2015 Hyundai Sonata

Defect. Hyundai Motor America (Hyundai) is recalling certain 2015-2017 Sonata, 2016-2017 Sonata Hybrid, and Sonata Plug-In Hybrid vehicles. The Smart Junction Box (SJB) software logic may not properly interpret the signals received from the multifunction switch, which could cause the turn signal to activate in the opposite direction of what the driver intended.

Risk. A turn signal that activates in the opposite direction of what was intended by the driver increases the risk of a crash.

Remedy. Dealers will update the SJB software, free of charge. Owner notification letters were mailed November 19, 2021. Owners may contact Hyundai customer service at 1-855-371-9460. Hyundai's number for this recall is 210.

Defect. Hyundai Motor America (Hyundai) is recalling certain 2015-2016 Sonata and Genesis vehicles. In the affected vehicles, the warning light to indicate that the parking brake is applied may intermittently not illuminate in the dash due to corrosion in the switch.

Risk. If the parking brake indicator is not illuminated when the parking brake is applied, the driver may operate the vehicle with the parking brake partially engaged, increasing the risk of a crash.

Remedy. Hyundai will notify owners, and dealers will replace the parking brake switch, free of charge. The recall began on August 4, 2017. Owners may contact Hyundai customer service at 1-855-671-3059. Hyundai's number for this recall is 164.

Defect. Hyundai Motor America (Hyundai) is recalling certain model year 2015-2016 Sonata Hybrid vehicles manufactured December 8, 2014, to August 18, 2015, and Hyundai Sonata vehicles manufactured May 28, 2014, to March 18, 2016, equipped with the panoramic sunroof option. Due to a bonding issue with the sunroof wind deflector, the sunroof panel on the affected vehicles may detach while driving.

Risk. If the sunroof detaches from the vehicle it could become a road hazard, increasing the risk of a crash.

Remedy. Hyundai will notify owners, and dealers will repair the wind deflector anchor plate, free of charge. The recall began December 2016. Owners may contact Hyundai customer service at 1-800-633-5151. Hyundai's number for this recall is 152.

Defect. Hyundai Motor Company (Hyundai) is recalling certain model year 2015-2016 Sonata vehicles manufactured May 29, 2014 to February 11, 2016, 2017 Elantra vehicles manufactured January 12, 2016 to February 22, 2016, and one 2016 Sonata Hybrid vehicle manufactured October 15, 2015. In these vehicles, the driver's frontal air bag may be missing a chemical enhancer required for the second stage air bag deployment, resulting in the second stage not deploying in certain crashes. The primary stage will deploy as intended.

Risk. An air bag that does not inflate increases the risk of injury.

Remedy. Hyundai will notify owners, and dealers will replace the driver's frontal air bag module, free of charge. The recall began on May 5,2016. Owners may contact Hyundai customer service at 1-855-371-9460. Hyundai's number for this recall is 144.

Defect. Hyundai Motor America (Hyundai) is recalling certain model year 2015-2016 Sonata vehicles manufactured May 28, 2014, to August 21, 2015. The affected vehicles are equipped with an Antilock Braking System (ABS) warning light intended to warn the driver if there is an ABS malfunction. In the event of an ABS malfunction, the Brake System warning light will illuminate, but the ABS warning light will not illuminate. Since the vehicles have ABS malfunction lights that do not illuminate, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 135, "Light Vehicle Brake Systems."

Risk. If the driver is alerted there is a brake system malfunction, but not specifically with the ABS system, the driver may operate the vehicle unaware that the vehicle's brakes may lock up during hard braking, increasing the risk of a crash.

Remedy. Hyundai will notify owners, and dealers will update the ABS control unit software, free of charge. The recall is expected began on November 30, 2015. Owners may contact Hyundai customer service at 1-855-671-3059. Hyundai's number for this recall is 134.

Defect. Hyundai Motor America (Hyundai) is recalling certain model year 2015 Sonata vehicles manufactured April 25, 2014, to December 4, 2014. The affected vehicles have a front passenger seat belt whose buckle latch assembly may prevent the front passenger from fastening the seat belt.

Risk. If the front passenger seat belt cannot be latched, an occupant sitting in the front passenger seat has an increased risk of injury in the event of a crash.

Remedy. Hyundai will notify owners, and dealers will repair or replace the front passenger seat belt buckle, free of charge. The recall began on September 15, 2015. Owners may contact Hyundai customer service at 1-855-671-3059. Hyundai's number for this recall is 130.

Defect. Hyundai Motor America (Hyundai) is recalling certain 1.6 liter model year 2015 Sonata vehicles manufactured August 29, 2014, to October 28, 2014. The affected vehicles may have been assembled with an incorrect left axle shaft which may result in the shaft separating from the transaxle differential.

Risk. If the left axle shaft separates from the transaxle, the vehicle may stop moving, increasing the risk of a crash. Additionally, a separated axle shaft may allow the vehicle to roll away as the driver and other occupants exit the vehicle or anytime thereafter. A vehicle rollaway increases the risk of injury to exiting occupants and bystanders.

Remedy. Hyundai will notify owners, dealers will inspect and replace the axle shaft, as necessary, free of charge. Owners may contact Hyundai customer service at 1-800-633-5151. Hyundai's number for this recall is 126.

Defect. Hyundai Motor Company (Hyundai) is recalling certain model year 2015 Sonata vehicles manufactured April 25, 2014, through June 16, 2014. Due to a manufacturing error, one or both of the front brake calipers may fracture.

Risk. If a brake caliper fractures, brake effectiveness would be reduced, lengthening to distance required to stop the vehicle, increasing the risk of a crash.

Remedy. Hyundai contacted the affected owners on June 19, 2014 and instructed them not to drive their vehicles. Hyundai dealers will replace the affected brake calipers, free of charge. The recall began on September 12, 2014. Owners may contact Hyundai customer service at 1-800-633-5151. Hyundai's number for this recall is 120.

Defect. Hyundai Motor Company (Hyundai) is recalling certain model year 2015 Sonata vehicles manufactured May 2, 2014, through May 23, 2014. A poor connection within the vehicle's wiring harness may result in a reduction of steering assist from the vehicle's motor driven power steering system or the inability to move the vehicle's shifter from the Park position.

Risk. The reduction of power steering assist can increase the steering effort needed, increasing the risk of a crash.

Remedy. Hyundai notified dealers to suspend sales of affected Sonata vehicles and has published recall bulletin 14-01-024 providing a service procedure to repair the affected vehicles. On June 7, 2014 Hyundai began to contact the affected retail customers. Owners may contact Hyundai customer service at 1-800-633-5151. Hyundai's number for this recall is 119.

The National Highway Traffic Safety Administration (NHTSA) received a letter dated July 13, 2022, petitioning the Agency to initiate a safety defect investigation into loss of motive power allegations attributed to oil drain pan assembly failures on certain Hyundai Motor America, Inc. and Kia America, Inc. vehicles spanning Model Years (MY) 2005-2021. The Petitioners cited examples of complaints indicating that the subject vehicles were experiencing rapid loss of engine oil due to oil drain plug back outs, resulting in loss of motive power and/or catastrophic engine damage. Additional …

On March 29, 2019, the Office of Defects Investigation (ODI) opened two Preliminary Evaluations (PE19-003 on Hyundai and PE19-004 on Kia) to broadly investigate incidents of non-crash fires (regardless of origin or operational status of the vehicle) on various model year Hyundai and Kia vehicles. During the PE investigations, Hyundai and Kia issued several recalls to address vehicle fires, including those due to engine failures involving various engine types. The remedies for the engine failure recalls typically involve engine inspection (to detect existing damage), and if necessary, engine …

The Office of Defects Investigation (ODI) of the National Highway Traffic Safety Administration (NHTSA) received a petition letter dated October 10, 2021, requesting an investigation of possible defects in the electronic throttle control (ETC) system on certain Kia vehicles resulting in the opening of DP21-003. Accordingly, Model Year (MY) 2005-2016 Kia Optima/K5, MY 2006-2015 Kia Sorento, MY 2007-2016 Hyundai Elantra, MY 2007-2016 Hyundai Santa Fe, MY 2006-2015 Hyundai Sonatas are all part of the subject population. The petition was originally filed as a Vehicle Owner Questionnaire that can …

The Office of Defects Investigation (ODI) opened this investigation to determine if the failure of airbags to deploy during severe crashes, in certain vehicles, was the result of a safety related defect. During the investigation a complex failure was studied that can result in non-deployment of subject vehicle air bags and other restraint system devices in severe crash events. The subject vehicles may be equipped with an airbag control unit (ACU) for the supplemental restraint system (SRS) Electronic Control Unit (ECU) manufactured by ZF-TRW. The ECU receives signals from crash sensors …

Certain vehicles may exhibit excessive paint peeling or bubbling of the primer/paint film on the exterior metal body panels: hood, fender(s), roof, door(s), quarter panel(s), and tailgate/trunk. This warranty extension only applies to factory-applied paint and does not cover collision-related paint repairs or vehicles with a salvaged title. Hyundai is …

Certain Santa Fe (TMA), Santa Fe Sport (AN), Sonata (LFA), and Tucson (TL) vehicles equipped with Theta II engines may exhibit elevated engine-out emissions. This bulletin provides instructions for updating the Engine Control Module (ECM) to address this condition.

Certain Santa Fe (TMA), Santa Fe Sport (AN), Sonata (LFA), and Tucson (TL) vehicles equipped with Theta II engines may exhibit elevated engine-out emissions. The California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.

Following completion of Service Campaign 9C2 (Theta II Emissions Improvement), certain vehicles may exhibit a brief hesitation or rough shifting condition during cold start operation. If present, this condition is expected to occur only within approximately the first 1-3 minutes after engine start, while the catalyst is reaching its normal operating …

Some vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin outlines the combustion chamber cleaning procedure for vehicles diagnosed with this condition. All internal combustion engines consume some engine oil during normal operation, depending on driving conditions and mileage, and this …

Certain vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin provides the inspection and repair procedures for vehicles exhibiting this condition. All internal combustion engines consume engine oil as part of normal engine operation. Oil consumption rates may vary based on mileage, …

Following completion of Service Campaign 9C2 (Theta II Emissions Improvement), certain vehicles may exhibit a brief hesitation or rough shifting condition during cold start operation. If present, this condition is expected to occur only within approximately the first 1-3 minutes after engine start, while the catalyst is reaching its normal operating …

Certain 2019 – 2020 model year Santa Fe, 2017 – 2018 model year Santa Fe Sport, 2015 – 2019 model year Sonata, and 2018 – 2021 model year Tucson vehicles may exhibit elevated engine-out emissions. Hyundai is conducting a service campaign to update the Engine Control Module (ECM) Software for vehicles equipped with the (2.4 GDI) Theta II engine to improve …

Hyundai Motor America is currently investigating an ongoing issue with software GDS event #1383 related to 2015MY Sonata (LFA) 2.4L vehicles. The matter is currently being investigated for a resolution as soon as possible. The impacted vehicles related to this event will not show open on the VIN in WebDCS while this event is under suspension.

On Wednesday, October 21, 2026, our 2015 Hyundai Sonata with the 2.4L Theta II GDI engine suffered a sudden, complete engine seizure while traveling about 75 mph on I-25 Southbound near Castle Rock, CO. A family member was driving. Warning lights across the car began flashing, the engine made a loud grinding noise, and the brakes stopped working. Over a long distance, the driver was able to get the car onto the shoulder and bring it to a stop, then engage the parking brake. There was no collision and no injuries, only because traffic was light. The car was towed to a repair shop, then transferred to a second shop, which determined the engine had seized and requires full replacement. This vehicle is covered by Hyundai's Theta II GDI engine campaigns for connecting rod bearing failure. On October 26, 2026, Hyundai told us the Knock Sensor Detection System software update (Campaign 953) was never completed on this vehicle and declined coverage. Neither we nor the prior owners, who are family members, recall receiving any notice of this campaign. All previous check engine lights were diagnosed and repaired at independent shops, including an intake manifold replacement in April 2024, and no shop ever identified an open engine campaign. A full engine seizure at highway speed, combined with the loss of braking, creates a serious crash risk for the driver and surrounding traffic.

A franchise dealership performed a federally mandated safety recall service (ECM Software Update) and a knock sensor replacement on this 2015 Hyundai Sonata 2.0L Turbo. To perform these specific repairs, the technician had to work directly around the intake and turbocharger assembly workspace. Immediately after picking up the vehicle, it suffered a sudden and dangerous loss of power and refused to accelerate normally on the highway, creating a severe traffic hazard. Upon an immediate emergency inspection by the same service center 5 days later, the dealership documented in writing that the turbocharger intercooler hose clamps were completely off/unfastened. Because the technician left the clamps disconnected, the turbo lost sealed pressure, failed completely, and began dumping high-pressure engine oil backward through the air filter intake box. The service center is now refusing to take responsibility for the mechanical safety failure directly caused by their technician's recall repair negligence.

Hyundai Motor America is explicitly refusing to honor the mandatory safety recall and lifetime warranty extension for a catastrophic rod bearing failure on my 2015 Hyundai Sonata (VIN [XXX]). The engine suffered a sudden internal connecting rod bearing seizure while operating, causing a complete loss of motive power and creating an immediate hazard. Hyundai Corporate Escalations issued a blanket denial solely because the vehicle carries a rebuilt title. However, the vehicle's official Hyundai portal confirms that Service Campaign 953 (the Knock Sensor Detection System software update) was successfully completed on XXX. The engine failure matches the exact factory manufacturing defect (internal oil starvation from manufacturing debris) that is the subject of the In re: Hyundai and Kia Engine Litigation. The external collision history that led to a structural/rebuilt brand has absolutely zero mechanical correlation to a sealed, internal crankshaft block defect. Hyundai is acting in bad faith by using an unrelated title status to evade a federal safety recall mandate and escape liability for a dangerous, stalling powertrain defect. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at 20 MPH, the driver-side windshield wiper failed to function properly. The vehicle was taken to an independent mechanic, who determined that the wiper blade was not making proper contact with the windshield due to a bent driver-side windshield wiper arm. The dealer was contacted and confirmed that no recall coverage applied to the failure. The contact associated the failure with NHTSA Campaign Number: 23V180000 (Visibility/Wiper). The contact notified the Hyundai manufacturer of the issue by phone. The failure mileage was approximately 26,400.

I received a notice from Hyundai that there was a Service Campaign 9C2 for my car. My car was running fine but I took it to Jones Hyundai in Belair MD for oil change and the Service Campaign. After this work was done my car lost driveability, poor throttle response and transmission searching for correct gear. I notified Hyundai about my concerns and they replied they opened a case number. Corporate advice so far has been to let the car warm before driving, which has been marginaly helpful. It is hard to merge with high speed traffic because of poor throttle response and transmission searching for correct gear, I have had some close calls. I think cold weather will increase this problem.

I am filing this complaint regarding transmission and drivability problems with my 2015 Hyundai Sonata 2.4L following Hyundai Campaign 9C-2. My vehicle was running and driving perfectly before this update. I have always maintained it on time, followed proper maintenance schedules, and have records documenting its maintenance history. I never experienced these transmission issues before the update. The problems began immediately after the campaign was performed. In fact, I noticed the abnormal shifting before I even left the dealership after picking up my vehicle. Since the update, the vehicle has experienced poor and abnormal shifting behavior. I contacted the dealership to report the problem and also filed a complaint directly with Hyundai Corporate. I was told that Hyundai is aware of the issue, yet my complaint remains unresolved. I also located a document online indicating that Hyundai is aware of this problem. Additionally, I have seen numerous reports from other Hyundai owners describing similar transmission problems after receiving this same update. My vehicle has approximately 82,000 miles. The engine was replaced approximately one year before this complaint. Given the vehicle's excellent operation before the update, my documented maintenance history, and the immediate onset of the problems at the dealership, I am seriously concerned that Campaign 9C-2 caused or contributed to these transmission issues. I am requesting that NHTSA investigate whether this software upda

Ever since the 9C2 software update was completed on 94/26, the car is experiencing hesitations not only in the first few minutes of driving but after the engine is hot. It was driving perfectly before this update.

On May 28, 2026, the panoramic sunroof on my 2015 Hyundai Sonata became off track while I was driving. I could not get the sunroof back into its proper position because it was off track. I continued driving, and while I was traveling on the highway, the sunroof panel detached from the vehicle and flew down the highway. This created a serious safety hazard to me and other motorists. I was not the original owner and did not know the vehicle was subject to a recall. After the incident, I researched the vehicle and discovered Hyundai's Sonata Panoramic Sunroof Recall, Campaign 152. Hyundai's official website states that my vehicle is affected by the recall. Hyundai's recall description states that the wind deflector can interfere with the movable sunroof panel and, in some cases, cause the panel to detach from its mounting tabs. It specifically warns that if the panel detaches while the vehicle is in motion, it could become an obstacle to other drivers and increase the risk of a crash. This is what happened to me. After discovering the recall, I took the vehicle to a Hyundai dealership to have the recall addressed, but the dealership refused to perform the recall repair. Hyundai's website states that the dealer will repair the wind deflector anchor plate at no charge. I'm asking NHTSA to determine the appropriate remedy when the recalled condition actually occured and resulted in the sunroof panel detaching while the vehicle was in motion.

Am seeking assistance regarding a sudden and unexpected engine failure with my vehicle. The Sonata only had approximately 80,000 miles on it when the engine failed. Prior to this happening, I had never experienced any problems with the vehicle. There were no warning lights or other indications that there was an issue with the engine, and the vehicle had passed inspection. The engine failure happened completely out of the blue. I have also kept up with the vehicle’s maintenance, including regular oil changes. I recently replaced the battery and tires as well. Hyundai previously denied my claim, stating that the vehicle’s salvage title was the reason for the denial. However, I would like the circumstances of the engine failure and my maintenance history to be fully considered. The vehicle had relatively low mileage, was maintained, passed inspection, and showed no warning signs before the engine suddenly failed. I can provide maintenance records, receipts, inspection records, photographs, repair records, and any other documentation needed to support my claim.

"I am filing a complaint regarding severe vehicle jerking, engine surging, and rough transmission shifting immediately following the completion of Hyundai Service Campaign 9C2 (TSB 26-01-013H-1) on my 2015 Hyundai Sonata. The vehicle exhibits dangerous hesitation and lurching during cold starts. This behavior creates a traffic hazard when pulling out of driveways or into intersections during the first 3 minutes of operation. The manufacturer has acknowledged this cold-start defect in an internal 'Drivability Information' memo but has not provided a permanent remedy to repair the software logic."

After receiving the Hyundai Service Campaign 9C2 update on my 2015 Hyundai Sonata on XXX, I have started having jerky acceleration when the car is first started and am driving. Also, while driving at highway speed (~65 mph)) and I take my foot off the accelerator to coast, the engine RPM drops suddenly, anywhere from 250 rpm to 750 rpm, then recovers abruptly to where it was at prior to the drop (typically around 2000 rpm). The engine rpm also drops while driving at slower speeds and recovers but is not as noticeable as it is at highway speeds. It was not doing this prior to the Service Campaign. There are no check engine lights or pending codes. I brought it back to the Hyundai dealer and discussed the issue with them on XXX. They acknowledged it was likely due to the Service Campaign and they did not want to keep the car to look at it and said no damage was being done and it was safe to drive. They said a fix was in the works but did not know how long until it was released and I should receive information in the mail on it. Video link [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

In March 2026 Hyundai did an emissions update Campaign 9C2. Since that update my 2015 Hyundai Sonata SE has run rough and shifted hard. Hyundai stopped doing the update in May 2026. Hyundai has not provided any update to fix the problem they created. I am worried the update is damaging the motor and transmission of a car that was running just fine prior to the update.

The engine failed due to the known recall defect, dealer confirmed loss of compression in cylinders 2 & 4. I am a federal employee stationed overseas on official duty orders, and Hyundai Motor America is delaying safety recall remedies and buyback negotiations since June 9th.

Engine locked up, crank bearing failure, found out there is known failures with this problem and Hyundai had a class action suit against them in the past and issued lifetime warranty for this engine due to this problem. Took car to local dealer, Clay Cooley in Sherman TX, they have been great but Hyundai corporate has denied the claim stating lack of maintenance records. Car has 175,000 miles on it, I have only owned it for about 5-6,000 miles. I have changed the oil in it twice myself I was able to prove one of those with a receipt but I don't have the other receipt and have been unable to get it. The dealer has records of oil changes up to 150k miles then I was able to find additional proof of other oil changes through car fax at smaller lube shops. The previous owner before me changed their own oil also and did not keep receipts I reached out to them with no luck. Ultimately there is only about a 10k mile gap of unprovable maintenance, this engine model has a known issue, it did not make it to 175k miles without proper maintenance, I can't control what previous owners did with their receipts but lifetime warranty should be lifetime not only if you can prove every detail from people you can't control.

I bought this car new in 2015, when I was at 97000 miles they had to replace the motor and turbo, I am now at 155844 and they are telling me that basically all 4 cylinders have low compression, cylinder 3 is the worst. They are telling me that this car has to have a new motor. I have not done anything to this vehicle to cause no compression. They want me to pay around 8800.00 to get this fixed.

Issue- fuel pump/supply line causing fuel to leak and fuel smell around the outside of the car. This can cause a major fire, explosion, death for myself and others around me. Problem has been confirmed by auto repair shop. No warning messages on car dash board, just strong smell of gas. Replaced gas cap and smell is still there.

Brake lights not working properly.

The contact owns a 2015 Hyundai Sonata. The contact stated that while driving on several occasions at various speeds, the vehicle lost power, and the check engine warning light was illuminated. The vehicle was taken to a dealer where it was diagnosed that the engine had failed and needed to be replaced. The vehicle was repaired, but the failure reoccurred within a year. The vehicle was taken back to the same dealer where it was diagnosed and determined that a software update was needed. The vehicle was repaired, but the failure persisted. The vehicle was then taken back to the same dealer, and there was oil on the pistons and a tune-up was needed. The vehicle was repaired, but the failure persisted. The vehicle was taken back to the dealer, where it was advised that an oil consumption test could not be provided until the pistons had failed. The manufacturer was notified of the failure, and a complaint was filed. The failure mileage was approximately 88,000.

My Hyundai Sonata engine stalled out while driving on the highway. I had it towed to a dealership with the hope they would fix the issue because it was supposed to be covered under warranty from a recall. The dealership said the engine replacement would be covered as long as they got approval from Hyundai. Hyundai apparently only asked that specific dealership for the service records that they had, didn’t even reach out to me or try to find any other service records on the vehicle and denied the claim for “neglect of maintenance” because that dealership only had records from 0-90,000 miles. The dealership got back to me and told me the news and I told them that I will get all service records from 0 miles to current. I got all those records together and sent them to the dealer. A week later they called and said Hyundai was again going to deny my request because of the same “neglect of maintenance” which isn’t true based on the records I have and they have. I have driven the vehicle less than 10,000 miles and there has been nothing wrong with it. No check engine lights ever and regular oil changes.

Vehicle: 2015 Hyundai Sonata VIN: [XXX] Mileage: ~85,000 Description of the Problem: While driving, the vehicle suddenly began producing thick smoke from under the hood without warning. I safely maneuvered to the shoulder to avoid an accident. The engine subsequently seized completely and became inoperable. My mechanic diagnosed this as a known internal manufacturing defect in the Theta II engine (connecting rod bearing failure), a widely documented issue for this model and production year. Oil and coolant levels were confirmed normal with no leaks, ruling out maintenance neglect. I initially paid for an unnecessary starter replacement before this diagnosis was confirmed. This is a serious safety hazard that could cause loss of engine power and control while driving, posing a risk to myself and other drivers on the road. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Since the 9C2 update on June 24, 2026, my vehicle has not driven the same. I'm experiencing clunky or harsh gear changes at low speeds, especially during stop-and-go driving. When I slow down and then accelerate again, the vehicle sputters or hesitates before responding. While driving at lower speeds, I also feel intermittent skips or small surges, almost like bubbles or brief misfires. These symptoms were not present before the 9C2 update, and they have noticeably affected the drivability of the vehicle. It was suggested the transmission needed time to "relearn" driving patterns, but it has been several weeks with no change

1.) Following Hyundai's 9C2 Campaign update for the ECU that was completed back on May 27th, 2026, my 2015 Sonata went into limp mode [solid check engine light present] while I was accelerating up an on-ramp on the 2nd drive cycle since the update was performed. I was already far away from the dealership so I was forced to limp it to my local shop that I regularly use to have it checked out. It was confirmed that the code on the vehicle was P200A for intake manifold runners. Since the update was for smog regulation, the code was cleared in order to see if it would come back. Since then, it has not, however the vehicle continues to have one persistent problem. The RPMs will dramatically dip and then surge back upwards while the car is coasting (no gas and no brake applied). 70% of the time, you can feel the car violently jerk as it appears to try and correct itself. 2.) I've brought this car to multiple dealerships, have a case open with corporate and have also found that this is a systemic issue with this specific update in these cars. All and all, nothing has been done. I'm repeatedly turned away over and over again because their techs are only permitted to look into it once they have hard evidence of a fault. In this case, that would be a dashboard light. I'm told that I may only return if the check engine light comes back, which as I mentioned previously, posed a HUGE safety risk to myself the first time it appeared. If I can only go 55mph down the highway, I am at risk of

Engine / Short block assembly / Connecting rod bearing seizure. The engine suffered a sudden, catastrophic seizure while I was actively driving on a steep incline mountain road with a cliff on one side and forest on other. The vehicle experienced an immediate, total loss of motive power, forcing an emergency maneuver onto the shoulder in 5 seconds with no power steering or power brakes, creating an extreme collision hazard on a high-speed incline. The rod bearing melted due to a manufacture defect and could have also possible caught fire in heavy fire country. The fuel pump was also leaking recently and just replaced. They are nearly $1800 for a new pump because of price gauging because they are in "high demand". The Check Engine Light was solid (not flashing) for a thermostat code (P0128) due to extreme internal friction/heat from the failing bearings. There were no flashing KSDS warnings or physical signs of engine overheating. My car was denied a new engine under a Federally Mandated Warranty explicitly stating the exact symptoms of internal engine defect that happened in my car under "owner neglect" even though I have changed my oil regularly and even before the manufacture recommended time frames to do so. I've changed the valve covers, 02 sensors, thermostats, and plenty more on this car than any other car I have ever owned proving I'm actually an exceptional owner. I remained nice to all corporate staff during this process while they denied my car proper care under a F

Driving vehicle at slow speed crossing an intersection and engine completely shut down. The engine has completely seized and needs replaced due to a known recall. I have only owned the vehicle for 7 months. Hyundai is refusing to pay for engine replacement claiming a previous recall prior to me owning the vehicle should have been completed. I only drove the vehicle 1,000 miles in that time at nothing over 50 mph. There was no notification to me about this recall.

I was driving my 2015 Hyundai Sonata approximately 35 mph after leaving the Hyundai dealership following an engine replacement when the hood unexpectedly flew completely open without warning. The hood struck the windshield, completely obstructing my forward visibility and creating an extremely dangerous situation. I was able to safely pull over without causing a collision, but the vehicle sustained extensive damage and was declared a total loss by my insurance company. During the same service visit in which the engine was replaced, the dealership recommended replacing the hood latches, but I declined that repair. Hyundai later informed me that the hood latching system was functioning properly after the engine replacement and that the vehicle passed its post-repair inspection and road test. Approximately one mile after leaving the dealership following the engine replacement, the hood unexpectedly opened while I was driving. There were no hood-ajar warnings, warning lights, or other indications that the hood was not properly secured before the incident. The sudden loss of visibility created a serious risk of a crash that could have resulted in severe injury or death. I am submitting this complaint because I believe this incident represents a significant vehicle safety issue that should be investigated.

We are the sole owners of the 2015 Hyundai Sonata. Over the years the dashboard has deteriorated and developed cracks along the entire length, including over the area of the passenger airbag. We are currently concerned as to what would happen in the event of an accident that would trigger the air bag causing the dashboard to explode and send splinters all over the place, possibly causing severe damage to the passenger. I took the vehicle to Lehman Hyundai and they could not give me a definitive answer as to whether this was a dangerous situation or not. They gave me an oral estimate of $3,500 just for the part, and who knows what the labor costs would be. Whether I end up donating, gifting or selling the car, I am truly concerned about the safety of this vehicle and the condition it is in.

This vehicle had a recall, 201, for the smart junction box. This was due to the blinkers not working properly. The software update was performed, however, the problem still exists. This was due to the smart junction box. Now, aside from the blinker issue, the ac stays on when the engine is turned off, lights come on by themselves, the media screen goes randomly into night mode, daylight running lights are constantly in night mode, smart junction box failure. I have not taken this to a mechanic as of yet, the dealership is aware, and I opened a case with Hyundai case #42940056, however, I have not received a call from my service advisor or Hyundai. They offered to do diagnostics, but, if these problems are not about the safety recall, I would have to pay $350 for diagnostics, unless I get the problem fixed by them. This car has 66k miles with a new engine installed at 59400 miles! At this point, I have the car parked, battery disconnected, and looking for the most efficient way to fix the problem, which must be performed by specialized equipment.

On June 22, my 2015 Hyundai Sonata suddenly lost all electrical power without warning. The vehicle stalled and would not restart. There were no warning signs beforehand. After the incident, the car had no electrical power and was inoperable. Further inspection determined that the engine had failed and required replacement. I maintained the vehicle with regular oil changes and was unaware of Hyundai’s Service Campaign 953 (KSDS update). I was never notified that this campaign needed to be completed, and I believe that failure to receive notice contributed to Hyundai’s denial of my engine replacement claim. I purchased the vehicle December 19, 2019. I was never notified by the dealer or manufacturer

I had the Service Campaign 9C2 and TSB 25-01-087H recall emissions update performed. I immediately noticed degraded performance with my vehicle. It's very jumpy/stuttery after I first start driving and feels less responsive. Even after driving for a bit, it feels like it drives and shifts oddly. It is not as smooth as it used to be. My car drove fine prior to the update and immediately felt different after the update. It's now been over a week and it's still like this, so it's not the engine computer adapting or something like that.

The contact owns a 2015 Hyundai Sonata. The contact stated that while operating the vehicle, exhaust fumes were noticed inside the cabin, and the check engine light illuminated before the engine stalled. The vehicle was towed to a local dealer. The cause of the failure was not determined. The manufacturer was notified of the failure. The failure mileage was unknown.

The contact owns a 2015 Hyundai Sonata. The contact stated that the vehicle was taken to a local dealer who performed an emission software upgrade. Later, while driving, the air conditioner blew hot air, the thermostat increased to high, and an engine overheating warning message was displayed on the instrument panel. The vehicle was taken back to the dealer, who diagnosed that the thermostat had failed and needed to be replaced. The thermostat was replaced, and the failure was remedied. The manufacturer was notified of the failure. The failure mileage was 74,000.

Engine misfiring and low compression

Oil consumption

VEHICLE: 2015 Hyundai Sonata, 2.4L Theta II GDI engine Mileage at time of incident: [ 93k Date update performed: June 2026 Dealer/location where update was performed: Fitzgerald Hyundai Gaithersburg, MD DESCRIPTION OF PROBLEM: After my vehicle received the ECM software update issued under Hyundai Service Campaign 9C2 (ECU Software Update for Theta II Emissions Improvement, TSB 25-01-087H / 26-01-013H-1), the vehicle began exhibiting noticeable jerking/hesitation during acceleration that was not present before. For this vehicle this happens consistently after a cold start then does not happen again.

The incident began following a routine maintenance visit on March 16, 2026, and has been a continuous, ongoing safety hazard every single day since. While the vehicle was in for routine brake service and an oil change, the dealership automatically applied an open, manufacturer-mandated ECU S/W Update THETA II (26-01-013H-1) under Service Campaign 9C2 Emissions (Code NP001-SC9C2) without my prior knowledge of its drivability side effects. This software flash directly compromised the vehicle's powertrain logic, creating two notable, daily safety failures. First, within the first 5 minutes of engine startup, and most pronounced on every cold engine startup, the throttle delivery is highly erratic, causing uncommanded low-speed surging. In a specific incident in a parking lot following a cold start, I accelerated to approximately 15 MPH and completely removed my foot from the accelerator pedal to coast. Instead of slowing down, the vehicle unexpectedly lunged and pulled ahead forcefully against my intent. Second, even after reaching full operating temperature, the vehicle completely loses safe and predictable engine braking at greater speeds; when lifting off the gas pedal, engine RPMs aggressively drop, causing the vehicle to coast freely as if in neutral. Re-applying the accelerator causes a violent "phantom shifting" downshift and a hard transmission lockup. My safety and the safety of others are put at risk every time the vehicle is driven. The low-speed throttle surging crea

On October 2024,I brought the car in to RickCase Hyundai for maintenance and to address an oil leaking issue. I texted the service advisor, “Please do not do the oil change till you find out where the oil is leaking”, I’m replacing it frequentlyWhen I picked up the car and inquired about the leaking, the he told me that there was not an issue. January 2025, the car was driving rough again, noticed the oil low and filled it up. February 2025 driving on 595, The car stopped. I had it towed to Rick Case, they told me I needed to replace the piston. I said no this has to do with the oil consumption issue that I brought the car in October that you never addressed. The four new spark plugs that were put in were burnt on the tips. They went through the warranty issue to get the engine repaired and it was denied. I said this is not a warranty issue. This was a mistake on your part because you never address the oil consumption issue in October 2024. As of June 12,2026, the dealership still has my car. When I call and ask, What’s going on with my car. The only response I get is we are trying something else it’s going to take some time. Last summer, the service advisor told me he was going to fix my car, wanted me to come pick it up and drive it for 1000 miles and bring it back. They couldn’t fix the car. They never offered a loaner. The vehicle suffered a catastrophic engine failure and completely stalled in the middle of a live road, creating an immediate highway safety hazard. the ve

The contact owns a 2015 Hyundai Sonata. The contact stated that while idling at a stop light the vehicle suddenly stalled. The engine did not restart and the vehicle was pushed to a nearby parking space. During the failure no warning lights or messages had displayed. The cause of the failure was not yet determined. The manufacturer and local dealer were not yet contacted regarding the failure. The failure mileage was 123,000.

2015 Hyundai Sonata 2.4L Theta II GDI engine experienced complete failure due to connecting rod bearing defect. Vehicle was taken to a Hyundai dealership prior to failure to report engine knock symptoms. Dealer confirmed KSDS (Service Campaign 953) was installed but performed no inspection and provided no repair order. Engine subsequently failed with no warning light activation despite KSDS being installed. This is a known defect covered under the Theta II class action settlement lifetime warranty. Warranty repair has not been provided and no loner car has been provided.

The contact owns a 2015 Hyundai Sonata. The contact stated while driving at various speeds, the vehicle skipped and failed to exceed 35 MPH. The contact received notification of Hyundai Service Campaign Number: 9C2 (ECU SOFTWARE UPDATE FOR THETA II EMISSIONS IMPROVEMENT), and the vehicle was towed to the dealer, where it was diagnosed and determined that the catalytic converter was clogged and needed to be replaced at the owner's expense. The vehicle was not yet repaired. The contact's son, who was an independent mechanic, determined that the ECU might have sent erroneous signals to the O2 sensors, who then sent excessive fuel into the catalytic converter, causing a catalytic converter clog. The manufacturer was notified of the failure and was informed of the Service Campaign notification, but the manufacturer denied assistance due to the mileage and lack of warranty coverage. The failure mileage was approximately 140,000.

The contact owns a 2015 Hyundai Sonata. The contact stated that while driving at lower speeds, the steering wheel became difficult to steer in either the left or right direction. The Traction Control, Power Steering, and the high-beam warning lights were illuminated. The vehicle was taken to a local independent service center, where it was diagnosed with error codes: C167286, C126008, C136008, C126002, and C168808. The vehicle was not repaired. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 195,000.

Was driving the vehicle up Berthoud Pass on [XXX] . Was a few miles past Berthoud Falls and realized that the vehicle power diminished, noticed smoke coming from the engine. Pulled over and noticed leaking underneath the engine. It appears that a bolt came loose and punctured the engine block. After further research, it appears that this engine recall should have applied to my vehicle, but did not: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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.

My vehicle has a lifetime warranty that is currently not being honored. It is currently in limp mode and showing a code P1326 which is an engine failure and possible fire hazard. The dealership has had my car for three weeks and have made no attempts to repair my vehicle which they are required to do by law under the Theta II Settlement. I was lied to by both dealerships. One stated my vehicle was branded as junk which was false. And now they are denying me due to mileage which shouldn’t be factor since the warranty is a lifetime warranty.

The contact's son owns a 2015 Hyundai Sonata. The contact stated that while the vehicle was being driven at 40-50 MPH, the vehicle began to jerk. The check engine light was illuminated. The vehicle was taken to an independent mechanic who determined the failure was related to the engine. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 102,198.

Car stopped in the middle of the road , with warning beeps and warning messages on the dashboard saying "Check Charging System" .Engine was still running but even though I did accelerate - car did not move . I put on the emergency lights and turned off the car . Turned on the car few seconds later and was able to drive then but the check engine light was on. Slowly drove back to the home as I was less than a mile from the home. It happened on a local road with speed limit of 35 MPH and thankfully vehicles behind me stopped until I pulled over. Me and and 7 year old kid was in the car at the time of this incident

On 5/27/2026 I was driving home from work. Had just gotten off the frwy , was driving around 35-40mph, all of a sudden , engine turned off, after coming to a stop, holding up traffic, i put in park, and nothing, not crancking, a new battery was imstalled, 3 weeks prior, have recoreds of all maintenance! Checked oil level was good, radiator, had fluid, and fas tank was 1/2 full! Pushed to a side street ,Uberd, back home, later that evening , had car towed approx 5 miles to my house. Checked all fuses, ignition, and starter! Spoke with Local Hundai Dealership, scheduled a maintenance diagnostic to be performed! Could have been an accident, first time, ever experienced, such an issue!

My infotainment unit stoped working after an update that was pushed to the car by Hyundai. My battery was beginning to show signs that it needed replacing (not cranking in the cold temps or needing a few tries to start), so I went to Advance Auto to have the battery replaced. Once back in the car, everything was working fine (radio with sirius XM, back up camera, Navigation, Android and Apple car plan, the clock, everything). When I went to reset the clock, the car showed a software update was availabe and needed to be downloaded. Never before, had I seen this. So, I selected update. After 30 minutes of seeing it say downloading, it then started to say install. It gets to where it says, the radio needs to be restarted to complete the update and then gives error code 604. Now the telematics or infotainment works. I reached out to mapit, Hyundia and Bluelink who all say, "to bad for you, buy a new one for $1600". I did not ask for the update, I did not go looking for the update and I did not push the update to my vehicle, Hyundia did and me and the other 2000 owners who are going through this should not have to pay that kind of money to have it repaired. If they new they were shutting down 3G service, then don't push the update to my car. Hyundia has admitted the issue for Hyundia Tusons and a few other vehicles but not for 2015 model Sonata's. So for Tusons they send out 3 SD cards to fix the issue, but refuse to do so for all the cars they pushed an update to that as they cal

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.

I have the 2015 Hyundai sonata with the 2.5 GDI engine that eventually will seize due to internal damaged caused by manufacture design flaws. My Hyundai threw a P0010 code which causes my car to idle high and causing low vacuum affecting my brakes. I had a diagnostic test done at a Hyundai dealership that told me it was a cvvt cam sprocket issue and that it was the beginning of the end of the engine, They quoted me 3700.00 but the engine was to far gone and this repair would only accelerate the engine to seize. They said since the engine isn't seize Hyundai will not cover the cost to repair or exchange the engine, I contacted the Hyundai customer service who stated since the repair that is needed wasn't the root cause of the problems associated with the engine swap warranty they were not going to help me even though I explained to them that the cars high accelerating and the braking system been jeopardized and been told the engine is beyond repairs I feel Hyundai should reconsider their decision and help a loyal customer. I have purchased 12 Brand New Hyundaj since 2001. The customer Representative was Extremely un Professional even suggesting I scrap my car, Also I contacted My Hyundai service Technician who said Hyundai customer service never contacted them about my car, When they said they spoke with the technician. Also I received an Extended warranty on the 2.4 GDI engine from Hyundai who many Hyundai customers are or have dealt with.I also purchased an Extended warranty

Since i have owned this car they have replaced the knock sensor twice. there is a recall on the engine for crank bearing wear, my car now is burning through 5 quarts of oil every 2 weeks with no oil leak spots on the ground. i would like them to replace the engine as per the recall. the knock sensor should be an indication of the bearings going bad. i have been getting the run around from the dealer in Salem, Oregon. so, i would like some assistance with this problem thank you for your time.