Most common 2021 Hyundai Sonata Hybrid problems
Share of the 55 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
Hyundai Sonata Hybrid complaints by model year
Best Sonata Hybrid years: 2019, 2018, 2014. Years to avoid: 2021, 2016, 2012. Compare all years →
NHTSA defect investigations
Federal safety investigators have looked into a possible defect involving the 2021 Hyundai Sonata Hybrid:
Pedestrian alert sounds
NHTSA received a petition on or about July 18, 2022, requesting that Federal Motor Vehicle Safety Standard (FMVSS) 141 be applied to all electric and hybrid vehicles operating in the United States. The petition can be reviewed at NHTSA.gov under ODI Number 11486072. FMVSS 141 establishes performance requirements for pedestrian alert sounds for motor vehicles.
What 2021 Hyundai Sonata Hybrid owners say
Electrical system all 25 →
The contact owns a 2021 Hyundai Sonata Hybrid. The contact stated that the key fob was inoperable and after using the key to manually open the door. The contact stated that the vehicle failed to start while pressing the START/STOP button. The vehicle was towed to the local dealer, but the cause of the failure was not determined. The contact was advised that when the failure occurred, to start the vehicle, the battery reset button should be pressed before pressing the START/STOP button. The manufacturer was not contacted regarding the failure. The failure mileage was 24,000.
On Wednesday, October 6th, I was driving full speed (65mph) on a major highway. Multiple lights on the dashboard came on. The LCD display screen for music, apps, etc. went black. More lights came on and others went off on the dash display. I let off the accelerator and steered the car. The fuel efficiency was wilding jumping back and forth. Soon enough, all the lights went back off, but the mileage gauge (fuel efficiency) continued to jump wildly. The brakes seemed to respond differently- almost as if there was a delay between me pressing the brake and the brakes catching. When I needed to accelerate, the car seemed to be having trouble switching between the electric and gas motors. I was able to drive to a safe location and shut the car off. This was terrifying, as the car's computer system or electrical system clearly failed, even if temporarily. …
Engine & cooling all 24 →
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. …
Fuel & propulsion system
The vehicle was brought to an authorized Hyundai dealer to have Service Campaign TBH and 94B completed. These campaigns were explicitly designed to prevent known mechanical defects (cracked EHRS assemblies and high-voltage battery errors). The software patches failed to protect the vehicle. The physical hardware has now catastrophically failed exactly as predicted by the campaign, resulting in extreme engine overheating and a physically swollen high-voltage battery pack. Hyundai is refusing to cover the cascading physical damage caused by their own failed campaign remedy, leaving me with an active safety and fire hazard. FUEL/PROPULSION SYSTEM" and explicitly state that the vehicle experienced an unchecked thermal event due to an ineffective corporate software update (Campaign TBH / 94B). All documents I have supporting this will not fit in this upload limit.
When I arrived in the parking lot and selected the R (reverse), the vehicle stayed in the D (Drive) although that it was moving backwards and was able to park it. The shift selector was stuck in DRIVE (Drive) leaving the vehicle on but not operational. After several attempts to allow the vehicle to cool and the battery to reset, (30 minutes_ later), the car started and took the vehicle to be serviced. The vehicle technician said they had a difficult time diagnosing the vehicle because it was giving different codes. They said that while testing they found the Transmission Shift Selector Module was damaged. Not physically but electronically damaged. They also stated that the car could have other problems but that they needed to replace the module first because it could be the cause of the other errors.
2021 Hyundai Sonata Hybrid engines & fuel economy
| Engine | Transmission | Drive | MPG city / hwy / combined |
|---|---|---|---|
| 2.0L 4-cyl hybrid | 6-speed dual-clutch | FWD | 45 / 51 / 47 |
EPA ratings. Class: Large car.
Frequently asked questions
Is the 2021 Hyundai Sonata Hybrid a good car?
Based on 55 owner complaints filed with NHTSA, the 2021 Sonata Hybrid rates use caution: 1.9× as many complaints as a typical year of the Sonata Hybrid at the same age. It is one of the Sonata Hybrid years we suggest avoiding. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2021 Hyundai Sonata Hybrid?
The electrical system — 25 complaints, 45% of all complaints for this model year, most often about 12v/24v/48v battery. Next are the engine & cooling (24) and fuel & propulsion system (5).
How many recalls does the 2021 Hyundai Sonata Hybrid have?
NHTSA lists no recalls for the 2021 Hyundai Sonata Hybrid. You can still confirm with your VIN using our VIN recall check.
What are the best and worst years of the Hyundai Sonata Hybrid?
The best years by complaints, compared at the same age, are 2019, 2018 and 2014. Years to avoid or approach with caution: 2021, 2016 and 2012. See the full Hyundai Sonata Hybrid years comparison.
At what mileage do 2021 Hyundai Sonata Hybrid problems happen?
The median mileage reported in complaints is about 33,000 miles; 100% of problems with a recorded mileage started before 50,000 miles.
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.