2020 Hyundai Sonata Problems

What owners report

Owners of the 2020 Sonata report two broad clusters of trouble: a fuel-system problem where the tank swells and fuel leaks or smells strongly in the cabin, and low-mileage drivetrain electronics complaints such as stalling, hesitation, jerking and warning lights on a nearly new car. Rear camera and display failures, water trapped in the rear doors, and a rough-shifting transmission also recur, and the fuel complaints skew toward higher mileage while many others arrive under 20,000 miles.

1. 1
   Fuel system

   Fuel tank swelling and leaking gasoline

   • 30 complaints (16%)
   • median 64,762 mi at 4.8 yrs old (6 state mileage, few)
   • filed 2024–2026

   Owners describe a loud pop or booming sound followed by a strong gasoline smell inside the cabin, a fuel gauge dropping quickly and, in some cases, fuel running out under the car. Several report the fuel tank visibly expanded and pushed up into the rear seat area, and dealers traced it to a failed check or purge valve that lets air and pressure build in the tank. Some say the tank was replaced or the vehicle was held for weeks, and a few report the problem came back after repair. Mostly reported between roughly 40,000 and 110,000 miles; some owners mention a dealer visit for a rear-end noise in the weeks before the leak.

   Recall 25V7960004 related service bulletins

   What to check: Ask whether the check valve and fuel tank were inspected or replaced under the fuel-system service campaign, and smell around the rear seat and filler neck for fuel. A bulging rear seat cushion or a tank that pushes up is a reason to have it looked at.

   2 excerpts from owner complaints in NHTSA records

   “There is an issue with the 2020+ Hyuandai sonatas and Kia K5 models. The valves in my gas tank had failed. Causing pressure and gas vapors to be trapped inside the tank. The pressure in my tank has swollen my gas tank to the point where it’s bent the metal frame underneath my backseat, lifting my backseat off its base. My car is a literal tricking time bomb because the tank will eventually burst. There’s also a strong smell of gas coming from underneath the backseat. There’s been a new story on this issue already. …”

   NHTSA complaint #11612913, filed 2024-09

   “Vehicle subject to NHTSA Recall 25V796000 (fuel system defect). In July 2025, while driving, a loud explosive sound came from the rear of the vehicle followed by raw gasoline fumes entering the cabin. Vehicle was towed to a Hyundai dealership and held approximately 120 days before being returned as repaired. In December 2025, the exact same defect recurred. A third-party diagnostic scan (performed before drop-off) confirmed DTC Code P14EE — Fuel Tank Check Valve / Evaporative Purge System failure — directly related to the recall. …”

   NHTSA complaint #11728980, filed 2026-04
2. 2
   Engine

   Stalling, hesitation and jerking at low mileage

   • 35 complaints (19%)
   • median 2,700 mi at 1.1 yrs old (11 state mileage)
   • 1 mention a crash, fire or injury
   • filed 2020–2026

   Complaints describe the car shutting off or sputtering in traffic, refusing to accelerate normally, and jerking or bucking at low speed. Several owners report a check engine light with a cooling-system or sensor code, and some say dealers could not reproduce the problem or told them nothing was wrong. A few had sensors or an engine replaced and the behavior returned. Frequently reported under about 20,000 miles, though also appearing on higher-mileage cars.

   4 related service bulletins

   What to check: Have a pre-purchase scan done for stored codes, particularly cooling-system and fuel-trim codes, and ask for service records showing whether an engine computer software update or thermal module replacement was performed.

   2 excerpts from owner complaints in NHTSA records

   “Occasionally there is a serious delay when trying to accelerate. Car tends to jerk/buck when accelerating, usually in the lower gears. I have no idea if this is a transmission issue or a fuel injection issue, but my dealership has not been able to detect an issue and keeps telling me everything is normal when it clearly isn't. The car also has harsh downshifts especially going from 2nd to 1st gear.”

   NHTSA complaint #11386446, filed 2021-01, 2,000 miles

   “My car stalled and stuttered between 1000 and 1500 miles in traffic and couldn't get it into gear once started. It was the fuel rail sensor. Now at 6000 miles did same thing. If sits for bit works again. It also reset itself and I lost all preprogrammed information. The gas door also opens at times when unlock driver door. The dealership had it the first time for over 30 days and had to contact engineers to fix it.”

   NHTSA complaint #11360642, filed 2020-09, 1,200 miles
3. 3
   Transmission and drivetrain

   Harsh or delayed shifting and shifter warnings

   • 12 complaints (7%)
   • median 8,349 mi at 1.0 yrs old (6 state mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2020–2025

   Owners report delayed or harsh shifting, especially between lower gears, and a bump or hesitation when pulling away from a stop. Some see a shifter-system or shift-assist warning message and find the gear selector unresponsive, and a few describe the car feeling like it is in a limp mode with limited speed. Reported from a few thousand miles up to the 20,000-40,000 mile range in the sample.

   5 related service bulletins

   What to check: Drive the car from a stop and through low-speed downshifts looking for lurching or delay, and check whether any transmission control module updates were applied.

   2 excerpts from owner complaints in NHTSA records

   “Pushed the park button, showed p on the dash indicator, doors then unlocked. When exited vehicle it began rolling backward, park had not engaged slight hill only. This has happened repeatedly. Pushed button to place the car into reverse and the vehicle would not engage or go anywhere.”

   NHTSA complaint #11363560, filed 2020-10, 500 miles

   “As the vehicle was at a complete stop and waiting for a chance to get in traffic, the car hestiated and would not respond to the depress of the gas pedal, for a second or two... Very strange indeed!....is it a transmission issue or something else....the transmission shifts strange from the complete stop position...this happenes more than once! And one instance it actually jerked ( bucked) somehow...concerned about this...”

   NHTSA complaint #11376745, filed 2020-11, 1,600 miles
4. 4
   Electrical system

   Rearview camera shows a black or blank screen

   Mentioned in 4 of 60 sampled complaints

   Complaints describe the backup camera displaying a black screen, only the guide lines, or a frozen image when reverse is selected. Some owners say it started intermittently and became constant, and a few were told the camera itself was faulty and needed replacement. Reported from roughly 8,000 to 130,000 miles, spread fairly evenly.

   4 related service bulletins

   What to check: Shift into reverse during the test drive and check the image on the screen from cold and after the car has been running; ask whether any infotainment software update has been done.

   2 excerpts from owner complaints in NHTSA records

   “The contact owns a 2020 Hyundai Sonata. While the contact's wife was reversing, the back over prevention camera system displayed a black screen. The dealer was made aware of the failure. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The contact referenced an unknown recall with a similar failure; however, the VIN was not associated. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 46,000.”

   NHTSA complaint #11686955, filed 2025-09, 46,000 miles

   “The contact owns a 2020 Hyundai Sonata. The contact stated that while reversing, the back-over prevention camera malfunctioned, and there was no image of the rear of the vehicle displayed. The contact stated that the display screen only displayed lines. The contact stated that the failure caused a visibility hazard for the driver. The vehicle was examined by an independent mechanic who determined that the camera was faulty and needed to be replaced. The vehicle was not yet repaired. …”

   NHTSA complaint #11696513, filed 2025-10, 130,000 miles
5. 5
   Body and structure

   Water trapped in the rear doors

   • 11 complaints (6%)
   • median 1,727 mi at 1.2 yrs old (6 state mileage, few)
   • filed 2020–2025

   Owners say water collects inside the rear door panels when it rains and pours out when the door is opened, in some cases filling the interior of the door. Complaints describe dealers confirming the issue on multiple cars but being unable to find the entry point or fix it. Reported mostly under about 50,000 miles, often within the first year of ownership.

   What to check: After a rain or a run through a car wash, open and close the rear doors and listen for sloshing or water draining; check the door bottoms for rust or damp carpet.

   2 excerpts from owner complaints in NHTSA records

   “When it rains water gets inside the doors while parked. Especially the back doors. If it rains hard a cup full of water will come out the door upon opening. I've been told it's a design flaw. I've had it looked at twice and it's still not fixed. Customer service can't have someone come out and look and it because of the virus, so there's nothing that they can do.”

   NHTSA complaint #11322889, filed 2020-04, 200 miles

   “Rear doors retain water every time it rains. When you open the rear doors water drains out of the car. Brought car to Hyundai dealership who verified the problem and confirmed the problem with other new cars on their lot, on april 21, 2020. Dealership contacted Hyundai corporate for guidance and there has been no response to date.”

   NHTSA complaint #11326116, filed 2020-05, 520 miles

Buying note. Check the fuel tank recall and service campaign history first, since that is the most frequent and most serious complaint on this year, then verify the backup camera and rear door drainage and scan for stored engine and transmission codes before buying.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.