Engine complaints by model year
| Year | Complaints | Share of year's complaints | Typical mileage |
|---|---|---|---|
| 2024 | 1 | 11% | 15,000 miles |
| 2023 | 7 | 47% | 34,000 miles |
| 2022 | 2 | 11% | — |
| 2021 | 24 | 44% | 33,000 miles |
| 2020 | 8 | 50% | — |
| 2019 | 3 | 60% | — |
| 2018 | 5 | 56% | 75,000 miles |
| 2017 | 50 | 62% | 80,000 miles |
| 2016 | 76 | 57% | 85,000 miles |
| 2015 | 21 | 39% | 75,000 miles |
| 2014 | 13 | 46% | 80,000 miles |
| 2013 | 41 | 38% | 91,000 miles |
| 2012 | 70 | 45% | 97,000 miles |
| 2011 | 41 | 43% | 102,000 miles |
Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
What owners report
The contact owns a 2023 Hyundai Sonata. The contact stated that while driving 75 MPH, the vehicle briefly lost motive power before downshifting to a lower gear. In addition, the engine revved independently. The contact was able to pull over to the side of the road and turned off the vehicle. The contact was able to restart the vehicle; however, the vehicle failed to exceed 60 MPH. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The failure persisted, and the vehicle was no longer being driven. The contact parked the vehicle at the residence. The contact started the vehicle and the check engine warning light illuminated. The manufacturer was not notified of the failure. The failure mileage was approximately 34,000.
UNKNOWN- While driving on highway, from 70 mph speed the car suddenly lost acceleration and speed dropped. No response to accelerator. Even with pushing the accelerator high, car will go in high RPM and speed will barely reach 40 mph. I was lucky that there was no other vehicle behind me, especially heavy automobile like semi truck as it would have crashed in me from behind due to sudden propulsion loss. The car started working fine next day. I took it to dealer and they couldn't find any error code but said it could be 12V battery BMS software update and they updated it. They mentioned that this is NOT a safety issue which is mind-blowing and concerning as this is a MAJOR safety hazard. I would request you to investigate this further and if this is a software issue then please direct Hyundai to update this with all vehicles and cover the cost for those who have had to pay for it.
The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, he received an alert indicating that the engine was overheating and to pull over. No warning lights were illuminated. The contact then veered to the side of the road and waited approximately 15 minutes before restarting the vehicle. The vehicle was then taken to the dealer where the vehicle remained. The vehicle was diagnosed, and it was determined that the engine coolant bypass valve needed to be replaced. The vehicle had not yet been repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 32,547.
My 2021 Hyundai Sonata Hybrid seems to be leaking coolant into the exhaust system. Various reports online indicate that this is a consistent issue with 2020-2022 Hyundai Sonata Hybrid models. A lot of the reports indicate that owners have tried getting theirs cars repaired for the same issue I have a various dealerships all across the US, but either haven't had any luck or have had a temporary fix for the issue, which proceeded to occur again every couple of months. I personally have had my car inspected by my personal dealership and they have confirmed the issue and have mentioned that other owners have brought theirs in to be checked out, but haven't really had luck. I believe that Hyundai should take responsibility for this and issue a recall on the affected models. …
I noticed a strange smell almost like burning maple syrup in the garage for months. I thought it was just a different smell from Hybrid cars as I didn't have this used car very long. While driving at times the acceleration would stutter, again I thought this was just expected having never driven a hybrid car. Then on a trip a couple hours out of town someone stopped me on the road to tell me I was burning antifreeze and he could see white smoke coming from the car. I pulled over and didn't notice anything and continued driving but the heater wasn't working, it was blowing cool air despite the heat being on. I pulled into an auto parts store and got antifreeze in case. And then the overheating alert came on. I waited and filled it up and made an appointment at the dealer. They diagnosed it as a a blown gasket and a bad catalytic convertor and replaced all of that. …
I went to work at 5 in the morning, I turned the heater for the first time after last winter. I noticed that the heater was struggling to warm the cabin. After 10 minutes driven I got an overheating alert on the dashboard. I pulled over on the freeway shoulder and it started to notice a lot of steam coming from the exhaust and a really strong coolant smell. I waited for the engine to cool down and went back home, I drove for 6 minutes and notice a huge amount of smoke coming from the exhaust I pulled over agin on the freeway and waited 20 minutes i finally arrived home and notice the coolant reservoir was empty since the car was burning all the coolant through the exhaust. I went online and saw many many people with Hybrid sonatas complaining about the same issue. This should be a massive recall many of the customers complaining had 20 to 50 thousand miles on their vehicle. …
Purchased 2019 after 44,000 miles engine was replaced metal in engine and inverter coolant issue July 2025 117,000 my inverter coolant light came in and off several times then car through all warning lights hev check engine warning shut it down went into limp mode Towed to dealership they checked and cleared codes said it threw 13 codes but after clearing they stated nothing wrong with it As they went to pull car around it happened again this time code was knock sensor which they relaxed at no charge extended warranty They next day after picking up while at idle hev warning went in shut car off and it was gone kept driving nonissues The next day again it happened and this time the engine light stayed on Spoke with dealership they said they would charge me diagnosis charge of 208 and if it was related to what they did. …
am writing regarding 43099808 Number with Hyundai My 2019 Sonata hybird se in limp mode with an active flashing P1326 knock sensor code. The dealership is using an automated system denial to try and charge me $2,110 for an EGR valve and air filter.I am officially challenging this diagnostic path. Mathematically and mechanically, an EGR valve or MAF sensor cannot generate the structural rod-bearing acoustic frequency required to trip a manufacturer-specific P1326 engine protection code.Furthermore, the tracy Hyundai certified my vehicle's warranty compliance and replaced my knock sensors under the KSDS campaign only two weeks ago. The fact that the P1326 code flashed again 14 days later proves the new sensor is successfully detecting an internal structural engine failure. …
Related recalls (2)
Engine
Hyundai Motor America (Hyundai) is recalling certain 2017 Tucson and Sonata Hybrid vehicles. The connecting rod bearings inside the engine may wear prematurely, which can result in engine damage.
Remedy: Dealers will inspect the engine. If bearing damage is found, the engine will be replaced. Dealers will also install a software update containing a new Knock Sensor Detection System (KSDS).
Engine
Hyundai Motor America (Hyundai) is recalling certain 2015-2016 Veloster, 2012 Santa Fe, 2011-2013 Sonata Hybrid, and 2016 Sonata Hybrid vehicles. The connecting rod bearings inside the engine may wear prematurely, which over time can result in engine damage.
Remedy: Hyundai will notify owners, and dealers will inspect the engine. If bearing damage is found, the engine will be replaced. Dealers will also install a software update containing a new Knock Sensor Detection System…
NHTSA investigations
Engine Fires
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.
Loss of Motive Power
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.
Frequently asked questions
Which Hyundai Sonata Hybrid years have engine problems?
By NHTSA complaints, the 2016 (76), 2012 (70), 2017 (50), 2011 (41) and 2013 (41) model years. Engine complaints make up 57% of all complaints for the 2016.
Is there a recall for Hyundai Sonata Hybrid engine problems?
Yes — 2 recalls, including 21V-727 (engine, Sep 17, 2021); 20V-746 (engine, Dec 1, 2020). Recall repairs are free at authorized dealers; check a specific car with the VIN recall check.
At what mileage do Hyundai Sonata Hybrid engine problems start?
Across all years, half of the complaints with a recorded mileage happened before about 90,000 miles; 20% happened before 50,000 miles.
What part fails most often?
Owners most often name the exhaust system › emission control › catalytic convertor (2 mentions), followed by the engine › engine control module (ecu/ecm) › software (1).
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.