2021 Hyundai Sonata fuel system problems

FUEL/PROPULSION SYSTEM

I took my vehicle in for the safety recall due to an expanding fuel tank on 08/03/2026. I received my vehicle back on 8/12/2026. Hyundai performed an improper repair on the vehicle that will not correct the fuel tank expansion. They replaced the same check valve that was replaced last time I brought the vehicle in for recall on 11/20/2024 repair order # 107221 at Jones Hyundai of Belair. This valve did not and will not correct the fuel tank expansion issue. The expansion issue is caused by fuel getting past the check valve and entering the purge control system. The correct repair is to replace the fuel tank and the purge control system, as the check valve has already allowed fuel to bypass it and enter the system causing the expansion issue. . Replacing the valve that failed & allowed fuel into the system & caused the tank to expand will not correct the issue caused by the failed valve. My fuel tank has not decompressed. I still have the same problem I brought the vehicle in for because the repair Hyundai advised NHTSA on was NOT performed.

NHTSA complaint #11757244 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

Gas tank expansion and pcv melted. Car smells like gas when I was driving earlier, and my garage was flooded with the fumes of gasoline.

NHTSA complaint #11755570 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the fuel gauge indicated that the tank was half full. The contact stated that the gauge erroneously indicated that the tank was empty, and the check engine warning light was illuminated. The vehicle was driven to the gas station, and while attempting to refuel the vehicle, the fuel did not go into the tank. The vehicle was towed to the residence. The vehicle was later towed to the dealer, where it was diagnosed with a failed fuel system and a failed fuel tank. The contact was informed that the fuel system and fuel tank needed to be replaced. The vehicle was not repaired. The contact was informed that the failure was associated with the unrepaired recall. The contact was informed that the vehicle was a fire risk. In addition, the contact was informed that there was a hole in the fuel tank that caused the fuel to leak out of the fuel tank. The contact was informed that the parts were ordered to repair the vehicle. The contact received notification of NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline). The manufacturer was not made aware of the failure. The failure mileage was approximately 50,200.

NHTSA complaint #11754791 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign Number: 25V796000 (FUEL SYSTEM, GASOLINE); however, the part to do the recall repair was unavailable. The local dealer was contacted, and it was confirmed that the part was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The vehicle was taken to the local dealer, and the contact was informed that the fuel tank was swollen and needed to be replaced. The vehicle was not yet repaired. The failure mileage was 80,484.

NHTSA complaint #11753027 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

Engine revving at a complete stop. Surging engine while braking. I was forced to put into neutral when stopping. I had check engine prior that read P049D85. It went away. The Hyundai dealer said to be the EGR valve. Nick Hayes at D'Arcy Hyundai and Hyundai Motor America (HMA) agreeing to a 75% goodwill split of cost to repair.

NHTSA complaint #11753130 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

At approximately 130,000 miles, vehicle developed and internal coolant leak caused by a failed Exhaust Heat Recovery System (EHRS) in the center muffler assembly, matching TSB 23-EM-009H - a known manufacturing defect documented by Hyundai. Coolant has been slowly leaking internally into the exhaust system. The authorized Hyundai dealership initially failed to diagnose the internal leak and told me there was no leak and wanted to send me home. After pushing back, the internal leak was confirmed. If not caught, this defect could result in engine overheating or complete engine failure without warning. Hyundai Motor America has denied goodwill coverage despite this being a documented manufacturing defect.

NHTSA complaint #11746137 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

I took my car to dealer to repair recall. Dealer told me if it failed they would keep car and report stolen if I tried to take it. They failed it. I didn't trust them based on their report it stolen statement. I had the police get my car back. I took it to another dealer where it passed recall easily. I believe they wanted my car for a customer, and tried to get away with this ruse.

NHTSA complaint #11739443 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. The contact stated while driving at an undisclosed speed, the engine shuddered and the engine stalled. In addition, the engine seized. No warning lights were illuminated. The contact stated that the vehicle was seized in the middle of the road. The contact stated that while attempting to start the vehicle, the vehicle started. The failure reoccurred. The vehicle was towed to the residence. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure. The failure mileage was approximately 140,000.

NHTSA complaint #11738864 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

I was notified of a recall on my from vehicle by Hyundai via email some time in March of 2026. The message said mentioned my vehicle may have a defective/worn purge control check valve that would cause the fuel tank to deform. Potentially leading to a release of fuel over time, which then could ignite. NHTSA Recall #25V796000 My car showed now signs of problems, but I brought it into a Hyundai dealership on March 13th where they confirmed my vehicle had the issue. They said the situation required I not drive my vehicle and gave me a rental in the meantime. I assumed it would be a simple swap of the fuel tank and everything would be fine. I was offered a buyback from my Hyundai claims manager over the situation, but I figured since its a simple fix, I'd keep my car and have it fixed. Two weeks went by with no update from the dealership, so I walked in for answers. Turns out, the subframe of my car has been damaged by the expanding fuel tank and they are still waiting for updates from Hyundai on how to proceed as they themselves don't know how to fix my vehicle. My Hyundai claims manager did not mention this when we talked over the phone and he offered a buyback. None of their recall notices mention structural damage anywhere or even as a possibility. I asked the dealership again on April 1, 2026, and they are still waiting on guidance on how to proceed. Neither does my Hyundai claims manager handling this situation on their end.

NHTSA complaint #11729119 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

The internal core of the Exhaust Heat Recovery System (EHRS), part of the center muffler/front pipe assembly (#28600-L5210), suffered a catastrophic failure. This allowed approximately 9 gallons of engine coolant to leak directly into the hot exhaust stream. Safety Risk: This failure creates a severe visibility hazard. During acceleration from stop lights and stop signs, the vehicle emits massive, thick clouds of white glycol smoke. The smoke is so dense that it completely obscures the driver's view of trailing vehicles and prevents following drivers from seeing the roadway or my vehicle's brake lights, creating a high risk of rear-end collisions. Additionally, the rapid loss of coolant caused the engine to overheat and lose power while in motion, nearly causing a stall in active traffic. Confirmation: The failure was confirmed by the service department at Washington Hyundai (Invoice #174281). This is the second failure of this specific component (previously failed in Jan 2025). The manufacturer issued TSB 23-EM-009H for this defect, acknowledging it affects 2020-2023 Sonata Hybrids, but no safety recall has been issued. Symptoms: The issue was preceded by a "sweet" burning smell and a sudden "Engine Overheating" warning on the dashboard. The failed component has been replaced by the dealer, but the manufacturer refused to replace the coolant-poisoned Oxygen (O2) sensors, leaving the vehicle in a technically compromised state. The failed unit is likely held by the dealer for warranty parts return.

NHTSA complaint #11727380 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline); and the vehicle was taken to the dealer for the recall repair; however, the dealer informed the contact that the vehicle was unrepairable, and there was no further information provided. The manufacturer was made aware of the issue, and a case was filed. The manufacturer informed the contact that the field engineers had reviewed the vehicle and advised that a buyback was the best option. Additionally, the manufacturer offered an 8 percent discount on the purchase of a new vehicle. The contact declined the offer because the vehicle had not experienced a failure, and the vehicle would be paid off after two additional payments.

NHTSA complaint #11725496 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The vehicle was driven to the shoulder of the road. The contact stated that the fuel level indicated empty, and the low fuel warning light was illuminated. The passenger seated in the rear seat noticed that the rear seat was out of place and that the seat was very hot. The vehicle was refueled prior to the failure. The contact and the other occupants in the vehicle exited the vehicle. The vehicle was towed to the residence. The dealer was made aware of the failure. The contact was informed that the failure was like the failure listed in NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline). The contact was unaware of the open recall because a recall notification was not received. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 130,000.

NHTSA complaint #11721548 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. The contact received notification of NHTSA Campaign Number: 25V796000 (FUEL SYSTEM, GASOLINE); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure.

NHTSA complaint #11720224 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

On i believe 1/14/26, my check engine light came on. Scheduled appt.for 1/16/26 for diagnostic. Several things were wrong. I decided to come back due to not having the money at the time. Over the wked, I remembered a recall notice i received around November that I asked about in November during my oil change & was told the parts aren't in & they'd give me a call. Upon viewing the recall it seemed some things I was told on 1/16/26 could be a result of the recall. I called my service person Linda on 1/20/26, she spoke to her supervisor & they informed me some of the issues seem to stem from the recall. Linda gave me the manufacturer recall contact information. I contacted them on 1/20/26. She explained there was indeed a recall, there wasn't a remedy yet, it was safe to drive & if something changes, to call back. On 1/28/26 around 5:30am I left home for work & my car all of a sudden experienced a loss of power. It wouldn't go past 30mph. I returned back home & called out of work. I called the manufacturer recall & informed them. She made an appt. to take my car in the follow day, 1/29/26. I decided to drop it off that same day, 1/28/26. I had someone follow me being i could only go 30mph on a flat road & 10mph on a slight hill. I found out my service person Linda was no longer employeed there. I spoke with another employee. He said they would have to do another diagnostic. I left my car. I called the dealership on 1/29/26 for an update, they had not looked at my car. I called the manufacturer recall, they assigned a case manger to my case. Jay from the NCA, called me on 1/30/26 I believe. We've communicated several times without me receiving a adequate update. He's saying the issue seems to be steamed from the recall, there is now remedy yet, & they are still investigating. I've been without a car since 1/28/26, still making payments, missing work, haven't been offered a loaner & have no idea when or if I will get my car back.

NHTSA complaint #11719681 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. While driving at various speeds, the vehicle unexpectedly shut off without warning. There was an abnormal popping sound coming from the vehicle with an abnormally strong fuel odor inside the vehicle. The contact stated that the vehicle was consuming an excessive amount of fuel. The contact received notification of NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline); however, the part to do the recall repair was not yet available. The local dealer and the manufacturer were not notified of the failure. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The failure mileage was approximately 70,000.

NHTSA complaint #11716730 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE

The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. In addition, the contact stated that the vehicle was shaking abnormally. The vehicle was taken to the dealer; however, the contact was informed that the part was not available to repair the vehicle. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The contact received notification of NHTSA Campaign Number: 25V796000 (Fuel System, Gasoline); however, the part was not available for the recall repair. The manufacturer was made aware of the failure, and a case was filed. The failure mileage was approximately 92,000.

NHTSA complaint #11716213 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

I took my car to the dealer on [XXX] with concerns about the strong gas smell that I have been smelling. The Hyundai dealership kept my car for 3 days and stated they could not smell the gas after driving the vehicle themselves. They did repair a cracked cylinder head however they did tell me that it wouldn't have been the cause of the fuel smell. They stated next time I am out driving, and I notice the smell to "pop" into the dealership to have it checked again. While this is good in theory, it is not something I am just able to do. I am [XXX], one of which is still in a car seat and unable to unbuckle themselves to get out if something terrible like a fire was to arise. This was the 2nd time taking my car in, as it was previously fixed in Feb 2025 due to another recall on the gas tank expanding. I do not feel safe transporting my children in a vehicle that is still reeking of gas and a possible hire hazard with no resolution. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA complaint #11712843 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

I was driving my 2021 Hyundai Sonata at approximately 3:00 AM when the vehicle suddenly began shaking and vibrating. While stopped at a traffic light, the check engine light illuminated, and the engine was shaking severely. I immediately pulled over and shut off the engine. After waiting approximately one hour, I restarted the vehicle, but it was only able to drive very slowly. The following day, the vehicle was towed to a local repair shop. Diagnostic testing showed a cylinder 3 misfire, along with EVAP system errors and faulty fuel injector issues. This failure occurred without warning and created a potential safety risk while driving. I am concerned this may be related to a defective fuel system.

NHTSA complaint #11709821 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE:DELIVERY:FUEL PUMP

Please see Attachment To Whom It May Concern, I am writing to formally notify you under the Virginia Motor Vehicle Warranty Enforcement Act (Virginia Lemon Law, Va. Code §§ 59.1-207.9 to 59.1-207.16) that my 2021 Hyundai Sonata, has a nonconformity that substantially impairs its use, value, or safety. On June XX, 2025 I delivered my vehicle to Pearson Hyundai for repair due to the fuel pump recall. As of today September XX, 2025 the vehicle has been out of service for more than 89 days, well beyond the 30-day threshold set by Virginia law. Despite this, the manufacturer has failed to complete the required recall repair in a reasonable amount of time. This constitutes a violation of my rights under Virginia’s Lemon Law. Therefore, I am formally demanding relief as provided by law: Repurchase of my vehicle for the full contract price, including taxes, fees, and incidental charges, less a reasonable allowance for use, OR Replacement with a comparable new vehicle acceptable to me. Please respond in writing within 15 days of receipt of this letter. If this matter is not resolved, I will be forced to escalate through the Virginia Attorney General’s Office, the National Highway Traffic Safety Administration (NHTSA), and, if necessary, legal action.

NHTSA complaint #11709594 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

Recall number (25V796000) There is No remedy available. I am Experiencing fuel system issues that may relate. Dealer and corporate refusing meaningful support and expecting me to pay $1,600 to replace fuel assembly. I feel unsafe driving my vehicle at this time.

NHTSA complaint #11707812 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

I own a 2021 Hyundai Sonata 1.6T, which has an open NHTSA safety recall (25V796000) related to fuel tank pressurization and fire risk. I brought the vehicle to an authorized Hyundai dealership due to a check engine light, reduced performance, and DTC P14EE, which aligns with the recall condition. The dealership refused to treat the concern as recall-related unless I paid a diagnostic fee and later attempted to reclassify the issue as a customer-pay fuel pump repair. During this visit, the dealership replaced a fuel system sensor without my authorization, which I did not approve or consent to. The dealership has not provided documented test results explaining how the recall condition was ruled out and has not documented recall inspection on the repair order. I expressed that I do not feel safe driving the vehicle due to the fuel system recall and drivability issues. The dealership also refused to provide alternate transportation. I am concerned the recall is not being handled in compliance with NHTSA requirements and that unauthorized repairs were performed while attempting to shift a recall-related condition to the customer. I am requesting review of recall handling and dealer compliance.

NHTSA complaint #11707864 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

The car would excelerate while in park. While I was pressing the brakes the car would jerk forward, it would not just quietly idle. While driving the car would randomly speed up or slow down. Sometime it would sound like it was going to shut off and start vibrating.

NHTSA complaint #11656443 — an unverified report by a vehicle owner.

FUEL SYSTEM, GASOLINE:FUEL INJECTION SYSTEM:INJECTORS

The contact owns a 2021 Hyundai Sonata. The contact stated while pulling out of a parking lot, the vehicle failed to accelerate as intended and started shaking abnormally. The check engine warning light was illuminated. The vehicle was taken to the residence. The vehicle was towed to an independent mechanic where it was diagnosed that the fuel injector needed to be replaced. The vehicle was towed to a dealer where it was diagnosed that all four fuel injectors needed to be replaced. The vehicle was repaired. The manufacturer was not notified of the failure. The failure mileage was 47,000.

NHTSA complaint #11645969 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

I have been to the dealership on three separate occasions due to the engine misfiring. Two ignition coils have been replaced so far and I recently returned to the dealership for the same issue. This time however, not only did the engine light come on but I went from a full tank to less than a quarter of a tank and the engine is making backfiring sounds. At that time the dealership said that they could not recreate the issue, I got my oil changed and went home. That was a week ago, I am back at the dealership today for the same thing; fuel dumping and backfiring sounds. While at the dealership today it turns out those backfiring noises were the fuel tank expanding so much so that it kept popping the seat up. They deemed the car unsafe to drive and it is currently at the dealership.

NHTSA complaint #11603481 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

When attempting to pass other vehicles or under quick acceleration such as an on ramp to the highway, the vehicle will experience a sudden loss of power and oil pressure resulting in a fail safe mode which limits your acceleration and causes a sudden decrease in speed and velocity. The issue results in the oil pressure light illuminating and requires the vehicle to be stopped and completely turned off to reset then once turned back on, the problem is “gone” until a sudden acceleration occurs again, which results in the same issue happening. There is a current recall out for similar models but my vin is not listed. I have approximately 50k miles on the car, and am the first owner.

NHTSA complaint #11525992 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

My car barely has 11,000 miles and just the other day it had about 20miles left of gas but as I was driving on the road it started to feel and seem like it was about to die on me, Also the front Wipers are not well restrained with the vehicle you can tell by the way it moves when Wipers are on....Also most of the Signals be It if something is in front of me and the signal goes off BUT THERES NOTHING THERE ...ALSO WHEN IM BACKING UP SOMETIMES the car itself will Force stop as if something is in the way ...BUT AGAIN NOTHING IS THERE AT ALL ...IT HAPPENS EVERY FEW DAYS ....I JUST PURCHASED THIS CAR ..AND REALLY THINKING IT WAS WORST MISTAKE W ALL THESE ISSUES ALREADY

NHTSA complaint #11509258 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

Oct 12: Engine stalled exiting I95 in Kittery Maine. Engine light flashed but did not stay on. Was able to get to safe place but car would not go more than 15mph. Hampton Huyndai reported mis-fire but stated it cleared on its own. Oct 17th: Engine stalled on highway ramp to I495, nearly causing me to be rear ended by other vehicles. Car would not go more than 15 mph. Engine light stayed on. Towed car to Key Salem Hyundai, defective injectors, warrantee repair. Oct 23rd: Car stalls on I93, was able to take immediate exit and turn engine off. Engine light flashed but did not stay on. Took car in to Salem dealership on Oct 24th, no code found. Oct 25th: Car stalls again on city street. Light stays on, Salem dealership replaces cat. convrtr between Oct 26th through Nov 4th. Nov 9th: Car stalls again on city street. Light stays on, currently in Salem dealership. This is a safety issue, in two cases already this car has nearly gotten me in an accident on the highway. I am seeking arbitration for replacement. I am scared to drive this vehicle. I will have a third invoice pending this next repair.

NHTSA complaint #11492999 — an unverified report by a vehicle owner.

FUEL/PROPULSION SYSTEM

UNKNOWN

NHTSA complaint #11488472 — an unverified report by a vehicle owner.