general problems of the 2020 Hyundai Sonata - part 1

On 2/19/2026 while driving, my 2020 Hyundai Sonata limited 1. 6t began making several loud explosive / popping sounds. At the same time, the fuel gauge on the display screen appeared to rapidly drop, as if the vehicle was losing gas. Immediately following this, the vehicle began to hesitate and lose power while accelerating. The hesitation felt like the engine was misfiring or struggling to maintain consistent performance. There were multiple explosive sounds before and during the hesitation. This created a major safety concern while driving and the vehicle underwent an inspection at Hyundai in deland, FL. The service department was brief and stated they needed to keep the vehicle for repair for an unknown amount of time as the fuel tank expanded. No further information was provided at that time.

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 taken my vehicle to a certified Hyundai dealership multiple times due to intermittent starting issues. The car will unlock remotely, and the lights and electrical components will turn on, but the engine will not start. When this happens, I press the ignition button to turn the vehicle off and then try again. Sometimes it eventually starts, but there have been several occasions when it would not start at all, forcing me to call for a tow or have the battery jumped. This issue occurs most often in cool or cold weather. I had a brand new battery installed at the dealership in July 2025, yet the problem has continued. I have been dealing with this for over a year and have even been stranded out of state in below-freezing temperatures. Each time I bring the vehicle in, the dealership states they are unable to replicate the issue while it is in their service department.

While stopping at a major highway intersection on [xxx] for a red light vehicle stalls and will not start back up while everyone else continues at a 55 mph mile an hour passing me on each side! this happened more than 6 times . While you’re stuck in intersection,you have to keep trying to start the car eventually it will start . Apparently it is egr valve and is a very common problem. It is noted in the common problem for this year making model and the repair cost is in the range of $1600 even the dealership said it is a very common problem. They have been experiencing it. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

My 202 Hyundai Sonata is involved in the current Hyundai fuel system recall. On 10/26/25 the fuel tank expanded and caused three explosive "boom" sounds inside the vehicle while I was driving with passengers. The backseat began heating and rising upward due to fuel tank swelling. The tank became pressurized, hissing, bubbling, and would not accept fuel. The vehicle became inoperable. The car has now been at Hyundai of camelback since 10/27/25 (30 days). Hyndai corporate has repeatedly delayed providing a remedy and keeps telling me they "need another week". I have received no repair plan, and no decision. This violates the requirement for a timely recall remedy. The defect caused structural damage and created a serious safety hazard. ".

My vehicle was at a manufacturer?authorized dealership for a federally mandated recall repair. While the vehicle was in the dealership’s exclusive care, custody, and control, it was struck by a third?party cleaning vendor operating on dealership property and was declared a total loss. I did not hire or authorize this vendor. After the incident, the manufacturer informed me in writing that the dealership would repair the damage at their own expense, separate from the recall work. The manufacturer also stated they were covering the recall?related repairs and were coordinating with the dealership. They provided weekly updates, monitored the recall repair, and escalated a backordered recall part. Later, after the dealership confirmed the vehicle was a total loss, the manufacturer reversed its position and stated it was “not involved. ” the dealership has refused to identify the cleaning company responsible for the loss, their insurer, or any claim information, preventing any direct follow?up. The manufacturer continues to direct me to “work with the parties involved,” even though the responsible vendor has not been disclosed. This raises concerns about the safety and oversight of the recall repair process, the handling of vehicles during recall service, and the manufacturer’s response when a vehicle is destroyed during a recall procedure.

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.

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.

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.

In early may 2025 while driving around 40mph, I heard a very loud pop which startled me. Pulled over and looked back and noticed my backseats were push up out of place. I attempted to put the seat back into place but it wouldn’t fit into the latch anymore. The framing underneath the seats looked pretty damaged so I took it to a local mechanic. After doing some research, he found information for a check valve/fuel tank recall (service campaign 9b1) and then advised me to go a Hyundai dealership. I attempted to take it to the dealership, whom sent me away after I advised them of what happened. I came back the next day asking them to take a look at while informing them about the recall that could be related. Later that evening, they called and said the issue was directly related to the recall and the repairs would be covered. My car was in their possession for from 5. 12. 25 to 7. 25. 25 without any updates or instructions on what is happening. I was told they’re waiting to hear back from Hyundai manufacturer on how to proceed. They returned my car to me on 7. 25. 25 stating everything was repaired. On 7. 31. 25 they called me back stating my tank needs to be replaced and bring the car back ASAP. My car was again being repaired and was returned to me on 8. 25. 25. Now my vehicle will not start randomly sometimes. At this point, I’m under the impression my vehicle is no longer safe as all the issues I’ve been facing are fuel related.

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.

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.

Service campaign 9b1 that my gas tank has explanded/exploded due to the issue noted in the subject line. As you can see the whole bottom of the backseats have been raised up imcluding the part that connects to the gas tank itself. My car is immobilized and not drivable during this time. What is the next step to take?.

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.

Fuel system expanded back seat.

I took my car in for a standard oil change and tune up. They found out that the fuel tank had expanded to the point where it caused significant damage to the metal frame. The Hyundai dealership sent it to the local body shop for an estimate for the frame, they sent it back because the dealership hadn't removed the gas tank, then the dealership sent it back to the body shop. It's been 3+ weeks, my car is still in the shop, and I haven't received any indication of whether my car is able to be fixed. The dashboard never displayed any warning messages and there were no symptoms of the problem. I had no idea the gas tank had expanded and could've caused an explosion or fire.

I took my vehicle in for an oil change and was advised that my car failed a recall. The pcv valve failed. After the dealership, explain this problem to me I no longer feel safe driving this vehicle. Imagine being told that the fuel tank can expand and pop up the backseat of your vehicle at any given moment or even cause the car to blow up and no warning lights coming on to alert you that this part had a defect.

On or about November 13, 2024 our Hyundai Sonata 2020 gas tank almost exploded. We drove our vehicle to a dealership so that it could be checked because we kept hearing something that sounded like a loud pop / thumb underneath our vehicle. We had already been receiving notifications of a powertrain issue with the vehicle for years (without the dealership resolving the issue). So we were taking the vehicle in for numerous reasons when, the minute we drove our vehicle into the service bay (of a new and unrelated dealership) we were told that Hyundai's corporate branch has ordered our vehicle grounded and told us we could not leave with our vehicle or drive our vehicle off the dealership's lot. We were advised that our vehicle had almost exploded and that we were lucky to have brought the vehicle in. We were told that our vehicle should have never left the lot the day we purchased it brand new. We were told that our vehicle's backseats had detached and separated away from the frame of the vehicle. Our vehicle has been at the dealership since the day of the incident (e. G. , on or about November 13, 2024). Our vehicle is still under factory warranty and powertrain warranty and Hyundai was not given us an end in sight or advised the public of the issue with their vehicles. We were told that the vehicles needs repairs such 1. The vehicle needs the fuel tank assy and all of the parts for the tank, check valve, and campaign sticker: please see TSB: 24-01-02oh.

I was driving back from atlanta, GA to pensacola, FL when we noticed our fuel level dropping significantly. We stopped in west point, GA to see what was going on. We turned the car off and back on after 3 minutes and car made a weird vibration. Then the fuel level was rising back to normal but my wife was in the backseat with our [xxx] and she noticed the seat was rising and creating a lot of heat. We pulled over again and noticed it wasn't going down. Luckily there was a mechanic at this gas station and he informed us that the fuel tank expanded and to not drive the vehicle. We we're driving alongside my parents so we got in their car and drove back to pensacola to get a truck and tow attachment cause a tow truck would've costed us $2,500 to tow back to pensacola. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The component that failed is the fuel tank system. While driving, the fuel tank expanded, causing significant damage to the rear section of the vehicle. This issue resulted in the rear seat rising up, and the bottom rear seat cushion detaching from its securing clamps. The check engine light came on, and gas started leaking from the fuel cap. The fuel tank has moved upward by about 3 to 5 inches, no longer resting on the factory fuel tank straps. The sheet metal underneath the rear seat was crumpled, and the fuel pump access cover bent. The vehicle is currently at college park Hyundai and is available for inspection upon request. My safety and the safety of my children were significantly compromised. The loud popping noise startled us, and the fact that the rear seat lifted and detached posed a serious risk to the passengers in the back seat. Additionally, the gas leak created a fire and explosion hazard, putting all occupants of the vehicle and other drivers on the road at serious risk. This incident potentially violates the fuel system integrity (49 cfr 571. 301) regulation, which ensures that a vehicle's fuel system is designed to prevent leaks and fire hazards. Moreover, the unexpected movement and detachment of the rear seat could be a breach of occupant protection (49 cfr 571. 207 and 571. 208), which govern the safety of seating systems and occupant crash protection. The issue has been confirmed by the service center at college park Hyundai, where the vehicle is currently being inspected and evaluated. The vehicle is being inspected by the manufacturer’s authorized service center at college park Hyundai. It has not yet been inspected by police or insurance representatives at this time. The check engine light came on immediately after the loud popping noise and the detachment of the rear seat cushion. Additionally, the gas gauge suddenly dropped to empty after the incident, even though the tank was not empty prior to the malfunction.

I had the check engine light come on about 4 times in my 2020 Hyundai Sonata 1. 6l this year in 2024. I took the car to a technician to get looked at each time it came on. The codes and bulletins kept pointing to fuel system issues. Each time, every service tech said it was a small issue and claimed to fix the issues. The final time a tech seen it lifted the rear seat and found out that the gas tank expanded and the back seat buckled up. The backseat metal frame is bent and messed up. I was flagged down by several drivers ?that noticed gasoline leaking from my driverside rear. My child and I were in dang? er and had to pull on the side of a major highway and stay several hours until someone picked us up. The problem has been confirmed by the hyuandi service center. They said another vehicle experienced this same issue. I was in fear for my life and my child's life because it could have caught fire and/or exploded.

(August 29th) my girlfriend and I were driving in my 2020 Sonata, when the check engine light turned on and my gas gauge dropped from being full to then only half way. About an hour later, driving back home we heard a loud pop as if something exploded. Next day, I took my car to the autonation Hyundai dealership and after taking a look at my car they quoted me about $6,000 to get my fuel tank and charcoal canister replaced. Our safety was put at risk due to the fact that had the damage been any worse, it could have caused the car to possibly explode or give out while driving on the highway, and in turn would put many more lives at risk.

Took a trip to nashville so I left memphis Saturday morning hole on the road heading to nashville I was at least 30 minutes fork the city my car began to jerk very bad suddenly my file light came on so I stopped at a gas station the file light came on telling me I needed gas the had was on the e but my mileage to e said 117miles. So I was like ok that’s weird after I put gas in my car I got back on the road my gas hand went from full to half way and I was not even on the road for 40 minutes so as we get closer to nashville my car starts jerking very bad I hear a noise that sounded like a bag or a piece of paper being crumbled up I turn around to find my rear seat up in the air I knew it was not normal at all looks like it was a lot of pressure for the frame of a car to stand up like that I definitely knew something was wrong when that happened I instantly started to smell gas very loud smell of gas I then start to do my research and I see kia’s and Hyundais are dealing with gas tank expansions so at this point I am scared for my life I’m in my car and I’m dealing with a issue like this. I instantly call my dealership and schedule to have my car towed to the dealership out in nashville. They called me that Monday confirming the gas take had expanded and caused a significant amount of floor damage to my vehicle I am currently waiting trying to see what is Hyundai going to do about this issue that is my only transportation and having to deal with this then find another way back home has been very stressful and just to know that I could have lost my life in that car is even more traumatic.

Fuel tank has expanded to the point that my vehicle is deemed not safe to drive. As pressure in the tank is unable to be stabilized. Only had the car for about 70 days since the date of purchase. Repairs are about $3900. In short as told by the dealership service department, my car could blow up at any time. This is not safe, at all.

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. Kia has acknowledged the issue and did recalls. Hyundai has not. Many owners of the Sonata are having this same exact issue according to reddit posts. I took my vehicle to the dealer, got it diagnosed, was quoted $2900+. I was told it was an extreme safety hazard due to the pressure in the tank and the gas leak. The tank has swollen so much that it’s pressing against the exhaust. I’m out of warranty and they expect me to pay out of pocket. I have no where near $3000. I use my car for work and have no choice but to drive it. Please help.

Gas tank is swelling causing the rear seats to pop up.

What component or system failed or malfunctioned, and is it available for inspection upon request? the fuel tank expanded, was leaking gas from the gas tank opening. The expansion of the tank caused the metal plates/panel under the back seat to popup, where my child sits. Which caused a gap in the door. Ir seepage from the back seat passenger door to where the fuel was leaking out the gas tank and also the fuel gauge on the dash was fluctuating. People on the highway was flagging me to let me know fuel was leaking. The fire department had to come and clear it. How was your safety or the safety of others put at risk? my child and I could have been seriously injured or killed. As well as people on the highway. It could have exploded. You can smell the gas in the car. The gas was coming out the gas tank on the side. Has the problem been reproduced or confirmed by a dealer or independent service center?yes, it was confirmed by Hyundai of north charleston 8485 rivers avenue, north charleston SC, 29406 and it was also checked by the insurance adjustor. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? it was inspected by the insurance representatives state farm were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? no I took it into the dealer and they said it was fixed and it did not fix the gas coming out the tank. And the same issue happened again on August 8 2024.

On July 15th I was driving away from work and my car suddenly stopped accelerating. I was able to get it towed to a body shop I previously had it repaired at. They said the battery system was blowing a fuse when it would become undrivable. They took it to the local Hyundai dealership where they applied a new software update related to the battery management system. This did not solve the issue, it continues to stop while in traffic and the dealership refuses to do anything to figure out the cause.

Riding down the road June 30, 2024 and heard a loud boom coming from the back of my car. I pulled to the side of the road and walked around but saw no damage to outside of car. When I was approximately 30 miles from home my gas started dropping tremendously. Once arriving at home it was a rumble coming from rear of car after inspecting outside car and seeing no damage again, I looked in my back seat and the rear seat was lifted. If my kids or any other occupants would have been back there it could have possibly caused injuries. Upon my mechanic looking my car over they told me it was something to do with my fuel tank. My appointment is July 16, 2024 Hyundai of dothan in dothan al for farther diagnosis. My safety was in danger as explosion from the fuel tank could have cause serious damage and/or injury to car and self. Check engine light came on once the fuel consumption started dropping tremendously.

It looks like the fuel tank has expanded. My back seats are now lifted & will not push down.

I was on my way back home from alexandria la on June 25 2024 when I heard like the sound of an blow out tiire but wasn’t happen to look in back of car and seen back seat was blown off the area of the car and proceeded to see that the gas tank was expanded like you would see a balloon and the me car started running funny and. Then a service code comes across the screen of the radio po45100 , so I pull over and look beneath the car and see that the gas tank is so expanded it’s now pressing against the exhaust pipe. So I turned car off and here we are now I’m without a car due to this.

A week before my gas tank expanding I heard a loud popping noise. When driving from nc to DC, my gas tank refused to take gas and my car immediately went to empty. I was stranding on the highway and has my 2020 Hyundai towed to the Hyundai dealership in chesterfield, va. They told me that my gas tank expanded and my back seats had popped out of place.

Driving 55mph on highway car slows down and make a pop nose and back seat comes up and I start to smell gas.

An independent service center advise us that the gas tank had expanded which could have put my family at risk if exploding or catched on fired. This happend on June 15th 2024 while driving, a sudden explosion coming from the back of the car was heard. Little after the explosion like sound we perceived as if air was coming through the back as if we had a window rolled down. When pulled to check, I notice that the back seat was popped up. No warning on the car was giving prior to the incident. Will take car to Hyundai dealership to have it inspect by them and have a solution.

I have a 2020 Hyundai Sonata sel plus. For the past month I been dealing with my cel regarding fuel tank pressure sensor and I end up replacing one from Hyundai itself. After doing that I notice my fuel tank has expanded and I’m currently dealing with Hyundai & the dealership to see if they can make a recall regarding this issue or just fix it period since it’s a big safety concern. This been happening since mid April. My back seat lifts up from time to time and my fuel pump cover is bent. Below I’ll add some pictures so you guys can see how my tank straps are actually bent which is very uncommon for it to happen. I recently took it to the dealer last week after reaching out to Hyundai corporate and they took pictures and send it for prior approval to see if Hyundai is willing to replace this. I can’t fill up my gas tank, I constantly have to out between $15-$25 the most due to fuel mileage issue since the tank has expanded I get fuel mileage inconsistency.