2020 Hyundai Sonata

Whille driving back to Washington state my car check engine light came on and the car shut off while I was driving. I had to have it towed to the nearest city whi ch was Laramie Wyoming. There is no Hyundai dealer had to drive the car once it started back up to Cheyenne Wyoming it was checked. My on star told me there was a problem DTC P0145100 the status had red triangle the DTC power system powertrain and the DTC sub system EMS. I was told and given paperwork by the dealer and was told the car would need major repairs and could take up to 21 days once the work started it would have to he completed there because Hyundai had campaign dealing with my cars problem. I was told I could drive the car home but if the check engine light is flashing pull over immediately. My car is now at the 3rd dealer when I took it to Korum in Puyallup they did not have anyone to diagnose the vehicle only update onboard computer. They said and documented nothing was wrong with the vehicle which is inaccurate. I told Korum about the paperwork from the dealer in Cheyenne they did not so much as look at it. I took the car to the Dealership in Auburn Washington they to had the same findings as Wyoming also there was additional findings which corresponded with the smell of gas and my tank going empty after filling and trying to fill tank because was showing low fuel warning. Pictures were taken of the gas tank which had expanded as well as other pictures of the findings. I was told in Wyoming and Auburn that the code and findings are consistent with the Hyundai campaign

The HVAC blower motor and related electrical components (including the fuse box, wiring harness, or control module) have malfunctioned. The system either fails to operate entirely or works only on low, with unpredictable surging airflow. These components are still installed in the vehicle and available for inspection upon request. For the past five days, my family has been driving without a functioning air conditioner in extreme Oklahoma summer heat. This is not only uncomfortable but unsafe, especially for my young child who regularly rides in the vehicle. In addition, without reliable airflow, we are unable to defog the windshield in humid conditions, which significantly reduces visibility and increases the risk of a crash. The inability to regulate cabin temperature and airflow poses a serious safety hazard. Yes, the issue has been observed by the dealership during service visits. However, Hyundai has denied goodwill repair assistance and has not formally acknowledged the defect, despite Technical Service Bulletins and numerous similar reports from other owners. Yes, the vehicle has been inspected by an authorized Hyundai dealership as part of a multi-point inspection. No warning lamps or dashboard messages appeared. However, symptoms began nearly a month ago and have persisted, including intermittent blower operation, limited airflow regardless of settings, and occasional surging. While I have not personally noticed a burning smell, I’ve found numerous reports from other 2020–2021 Sonata owners describing complete blower failure and smoke smells, often tied to fuse box or electrical issues.

Something went wrong in the fuel tank that caused it to become so pressurized that the tank expanded up and out so far that it pushed the exhaust pipe down and my back seat of out place. The only issue I had was the car was accelerating slower than usual but it wasn’t even enough of a difference for someone who didn’t drive it every day to be able to tell. It did this for two days then the check engine light came on and it just read “powertrain”. Began slow acceleration on 06.08.2025. Check engine light came on the night of 06.09.2025. I took it to the dealership 06.10.2025. I immediately took it into the dealership and they told me the car could have exploded. There was a previous recall for the fuel pump that I had replaced at the dealership. After seeing my car, they said their techs and the techs at HMA have never seen one this bad and that maybe after replacing the recall part the system update failed in my vehicle and the issue was never actually resolved.

I received a notice in the mail my car needed a software update. I went to the dealership to have the update performed. They informed me there was a service campaign for an expanding fuel tank due to pressure. They were unable to return my car to me at that time stating they were awaiting direction from Hyundai Motor of America for the fix. The fuel tank expanded so much it bent the body of of the car underneath the backseat. It also broke the support straps. The dealership stated it was a known issue with a vent valve. Causing the fuel tank to swell so much it damaged the body. They have had my vehicle for 9 weeks with no direction as to what to next.

It was about 100 degrees outside yesterday, and while trying to pass a car, I look in my rearview mirror and notice there is fuel shooting out from my fill hose under my gas flap. I lost over 3 gallons of fuel on the road. This happened my whole 60 mile trip. This has happened to me before, but the temperature was around 76 degrees and it does not happen in cold weather. I have a feeling my fuel tank is expanding because when I took out my back seat where my fuel tank is located, the body of the car is all buckled up to the point where I can't get my backseat to latch down anymore. My car is available anytime for inspection upon request. I have not taken it to a dealer to get it looked at, there has not been a police report filed. And there were no warning lights or indicators other than a popping sound coming from my backseat area before the problem occurred. There are no warning lights or indicators after the problem either. I feel like I'm driving a bomb because my fuel tank could blow up at any time. This problem can be reproduced anytime by filling the tank and driving it in 90 degree weather.

I experienced an issue where the gas tank in my 2020 Sonata began to swell and emit loud popping noises while the vehicle was parked. I took it to the dealership, and Hyundai corporate eventually acknowledged the issue and agreed to buy out my loan. However, no official recall has been issued for this model year. This problem has had a major impact on my life. I lost my job due to not having transportation for over two months, and the stress of not knowing whether my vehicle was safe made it even worse. I had to upgrade my insurance for a loaner I never received, take financial hits, and go into deeper credit trouble—all while also recovering from a serious injury from a previous car accident. I now have to start over with a new loan while my credit is already damaged. I’m submitting this report not just for myself, but to ensure that other 2020 Sonata owners are protected and made aware of this issue. I believe this is a serious defect that warrants official investigation.

The contact owns a 2020 Hyundai Sonata. The contact stated that after shifting into reverse(R), the back over prevention camera screen temporarily displayed an image before the screen went black. The contact stated that the failure had become a recurring failure, but recently became a constant failure. The contact had not taken the vehicle to a dealer or independent mechanic to be diagnosed or repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 64,000.

So I was driving down the highway and I went to pass a car, (I never get close when passing) I was probably at least a quarter mile away from the car I was passing. I have every safety feature turned off, as I have, since buying the car almost 2 years ago. All of a sudden, I’m not sure if my sensor was off or what, but I’m assuming it thought I was too close to that car and it just started swerving all over the highway. I went left/right 4 times before I was finally able to regain control, I couldn’t couter-act the swerves, nor could I hold my steering wheel straight to stop them. Luckily there were very few people on the highway as it was early in the morning. Had the time of day been different, I probably wouldn’t be here today, and some others probably wouldn’t be either, at least lots of injuries I’m sure. It hasn’t been confirmed, i don’t even know how to do that honestly, I was the only one in the car. I didn’t call anyone/say anything until right now because I was already running late for work, I was shaken up but I just called my parents and they said to look up recalls/file a report, which it seems like this is how I do it? There were no warning signs, nothing, I was driving for already about 30 minutes and everything was fine, never had any issue like this ever before. Like I said I’ve had this car for almost 2 years and she has been an absolute dream, aside from this mishap. But now I am very terrified to drive it, i don’t know what happened honestly, I don’t know what could have caused it, but this is why I hate smart cars. My safety was put at risk by what I assume was a safety feature malfunction of some kind.

My 2020 Hyundai Sonata has a recurring defect in its engine or transmission, causing sudden deceleration to ~10 mph without warning, often on major highways, with warning lights (check engine, ESC, traction control, etc.) flashing seconds before the car decelerates. This forces me to swerve off busy roads, endangering me, my passengers, and other drivers. Near-misses with traffic pose an extreme safety risk, causing significant emotional distress. The car, at a Hyundai dealer since April 21, 2025, is available for NHTSA inspection. The issue began in January 2021, five months after purchase, with all the warning lights appearing during incidents along with rapid deceleration. The Hyundai dealer confirmed the problem in seven repair attempts (January 2021, December 2021, January 2022, November 2024, February 2025, and twice in April 2025) but never properly diagnosed or fixed it, citing no consistent diagnostic codes. Only the dealer assessed it; no inspections by Hyundai’s manufacturer, police, or insurance occurred. In November 2024, the defect recurred immediately after pickup, despite false assurances it was fixed. In February 2025, the dealer kept the car over a month with minimal communication, yet it failed again. I picked up the car on April 4, 2025, but it broke down on April 6, less than 55 hours later. I returned it April 7 and picked it up April 17, and it failed again on April 21, 2025 with the vehicle remaining at the dealer since. The dealer and Hyundai offer no solution and this dangerous issue keeps recurring. Similar NHTSA complaints suggest a broader issue. Rapid recurrences—hours after April 4 and four days after April 17—prove the car is unsafe and assurances of repairs are untrustworthy. I no longer trust the Sonata or Hyundai’s repairs, as the defect persists.

My wife and son experienced a terrible situation on the way home from training. They had to stop at the nearest gas station due to the vehicle showing extremely low gas in the tank during a short drive home. The fuel gauge initially showed about half a tank but drastically dropped on the way home. They stopped at a gas station to add fuel but during the process, fuel starting spewing out of the tank. The vehicle was scheduled to be dropped off at a later date for an open recall (service campaign 9B1). I called the dealership and told them I needed to get the vehicle in right away due to the incident. After bringing the vehicle to hyundai, they told me that the fuel tank exploded causing the tank to swell all the way around. Because the tank is located under the rear seat, we constantly heard air coming in due to the rear seat not seating properly. The check engine also was on and we smelled fuel while driving the vehicle. Hyundai representatives has been avoiding my calls to the point where I had to go in person for an update. Apparently, a district manager had to come inspect the vehicle to advise the dealership how to write up the request to send to corporate.