 with catastrophic oil ring failure requiring engine replacement. Engine can stall due to oil degradation/absence of causing uncontrolled vehicle handling and fire. This would put myself and others at risk. It has been diagnosed at dealership. Complaint narrative: the subject vehicle is experiencing its third total engine failure due to an inherent manufacturing and design defect, presenting a severe and repeating highway safety hazard. The original factory engine failed catastrophically in 2015 at 116,440 miles and was replaced under NHTSA recall 15v-568. The second engine failed in 2021 at 244,710 miles and was replaced under NHTSA recall 17v-226. The third engine (the second replacement) has now failed prematurely at 334,935 chassis miles, lasting a mere 90,225 miles. An authorized Hyundai dealership diagnosed a total failure of the oil control rings. This mechanical defect allows engine oil to bypass the pistons directly into the combustion chambers. This causes severe, rapid oil consumption, spark plug fouling, engine stalling, and total loss of motive power at highway speeds without prior dashboard warning illumination. The manufacturer is failing to provide safe, durable remedies for its federally mandated safety recalls (see warranty info magnuson-moss warranty act (15 u. S. C. § 2301 et seq. / breach of implied warranty of merchantability). Instead, they are installing subsequent replacement powerplants that suffer from the exact same structural vulnerabilities and component lifecycle failures. This creates a continuous risk of sudden engine seizure and traffic collisions for consumers.

Around the end of may 2026, my vehicle stalled without warning while traveling at highway speed. The engine light and eps warning light illuminated simultaneously. The engine cranks but will not start. The vehicle was towed to a Hyundai dealership on June 15, 2026 where the engine failure was confirmed. My safety was directly at risk. The vehicle lost power on an active highway with no warning, creating a collision hazard for myself and other drivers. The failure has been confirmed by the dealership. Hyundai motor America acknowledged the engine failure falls under the txxi settlement agreement and offered a buyback or cash settlement. However, Hyundai has had physical possession of my vehicle since June 15, 2026 and has repeatedly failed to provide a written buyback offer despite multiple commitments to do so. Prior warning signs included the engine and eps lights activating at the moment of failure. No prior warning lamps appeared before that day. The vehicle has 2 open safety recalls as of the date of purchase in November 2025.

Knock sensor needs to be replaced upon evaluation of an inspection on March 27, 2026. It failed a mission codes and upon my understanding the knock sensor one circuit range performance pink wonder single sensor is an engine failure as well as I did an odb test myself on may 19 of 2026 for the knox sensor as well and the check engine dominator reading at 2111 the the code indicated that bank one knox and electrical circuit was out of it upper range or had it perform problem for a predetermined period of time and the code is p0326 and the secondary dtc is a combustion vibration sensor a circuit range performance which affects the powertrain. Also, I have switches with the electrical features in the vehicle as far as the abs and the steering wheel controls and glitching for the cigarette adapter and plug-in area as well on top of the rear passenger side window, having issues with going up and down.

See attached document for complaint.

As I was merging onto the interstate I put my foot on the gas pedal to give it a little more gas then usual to get pulled out and all of a sudden all the lights on the dash board illuminated and it slowly lost all power I was able to move it out of the road . . . There was no loud ,knocking or ticking noises prior to this happening there was no type of any kind of warning . . My car is the push start button so after the car died completely I hit the push button and all the lights on the dash came on the radio worked and everything else seemed to be working it was when I went to put my foot on the brake to start it it would do nothing it would not start at all . . I was still able to put it in neutral even after the incident happened . I had it towed t Hyundai of bristol to have it inspected well they did verifi that the engine was locked up but failed to give me any information on the test they ran or how they keep it was locked up and what locked it up so then they have my car over a week and they tell me I need a new engine but then contact me to tell ke that hma refused to replace the engine on warranty and I had the campaign 953 completed the knox sensor thing before my car broke down so then I had to pay for towing once again out of my pocket to go pick the car from their dealership so when I got there to get my car the service was not that great and my car was in a mess very uncalled for the battery to the car was completely dead with that being said we had to use another battery to just get it turned on to even put it in neutral well then fuel started spraying from the fuel line , the engine cover was left off right along with engine mount was taken off and they even took the belt off there were bolts laying all over my hood of my car and I'm pretty sure we lost a few transporting the car back . . Their service they provided was not business/professional behavior and very disrespectful at that . . Returning my car in that condition was very unnecessary.

P1326, rod bearing failure and seizure of motor without warning.

Vehicle engine caught fire in April 2026! tow company sold for parts without my permission! immediately after gaining possession of my car. I didn't have comprehensive insurance, only basic. I had a brain bleed stroke Nov. 2022 and this is causing stress, setbacks. No attorneys want to take the case because there was no injuries! I jumped out in time. Thank god!.

The contact owns a 2012 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, there was an abnormal burning odor coming from the vehicle. While depressing the accelerator pedal, the vehicle hesitated and stalled. The contact stated that the rear driver’s side brake light was inoperative. The failure occurred on several occasions. No warning lights were illuminated. The contact researched and was made aware of an undisclosed recall; however, the VIN was not included in the recall. The vehicle was taken back to the residence. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 168,000.

While I was driving my car wouldn’t go no higher than 60mph and kept dropping speed but I came to a stop and when I stopped the car was smoking. I heard knocking noise and rumbling noise on the passenger side. It wouldn’t start again.

While driving, the vehicle experienced sudden engine malfunction. The car entered limp mode, lost power, and produced a loud knocking noise from the engine. The failure occurred without warning and created a safety risk because the vehicle could not accelerate properly in traffic. This increased the risk of being rear-ended or unable to move out of dangerous situations. The issue appears to involve the engine (possible internal failure). The vehicle is currently at an authorized dealership and is available for inspection upon request. The problem has been confirmed by the dealership during inspection. The vehicle has been under diagnosis for over three weeks. There were no prior major warning signs before the failure. At the time of the incident, the vehicle suddenly lost performance, entered limp mode, and began making abnormal engine noise. This issue is consistent with widely reported engine defects in similar vehicles. Despite this, the manufacturer has denied coverage and attributed the issue to maintenance, even though regular maintenance was performed. This is a serious safety concern due to sudden loss of power while driving.

I purchased a used 2012 Hyundai Sonata. Within about 2 weeks it broke down while I was in the far left lane of the freeway. The car suddenly stopped accelerating and made a very loud knocking noise. Thankfully I was able to put on my hazards and make it to the right shoulder without getting into an accident but as soon as I pulled over it shut off and the panel lights all came on. Evidently there was a recall on an engine rod and the previous owners advised they were not aware of it. Hyundai has declined the repair on the recalled engine several times and their reasons keep changing. First they said I was missing records (admittedly I was missing one record but then provided it to them), then they stated excessive neglect due to the condition of the valve train (I saw pics of the valve train and is in good condition), and now they state because the ksds wasn't installed. From what I understand, being the second owner, if I can prove the upkeep of the vehicle the extended waranty should cover the repair. I even have the letter from the car mechanic stating the vehicle was maintained and in good condition. It seems a lot of good people are getting declined for repairs on these faulty engines. I have many more documents I could provide showing all of the services done and communications with the company. Due to the size limit I included these ones for your review. Thank you so much for any help you can provide.

My 2012 Hyundai Sonata recently had an engine replacement completed under a Hyundai recall. Immediately after the recall repair, the vehicle began shaking while driving, produced a burning smell, and the air conditioning stopped working, none of which occurred prior to the recall repair. These symptoms started immediately after the engine replacement, indicating a possible improper or unsafe installation. I believe the vehicle is unsafe to drive due to the burning smell and shaking. I contacted Hyundai customer service and was told the issue must be resolved with the dealership. However, the dealership has refused timely inspection, has dismissed my safety concerns, and has declined to provide a rental or loaner vehicle, leaving me without safe transportation. This is a post-recall safety issue, and I am concerned about the risk of fire or mechanical failure due to the burning smell and vehicle instability. I am requesting this issue be formally investigated.

My engine seized on the highway on my way home from work. The service department has been horrid. They lied about who the manager is. They lied about the reason behind not wanting to honor the recall. They are rude - threatened to tow my car today after I waited 6 days to hear back from them about the issue with my car and determination. Was extremely rude. Stated that they were not honoring the recall because there was obvious signs of my engine being tampered with or certain parts on my engine, but could not provide a name of the part or a serial or model number so that this could be verified. I need this addressed immediately.

My 2012 Hyundai Sonata cut off and stopped working! the vehicle locked up in the middle of a main street and would not start back up causing a very unsafe situation. There were no check engine lights on or anything at the time of the incident I immediately had the vehicle towed and inspected it has been determined that the engine is failing! upon research I found out that these engines have had recalls in the past. Carfax shows that the vehicle has been taken in for routine maintenance and oil changes when needed. I am looking to see if the engine replacement could be covered for this vehicle.

The contact owned a 2012 Hyundai Sonata. The contact stated that while driving to her residence at unknown speeds, the vehicle suddenly caught fire while making a u-turn. The brakes and emergency brake were inoperable. The seatbelt was inoperable. The driver jumped out of the window. A pedestrian attempted to alert her of the fire. The vehicle exploded after exiting the vehicle. The contact sustained an injury to her leg, but no medical attention was provided. The fire department extinguished the fire. A police report was filed. There was no report of a crash or airbag deployment. The vehicle was towed to a tow lot. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The manufacturer was contacted, but no assistance was provided. The failure mileage was approximately 136,000. The vehicle was auctioned off by the towing company.

Driving came to a stop ,light turned green made a u-turn to go to the gas station heard a pop noise smoke came from inside the car tried stopping it but the brake pedal sunk into the ground pressed my emergency brake it was seized wouldn’t go down (never had that issue my brakes always work ) I smelled brake fluid and seen the abs light on the dash then the power started to go out and my girlfriend almost got trapped in the car.

I am reporting a pattern of systemic failures on a 2012 Hyundai Sonata hybrid with approximately 131,000 miles. This is my second NHTSA complaint regarding this vehicle and manufacturer. Primary safety concern — engine wiring harness: during a recent engine replacement at an authorized Hyundai dealership, technicians identified damage to the engine wiring harness and documented in writing that the owner “might have issues with drive ability. ” the dealership declined to repair it under the same goodwill program used to replace the engine and returned the vehicle with this known defect unresolved. The harness directly controls engine operation, hybrid system communication, and overall vehicle control. On a hybrid vehicle, a compromised harness presents a serious and ongoing safety risk. This component is available for inspection upon request. Engine failure: the hybrid system warning light appeared prior to failure. The vehicle was towed to an authorized dealership where diagnostic code p1326 confirmed engine failure. The manufacturer acknowledged this and replaced the engine under goodwill. Additional system failures: a pre-scan diagnostic revealed simultaneous fault codes across six systems — engine, transmission, abs, active hydraulic booster, battery management, and motor control unit — including codes u0293 and u1004 indicating lost communication with the hybrid powertrain control module across multiple systems simultaneously. Independent safety advisory: a separate independent repair facility documented in writing that the vehicle presented a severe wheel hub bearing noise and formally advised of an extremely dangerous driving condition. Prior NHTSA complaint: my first complaint to NHTSA involved this same vehicle when the manufacturer refused to provide a loaner during an extended recall-related repair hold, requiring formal escalation before they complied. The wiring harness defect remains unrepaired. The vehicle is driven daily out of necessity.

Came off the highway to a stop sign went turn and the engine just seized and would not start no matter what I did. Had to have it towed to my house. Safety risk was just off the road so I did not get hit. Police stop and told me to get a tow truck. And no warning signs at all.

My 2012 Hyundai Sonata originally had its engine replaced under Hyundai’s recall (NHTSA recall #17v226000) due to the theta ii gdi engine defect. The replacement engine was installed by the dealership as part of the recall. However, the replacement engine has now failed after only ~50,000 miles, exhibiting the same issues (engine knocking, stalling, and eventual failure). This occurred despite proper maintenance and care. The dealership contacted Hyundai, and I also contacted Hyundai consumer affairs directly. Both refused to replace or assist with the failed replacement engine. It is unacceptable that a recall replacement engine would fail so soon and that Hyundai will not stand behind the part they used to correct a safety defect. The issue remains a serious safety concern, especially since engine failure can lead to fire. I request that NHTSA investigate the durability and safety of replacement engines and Hyundai’s refusal to support affected owners when these replacement engines fail prematurely. I have case number with Hyundai 41436693.

Vehicle loses power while driving making it unsafe to drive, it can cause an accident in certain conditions like when passing another vehicle or crossing a street. There is a recall for this issue.

The contact owned a 2012 Hyundai Sonata. The contact stated that while driving at 75 mph on the highway, while depressing the accelerator pedal, the vehicle failed to accelerate. No warning lights illuminated. The contact veered over to the right side of the road, turned the vehicle off, and she noticed smoke coming from the engine. A bystander behind her noticed the flames coming up from the engine. The contact mentioned she exited the vehicle and called 911. No injuries were sustained. No medical attention was required. A police report was filed. The fire department extinguished the fire. The vehicle was destroyed. The vehicle was towed to atow lot. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 160,000.

The contact owns a 2012 Hyundai Sonata. The contact received notification of NHTSA campaign number: 18v934000 (engine, fuel system, gasoline). The contact stated that while driving 20 mph, the vehicle stalled. There was an abnormal knocking sound coming from the vehicle. While driving at an undisclosed speed, the vehicle stalled after five minutes. The engine and the abs warning lights were illuminated. The vehicle was towed to the residence. The contact called the local dealer and was informed that the maintenance records were needed. The contact was using an independent mechanic for maintenance and did not have the records. The vehicle was not diagnosed or repaired. The manufacturer was contacted and opened a case. The failure mileage was approximately 100,000.

This is the first time I have an engine failure. I drove my car 3 min before merging into the route 1 highway. In approximately 800 feet, my car went haywire, all lights in the dashboard went on, the steering wheel got stiff, and the car speed dropped off, I almost got rear-ended. I made an effort to pull over to the break lane. The car shut off and I could not get it to start. I opened the hood, a light smoke was coming out of the engine. I left it open to make sure it doesn't get worse. After 10 min, a state trooper stopped by to check on my safety, I informed him that I called the insurance to report the incident and request a tow truck. After the tow truck dropped off my car in front of my house, I called a mechanic to check it, he informed me that the engine is seized.

My 2012 Hyundai Sonata (VIN: [xxx] ) experienced complete engine failure at 241,433 miles on August 7, 2025. The failure aligns with known safety defect symptoms described under NHTSA recall campaign 15v568000 and 17v226000, which cite premature bearing wear due to metal debris during engine manufacturing. My vehicle had previously received the knock sensor update under campaign t3g and failed the bct (bearing clearance test), confirming bearing damage. Despite this, Hyundai denied my engine replacement claim, stating the issue was related to a fuel pipe and not a rod bearing issue—this is contrary to their own recall documentation and dealer diagnosis. Hyundai continues to deny engine replacement, in violation of their federal recall obligations under 49 u. S. C. §30120. Their refusal endangers public safety by ignoring engine failures that can lead to stalling and crashes. I request NHTSA intervention to compel Hyundai motor America to comply with federal law and perform the necessary recall repairs on my vehicle. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

With no warning my car left me sit on the side of the road and when started the engine made an awful knocking noise. Hyundai denied to replace the engine despite there being at least 2 engine recalls. When I asked why they said it was due to no maintenance records so I provided them with maintenance records like they requested and then they deny it again and say they aren’t replacing the engine because the problem with my engine had nothing to do with the 2 engine recalls my vehicle is affected by.

Engine seized due to extremely low oil despite more than regular oil changes.

On June 24, 2025, while driving approximately 1. 5 hours away from home, a warning message appeared on my dashboard stating: “hybrid system warning. Stop and do not drive. ” I immediately pulled over and contacted my insurance company, who arranged for the vehicle to be towed to the nearest authorized Hyundai dealership (thomas Hyundai in cumberland). The warning clearly indicated that it was not safe to continue driving. Later, I found out that the issue reported (recall 198) have presented cases ending with fire of the engine. It is critical to mention that in January 2025, I attended the official manufacturer recall for this vehicle, which was supposed to ensure safety and reliability. Despite this, the vehicle failed and left me stranded in an unsafe area. Since then, I have been without my vehicle for over three weeks. I contacted Hyundai customer care and opened a case. I was repeatedly told a case manager would call me within three business days, but I never received any follow-up until I insisted. I was eventually assigned a case manager named snowy, and also remained in contact with the dealership. On several occasions, both snowy and the dealership assured me that the vehicle would be ready by Thursday, July 10 and that it was not until then that I could start to request a reimbursement for my rental expenses. I repeatedly asked for confirmation because I am renting a car at my own expense in order to go to work and manage my life. However, on Thursday, July 10, I called again and was told the vehicle would instead be ready by Tuesday, July 15. Then, on Friday, July 11, I received an email stating that the engine had just arrived, and that the dealership was only now able to begin repairs. After that, and only once the car is finished, Hyundai will “review” the case and determine whether I qualify for reimbursement. This is unacceptable. I have been without a vehicle for over three weeks, forced to rent a car entirely at my own expense.

While driving on the highway with my two minor children, my vehicle suddenly shut off without warning. I lost power in the middle of traffic, which was extremely dangerous — we were nearly rear-ended and had to coast to the shoulder. The check engine light had been on for some time prior to the incident, but there were no other warning messages. After being towed, the car would not start again, even after attempting to jump-start it. A mechanic inspected it and believes the engine is seized. I later discovered that my 2012 Sonata is equipped with the theta ii engine, which is known for sudden failure due to oil starvation or bearing wear. Although there are no current recalls on my VIN, the symptoms are consistent with the known theta ii engine defect. This situation put me and my children at serious risk, and I believe this failure needs to be addressed as a safety issue.

Vehicle experienced sudden loss of motive power while merging onto interstate I accelerated to enter traffic and all dashboard warning lights illuminated at once. Engine shut off immediately with no prior knocking,smoke, or warning. Car coasted to shoulder with complete loss of power steering and power brakes. After incident vehicle will not crank or restart , push -button start activates accessories but engine does not turn over when brake is pressed. Vehicle has campaign 953\knock sensor detection system update completed on October 14 2020. This failure matches NHTSA pe-18-003 and Hyundai TSB 22 -em-003h for theta ii engine connecting rod bearing failure. This is a known safety defect causing sudden engine stall at highway speeds . . Dealer inspection is pending vehicle is currently inoperable. . .

While merging onto the interstate my vehicle suffered sudden loss of motive power. All dash lights illuminated ,engine shut off instantly with no prior knock or warning. Vehicle will not crank or restart. Push button start activates accessories only . This matches TSB 22-em-003h for connecting rod bearing seizure. No crash occured because I was able to coast to shoulder but loss of power steering/brakes at highway speed created a dangerous situation.

Hybrid system malfunction do not drive warning light comes on while driving and stalls out the car.

The contact owns a 2012 Hyundai Sonata. The contact stated while attempting to start the vehicle, the vehicle briefly hesitated before starting. After starting the vehicle, the vehicle returned to normal functionality, but the failure became a regular occurrence. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the engine. The contact was advised to the take the vehicle to the dealer for assistance. The vehicle was not repaired. The manufacturer was notified of the failure but provided no assistance. The failure mileage was 137,000.

On [xxx] at approximately [xxx], my [xxx] daughter was using my car to go to work. When she called us and informed my husband that the car did not start. At that point he asked to video call him so that he can visually see what was going on. She was directed to turn on the car again at and that point, the car started then smoke was noticed from coming out of the hood. My daughter managed to open the hood where flames emerged from the center of the engine. She then ran in the house to get a fire extinguisher and managed to put it out and it reignited. She then made a second attempt with another fire extinguisher where it briefly subsided and then grew larger. At that point the fire dept arrived and successfully extinguished the fire and deemed the car totaled after the fire marshall carefully inspected the car. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The contact owns a 2012 Hyundai Sonata. The contact stated while driving 35 mph, the vehicle was leaking engine oil. There were no warning lights illuminated. The contact towed the vehicle to an independent mechanic who diagnosed the vehicle with engine failure. Due to the oil leak, the vehicle was left with no oil in the engine, causing the engine to seize. The dealer was made aware of the failure; however, the contact was informed the vehicle only had a 60-day warranty. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 105,761.