459 problems related to engine and engine cooling have been reported for the 2015 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2015 Hyundai Sonata based on all problems reported for the 2015 Sonata.
Engine failed on 10/24/2025. Hyundai will not honor class action suit to repair engine at no cost to owner. Hyundai state recalls were not completed on the car prior to engine failure. We agree, recalls were not completed prior to failure. Because we never received notification. Had we received notification we would have acted on the recalls immediately and not put our safety, that of our children or the general public at risk by driving a vehicle with an engine that could fail at any moment. We have contested Hyundai's rejection several times to no avail. We are seeking guidance in resolving this mater.
The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at 40 mph, there was an abnormal sound coming from the engine before the vehicle stalled. The contact was able to pull over to the side of the road. The check engine warning light was illuminated. A dealer was contacted. The vehicle was taken to the dealer, where it was diagnosed and determined that the knock sensor had failed, and the engine needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure and offered to buy back the vehicle. The approximate failure mileage was 155,000.
The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at 40 mph, there was an abnormal sound coming from the engine before the vehicle stalled. The contact pulled over to the side of the road. The check engine warning light was illuminated. A dealer was contacted. The vehicle was taken to the dealer, where it was diagnosed and determined that the knock sensor had failed, and that the engine needed to be replaced. The vehicle was repaired. The manufacturer was notified of the failure and offered a buyback. The approximate failure mileage was 155,000.
My vehicle suffered a sudden engine failure that Hyundai confirmed was caused by a recall defect. Hyundai replaced the engine but is refusing to reimburse several necessary expenses incurred solely because of the recall-related failure. There was no warning lamps or messages prior to failure. Expenses: monthly loan payment while car unusable – $242. 55 (refused) first tow: highway ? old ox – $160. 00 (refused) second tow: old ox ? alexandria Hyundai – $170. 00 third tow: alexandria Hyundai ? exxon – $200. 00 fourth tow: exxon ? fitzgerald Hyundai – $205. 00 alexandria Hyundai inspection – $199. 99 (refused) old ox diagnostic fee – $539. 24 (refused) rental car 10/4–10/8 – $208. 90 rental car 10/29–11/1 – $151. 00 total requested: $2,076. 68 total refused: $1,141. 78 Hyundai claims the initial tow isn’t covered because it wasn’t to a Hyundai dealer, that independent diagnostics “don’t qualify,” that a Hyundai dealer’s inspection fee is not reimbursable because dealers are “separate entities,” and that my loan payment is not covered. These denials contradict Hyundai’s recall guidance and the requirement to reimburse reasonable and necessary costs caused by a recalled defect. This engine failure also placed me in real danger. The engine died suddenly at highway speed, leaving me stranded in an unsafe location with no control over the tow provider. Hyundai corporate then instructed me to bring the car to alexandria Hyundai, creating the clear impression those fees would be reimbursed. I relied on their guidance in good faith, and only after following their instructions did they refuse reimbursement. I feel misled, financially harmed, and exposed to unnecessary risk. Due to Hyundai’s conduct and selective denial of valid recall-related expenses, I am preparing to escalate this matter civilly and pursue punitive damages in addition to reimbursement. I request NHTSA’s assistance, as Hyundai’s actions appear inconsistent with recall obligations. Thanks, [xxx] information redacted pursuant to the freedom of informat.
Engine – connecting rod bearing failure. Theta ii engine. Hyundai confirmed the defect via bearing clearance test (bct) on October 3, 2025. The engine can seize without warning, causing sudden loss of power while driving – a clear safety risk. The problem has been confirmed by an authorized Hyundai dealership (hertrich Hyundai of new castle). The manufacturer issued technical service bulletin 22?em?001h (txxi lifetime warranty) covering this exact defect. Despite confirming the failure, the manufacturer has refused to repair the engine. The vehicle is available for inspection upon request. No crash, fire, or injury occurred. Warning signs included engine noise and illumination of check engine light before failure.
Knock sensor has gone bad.
I was driving (i4 highway) when my car suddenly stalled, causing engine failure and almost putting my life at risk, causing an accident. This car has a factory recall for engine damage. I took it to the dealer, and Hyundai refuses to accept the engine repair because the title is rebuilt. The car has no damage to its original engine and is ready to be replaced. They don’t want to assume responsibility.
Engine seized driving down the interstate doing 65 mph in rush hour traffic could have been rear ended or hit vehicles around me trying to get off the road. Complete loss of power. Power steering was still active brakes were barely working. No warning lights (I had the knock sensor recall performed). Engine simply locked up solid. I was able to safely make it to the disabled vehicle lane and put the car in park. Engine had no sludge buildup and looked excellent once it was disassembled by the dealer. All engine bearings had spun. Engine was completely replaced under the extended warrenty.
1. Description of safety problem: my vehicle experienced a sudden catastrophic engine failure while driving, resulting in a complete loss of power and severe engine knocking. This is a known safety defect related to the theta ii engine (specifically, connecting rod bearing failure, often referred to as the ksds defect) that poses a severe risk of stalling and engine fire. The failure rendered the vehicle inoperable and unsafe. 2. Manufacturer's failure to honor safety recalls & warranty: despite this being a known, documented defect covered by Hyundai's own technical service bulletin (22-em-00h-1-1) and the txxi class action settlement—which provides a "limited lifetime warranty" for this issue—Hyundai motor America has repeatedly and wrongfully denied my warranty claim. Furthermore, I discovered through Hyundai's official campaign portal that my specific VIN had multiple unperformed safety and service campaigns, including critical engine control module (ecm) updates (campaign #953) designed to monitor and prevent this exact type of engine failure. Hyundai's failure to ensure these critical updates were performed constitutes negligence and directly contributed to the safety failure I experienced. 3. Evidence of manufacturer bad faith: I have obtained documented proof that Hyundai has approved and performed zero-cost engine replacements for the identical defect on vehicles with mileage exceeding 180,000 miles. This proves that my denial is arbitrary, discriminatory, and demonstrates a pattern of bad faith in applying their safety-related warranty extensions. 4. Escalating consequences: due to Hyundai's refusal to honor its warranty, the dealership has now threatened a mechanic's lien and is charging $50 per day in storage fees. The manufacturer's failure to address a known safety defect is now causing active financial harm. 5. Requested action: I urge the NHTSA investigate Hyundai motor America's systemic failure to honor the safety warranties and complete.
The engine light started to come on and go off. I had the spark plugs changed and I kept regular maintenance done on oil changes and tune ups. Now my engine is knocking and the vehicle is in limp mo. I took to dealership for extended warranty it was denied due to not properly maintained I turned an additional maintenance records the claim was never reevaluated I took my car home which is only 3 mi away in the engine caught on fire before I could get home $9,000 loss I don't know what to do.
Vehicle lost power leaving me stranded. All lights on dash came on, lost power, and barely able to steer to get off the road. We had to have it towed. The vehicle was towed to our mechanic, who states the motor seized up. Mechanic states there is no repair for this issue. Car has just been paid off. Now we have nothing!.
I started taking my car to the dealer in 2023 for engine problems, including high oil consumption and stalling. The dealer kept telling me to return in 1,000 miles instead of fixing it. The issue was officially documented again in March 2024 (ro #131797) with ‘cause: high oil consumption. ’ despite paying \$356. 46 for repairs, the problem was never resolved and now the engine has failed.
Engine locked up.
Engine malfunction putting my safety at risk. This is a known issue under Hyundai’s active campaign, and the issue was verified by the manufacturer. A PA was required and Hyundai is refusing to repair vehicle due to service records prior to my ownership not being available. This issue was identified on 9/4/2025.
P1326.
The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The contact stated that the vehicle failed to accelerate above 10 mph. The vehicle was driven to the shoulder of the road. In addition, the check engine warning light was illuminated. The vehicle was towed to the dealer, where it was diagnosed with a failed knock sensor. The contact was informed that the engine needed to be cleaned. The vehicle was not repaired. The contact referenced an unknown extended warranty for the knock sensor; however, the contact was informed that the repair was not covered under warranty or recall. The manufacturer was made aware of the failure, and a case was filed. The failure mileage was approximately 103,500.
The engine has failed and I was then I formed that there was a arbitration settlement that Hyundai were replacing engines under this settlement. I was not informed of this and now they are saying it has expired. I would like for them to honor this and repair my engine under the Hyundai theta engine defect lawsuit.
In August 2025, my car went into "limp mode" (go no faster than 40 mph and it was lurching and speed dropping) on the freeway, which was scary and dangerous. Once home, I called a certified mechanic. When this mechanic tried to start the car, it made a terrible clacking noise. He told me it sounded like the main bearings were going out. He discovered that there was a recall on this particular vehicle because the main bearings would fail. The local dealer confirmed that the car was subject to the recall and requested that the car be brought in. Because I am on limited income, I could not afford to have the car towed until November 2025. Once there, the dealership verified that the main bearings went out. A claim was made to the manufacturer. The claim was denied claiming "outside influence. " I provided service records to the manufacturer, but before they had all the maintenance records, they closed my case and will no longer take documents or even speak to me or the dealer. I have been without a car for almost 10 months. I have seen documented cases that trying to start the car could lead to dangerous engine fires.
I had a standard oil change done on my car and it was running fine afterwards. Later that evening, my car started smoking and spontaneously burst into flames from the hood. The fire originated in the hood of the car and melted the entire front of my car as well as the entire inside. It burned a lot of fuel and oil, which leaked onto the ground and continued burning on the ground. My car was overtaken by flames in a matter of a few minutes. It burned so fast that there was nothing I could do to stop it. I was not aware of anything wrong with my engine or fuel lines, or anything like that. However, something was very wrong for the engine area to catch fire like that spontaneously.
I bought this Sonata one month ago. Driving down [xxx] in bonita springs fla the car shut down. No noise all dash lights came on I got to a safe place. Sat in the parking lot of fresh market for at least 30 minutes went to start it and nothing happened. No crank nothing. Aaa came towed it to my house. The filling day I checked the battery it is good. So had it towed to scotty’s automotive. They called me Friday morning and said the motor was locked up. According to carfax the car was at brand ton Hyundai in may of 25. I called after I bought the car carfax said they found the alignment was off. I called to see if they did the alignment they said they did not do it. The wholesale it. My thinking is they did service it according to carfax report and knew there was signs something and wholesale it. I did not buy it from brandon Hyundai I bought it from a guy in leigh acres fla. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).
My car 2015 (Hyundai Sonata)started leaking oil, it only had 50,000 miles. My mechanic said the motor had too much pressure and kept pushing oil out. He advised me to take it to the dealership for a motor recall. The dealership gave it back with a list of things to fix. Replaced the valve cover gasket but still leaked oil. I found out these cars have an oil leak problems that are not being addressed. My car went up in flames 2 weeks later. I have done everything I could to save this car but nothing saved it. My grandkids were in the car and it had traumatized them.
Using 5 quarts of oil in 3 days.
I have contacted the guy that sold me the car he refused to fix the recall which is my motor I need something done , Hyundai won’t honor their recall .
The car was on a major highway, went to pass another car and the engine stopped working. While trying to get the car off the road there was almost an accident involving on coming traffic.
We were informed by our mechanic that the engine needed replacement due to a timing chain issue. The engine warning light was blinking continuously, and the rpm would not rise above 1. 9 even under acceleration. Upon further inspection, the mechanic found that the issue extended beyond the timing chain - the entire engine appeared to be failing. When we changed the engine oil, it became dirty almost immediately, and visible metal shavings were present in the oil, indicating internal damage. These symptoms suggest potential engine failure, which is consistent with known issues in some Hyundai Sonata models. We believe this may be related to broader engine defects and request that this be investigated for potential recall eligibility.
The engine light started to come on and go off and when I got the codes ran, it said something along the line of misfire. I had the spark plugs changed and I kept regular maintenance done on oil changes and tune ups. Now my engine is knocking and the vehicle is in limp mode.
On the day of Friday may 16, 2025. I was returning from work on 35 going south in dallas, TX. The engine seized leaving my vehicle in a neutral state. I was in the furthest left lane(passing lane). Lord willing I had enough motion to safely exit on illinois Ave without injury of myself or others. The starter could no longer turn the flywheel indicating to me that the crank shaft had seized. I inspected the oil; it was low but no warning light ever came on(the dealer recently stated the oil was fine when they performed a multipoint inspection(5/10/25) when I went in for the gov mandated theft software update as my car had recently been attempted to be stolen), no sort of warning light came on, nor did the ksds update do anything just like countless other kia/Hyundai owners who's engine seized on the interstate. I towed the car to clay cooley Hyundai dallas because my research indicated that theta 2 engines had government mandated extended warranty even for subsequent owners however as I didnt drive it often & had only replaced the oil(I change every 3k and was soon to do another) once, because I've only owned car for around 6k miles(purchased 10/30/24 I think)before it seized. Hyundai denied txxi claim, stating engine didn't seize due to connecting rod bearing failure, further stating, it was neglect. They said my valve train look terrible. Well its going appear so as the theta 2 was inherently known for poor oil flow, major oil consumption, rough crankshafts & improper deburring, all of which lead to premature ware of internals&seizing. Also they stated there weren't enough oil changes on the carfax in general, well not all shops report auto service so there isn't going to always be records. Furthermore they were failing even in the range of 25k-60k, indicating they were still failing with records of timely service. To my knowledge they didnt perform what I believe they're mandated to do I. E vid/pic evidence that they cant turn the crank, a bct test, oil level etc.
The contact owned a 2015 Hyundai Sonata. The contact stated that after the daughter reached the destination and parked the vehicle, a popping noise suddenly occurred from the engine compartment. After exiting the vehicle, flames were present coming from under the engine hood. The fire department was called to the scene and extinguished the flames. The vehicle was later towed to an impound lot. During the incident, the vehicle was destroyed. The cause of the failure was not determined. No injuries were reported. The local dealer was notified of the failure. The manufacturer was not contacted. The contact indicated that the engine had been previously replaced as part of a recall repair. The failure mileage was 155,000.
I was driving down the road the engine started making a loud knocking noise and as I pulled over it lost power and shut down it would not crank back up I had to have it towed to my house. There was no warning sign.
As we were driving on the highway at 65 mph, the car completely cut off. Fortunately, we were able to immediately steer it off the road to avoid an accident. We had it towed and the mechanic at the auto repair shop said the engine was completely shot. He advised us to have it towed to a Hyundai dealership because he had seen this same situation with other Hyundais with limited mileage and said there may be a safety recall or a class action lawsuit. My car has 60,000 miles and is well maintained.
The contact owns a 2015 Hyundai Sonata. The contact stated that while operating the vehicle, the check engine warning light illuminated, and the vehicle was shaking and vibrating abnormally. Additionally, the vehicle failed to accelerate above 40 mph. The cause of the failure was not yet determined, and the vehicle was not yet repaired. The manufacturer and local dealer were not yet notified of the failure. The failure mileage was 136,000.
I was driving and when turning into a parking lot, I accelerated and the vehicle stalled. It did not go suddenly when accelerating. A couple days later, I use a code reader and have a code listed as p1326. So I take it for a diagnostic at a local shop and I am told it is the knock sensor detection system (ksds). I was advised to take it to a Hyundai dealer because often these vehicles have manufacture warranty since there’s recalls. There have been some vehicles under this recall Hyundai put out as service campaign 966 or 982. They have had vehicles deal with this sensor issue before. Hence why there is a campaign issued. I review to see if there are any recalls on my vehicle and tare none but there are other models listed for this particular issue for Hyundai vehicles. My vehicle was driving fine and it’s fairly new. Low miles then suddenly this happened without warning. I believe it is a recall issue for this model as well.
The car just stopped while driving.
The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the vehicle lost motive power. There was no warning light illuminated. The vehicle was towed to an independent mechanic where it was diagnosed with engine failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 92,000.
The contact owns a 2015 Hyundai Sonata. The contact stated while driving at approximately 30 mph, the vehicle lost motive power. The contact depressed the accelerator pedal; however, the vehicle failed to respond as needed. The contact stated that the vehicle stalled, and there were several unknown warning lights illuminated. The contact stated that prior to the engine failure, engine oil needed to be added every week. The contact had taken the vehicle to a local dealer, where it was diagnosed and determined that the engine had seized and needed to be replaced. The dealer informed the contact that the vehicle was not eligible for an engine replacement because an engine software update had not been performed. The vehicle was not repaired. The manufacturer was informed of the failure and confirmed that the engine could not be replaced before the software update had not been performed. The failure mileage was approximately 122,000.