Vehicle experienced intermittent, severe powertrain defect resulting in a critical safety hazard. Between 30K and 36K miles, the vehicle underwent 3 violent highway deceleration episodes. During these events, the engine began shaking, escalating to violent shaking; with deceleration and coming to a stop, it would shake, then sputter as if it would die. Coming to a complete stop, a total stall was prevented only by the ECM forcing a limp mode lock at 1200 RPMs. When Auto Hold was engaged at this point and my foot was removed from the brake pedal, the mechanical surge caused the vehicle to unexpectedly lurch forward, fighting against and nearly overriding the factory Auto Hold braking safety feature before finally holding. Luckily, no pedestrian was walking in front of my car when this occurred. No check engine light (CEL) or dashboard warning ever illuminated. This safety compromise is directly tied to an ineffective or adjacent remedy involving Service Campaign 9B1 (Opcode 40D219R0) and Safety Recall 286. Under this Opcode, a factory software flash deleted the standard OBD-II trouble code P0451and substituted it with a manufacturer-specific shadow code P14EE00. This software manipulation suppressed universal emission/pressure sensor faults, masking a volatile physical defect within the high pressure fuel delivery and ignition systems. Dealer diagnostics on a running, compromised engine flagged an improper fuel injector pulse and subsequently a failing Cylinder 3 ignition coil. All four injectors were replaced but only one coil, leaving 3 non-updated , factory defective coils in the engine. The vehicle remains an ongoing highway stalling and brake-override hazard due to an incomplete field remedy of a recall-adjacent system. I've filed a Hyundai Complaint with assigned case number 43394228 regarding Safety Recall 286. (Two episodes of the attempted Auto Hold override occurred - first 09/09/2026 and second 09/29/2026.)
2020 Hyundai Sonata engine problems
32 complaints (17% of all complaints for this car). Typical mileage when it fails: 47,000. 1 crash reported.
- owner complaints
- 32
- of this car's complaints
- 17%
- typical mileage
- 47,000
- crashes
- 1
- recalls
- 0
Which part fails
Owners did not name a specific part.
At what mileage
Complaints by mileage at the time of the problem.
Hyundai Sonata engine problems in other years
Specific symptoms reported on the 2020 Hyundai Sonata engine
Phrases found in the owners' own descriptions, so one complaint can mention several symptoms.
Check engine light 32Stalling 11Overheating 7Loss of power 6
Related recalls
No recalls on record for this model year.
Related investigations
Loss of Motive Power
the federal safety agency 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 complaints were provided which alleged that the oil drain pans lack sufficient structural integrity and are susceptible to cracking. The petition itself can be reviewed at under ODI number 11481745. On September 12, 2022, the Office of Defects Investigation (ODI) opened Defect Petition (DP22-003) to evaluate the Petitionersâ request. The Petitioners have provided additional complaints within four supplemental letters dated January 31, 2023, March 21, 2023, May 23, 2023, and August 4, 2023. ODIâs evaluation included the review and analysis of the complaints and supporting information submitted by the Petitioners, as well as additional complaints submitted directly to the federal safety agency which referenced either the oil drain plug or a crack in the oil pan. After reviewing the available data, ODI has not identified evidence that would support opening a defect investigation into the oil drain pan assemblies of the subject vehicles. Based on a review of the available information, a loss of motive power resulting from an oil drain plug back out has not occurred between the initial sale of a vehicle and the completion of its first oil change. If during an oil change service, a technician fails to remove the existing drain plug gasket before installing a new gasket, it is likely that a proper seal between the drain plug and the oil pan will not be made. An improper seal between the drain plug and oil pan could lead to the backing out on the drain plug, resulting in the sudden loss of oil while driving. Additionally, the provided examples of oil pan cracks were localized to the immediate vicinity of the oil drain plug and/or appeared to be the result of direct-contact with a tool during servicing. Â There is no information to support that a vehicle-based defect exists relating to the oil pan assembly, and instead the documented incidents are related to the failure to follow the proper maintenance procedures during oil change service. In October 2023, Hyundai published a Technical Service Bulletin (TSB) that provided detailed instructions for oil change service on its gasoline powered vehicles, specifically highlighting the need to remove and replace the existing drain plug gasket prior to reinstalling the drain plug. After a thorough review of the material submitted by the petitioner, the information already in the federal safety agency's possession, and the potential risks to motor vehicle safety implicated by the petitioners' allegations, the federal safety agency does not believe that a formal investigation is warranted. Therefore, the petition is denied. A Federal Register Notice (FRN) further detailing the federal safety agencyâs reasons for denial of the petition will be published. The reference numbers for the complaints to the federal safety agency cited by the petitioner can be found in the petition submission documents in the public file for DP22-003. To review those complaints and the additional complaints ODI added to its evaluation which are cited in the Closing Resume ODI Report Identification Number document, go to
DP22003
What 2020 Hyundai Sonata owners say
Most recent owner complaints, unedited.
The A/C evaporator core and the core seal needs replacing on 2020 Hyundai Sonata. Car is 6 years old. I already have a confirmed diagnosis with a PPM refrigerant leak tester at the condensate drain line The diagnosis is 100% confirmed. The evaporator is leaking heavily—we pulled 274 PPM at the drain tube and 177 PPM inside the cabin behind the glove box so refrigerent has been leaking out of the vents. My wife and I were getting headaches for no reason. Our AC has failed and this problem was discovered as the issue and I am paying out of pocket to fix something that should not have failed and has leaked out refrigerent.
My vehicle while driving, it is jerking and shaking. When I come to a stop, the cars rpms go up and down while the car is shaking. When I pressed the gas pedal to accelerate the car will not accelerate as normal and the car jerks as I’m driving it. The RPMs rev up and down without any pressure placed on the gas pedal. The check engine light came on.The miles per hour only allows me to put one digit. I wanted to clarify that the problem is occurring anywhere between 0 mph to 65 mph when these the car jerks and shakes and the RPMs go up and down without me pressure on the gas pedal.
The contact owns a 2020 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the low oil warning light illuminated. The contact added oil to the engine. The dealer was made aware of the failure. The vehicle was taken to the dealer several times, and several oil consumption tests were performed. The contact was informed that the oil consumption test results did not indicate excessive oil consumption. The failure reoccurred. The vehicle was taken to the dealer, and the contact was informed that the oil level was a half quart low. The contact was informed that no repair options were available. The manufacturer was not made aware of the failure. The failure mileage was approximately 80,000.
My 2020 Hyundai Sonata 2.5L is experiencing excessive engine oil consumption. At approximately 88,063 miles, Great Lakes Hyundai documented that the engine oil level was 1.30 quarts below full after an oil-consumption check. The dealer topped off the oil, submitted photos and a prior-authorization/goodwill request to Hyundai, and Hyundai declined assistance. The dealer recommended combustion chamber cleaning with an estimate of $979.76. I am concerned that this excessive oil consumption could lead to sudden engine damage, loss of power, stalling, or engine failure if the oil level drops between checks. The vehicle is only a 2020 model year, and this level of oil consumption appears abnormal. I am also concerned about possible emissions/catalytic converter damage from oil burning.
For my vehicle the Check Engine light has been on continuously throughout the last 6 months and mechanics are going to have to replace the thermostat. Multiple auto mechanics have indicated online that this is a very common problem with many Hyundai vehicles from 2020-2023 and can be a danger due to temperature control not being accurate for vehicles (Code P2181). Many owners of these Hyundai vehicles have experienced this issue leading online and this issue should be made aware to Hyundai and the general public to see if this is something that needs to be made aware for the safety of drivers to determine if their vehicle is at an accurate temperature.
2020 Hyundai Sonata SEL Plus, VIN [XXX] . A/C system fails due to refrigerant leak that empties the system completely within 1-2 weeks of recharge. Leak cannot be located through standard external inspection. First noticed reduced cooling summer 2025. Driver's side loses cooling first, then passenger side fails days later — pattern consistent with evaporator core leak in dual-zone system. In September 2025, independent shop found system completely empty, recharged it, and attempted leak detection but could not locate source. Approximately two weeks later, system was empty again. Shop still unable to find leak. Symptom pattern — rapid total refrigerant loss, asymmetric failure (driver side before passenger), no externally detectable leak — points to evaporator core, which is enclosed in the HVAC housing behind the dashboard and invisible during standard inspection. Vehicle has 50,125 miles, still under the 60,000-mile warranty limit after 6+ years. Low-use vehicle averaging under 8,000 miles/year. 5-year calendar warranty expired approx. Jan 2025; issue first documented Sept 2025, only 8 months later. Defect was almost certainly present before warranty expiration. A class action investigation is underway (XXX) for premature A/C failures in 2018-2022 Sonata, Elantra, Palisade, Santa Fe, and Tucson vehicles. Loss of A/C in Texas climate poses risk of heat illness to occupants, especially children. This component should not fail at under 50,000 miles. Original lessee and purchaser; vehicle well maintained. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
The contact owns a 2020 Hyundai Sonata. The contact stated that the fuel failed to go into the tank. The seat failed to move. The engine light illuminated. The vehicle stalled. While driving, the fuel gauge went from full to empty. The contact received the federal safety agency Campaign Number: 25V796000 (Fuel System, Gasoline) after the failure. The vehicle was towed to the local where it was diagnosed that the fuel tank had expanded. The vehicle was repaired approximately eight months later. The contact called another local dealer. Ourisman Hyundai Bowie, 2404 Crain Hwy A, Bowie, MD 20716, who was unable to schedule an appointment. The manufacturer instructed the dealer to keep the vehicle due to it being a fire risk. The manufacturer was contacted regarding a buyback. The failure mileage was approximately 80,000.
It was smoking from the engine, I immediately stopped the vehicle. My safety was put at risk immediately while being in the vehicle when the air bags deployed hitting me in the face and causing my face to swell. The safety of others was put at risk due to others being right next to me and putting others at risk of engine blowing up. Yes, the vehicle has been inspected by police. There were no warning signs on the vehicle.
I have had my car since January of 2023 and I have had no significant issues. I bought the car with roughly 30,000 miles, fast forward to February of 2026 it has about 123,000 miles and the engine is burning oil very fast. My car loses oil so fast the oil light comes on way early before my next oil change is due.
Questions about the 2020 Hyundai Sonata engine
Does the 2020 Hyundai Sonata have engine problems?
Owners have filed 32 complaints about the engine of the 2020 Hyundai Sonata, 17% of all its complaints.
At what mileage do 2020 Hyundai Sonata engine problems start?
The typical (median) mileage in owner complaints is 47,000 miles.
Was there a recall on the 2020 Hyundai Sonata engine?
There is no recall for this problem on this model year.
What year does the Hyundai Sonata have bad engine?
The Hyundai Sonata model years with the most engine complaints are 2011 (1,012 complaints), 2013 (778 complaints) and 2015 (650 complaints).
Other 2020 Hyundai Sonata problems
Fuel system 59Electrical 41Transmission 24Driver assistance 22Body 17Seats 16Acceleration 7Airbags 7Steering 7Visibility 7Brakes 4Lights 2Wheels 2Locks 1Seat belts 1
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