2020 HYUNDAI SONATA Engine Problems

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)

The contact owns a 2020 Hyundai Sonata. The contact stated that the vehicle hesitated while depressing the accelerator pedal, with the check engine warning light illuminated on the instrument panel. The vehicle was taken to several independent mechanics and dealers to be diagnosed; however, the cause of the failure was not determined. The contact stated that one mechanic replaced an unknown sensor, but the failure returned soon after the repair. The manufacturer was notified of the failure. The vehicle was not repaired. The failure mileage was approximately 101,000

Mileage: 101,000

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

Been having an issue with a check engine light and a popping noise in the from the front of the vehicle for about two years. Took it to the dealership more than 3 times over that span and every time they discovered it was caused by something different..during the July of 2024 while driving on the interstate a loud pop noise was made from the back and my children complain about the seat lifting…shortly after I went to get gas and a full tank was more gallons than usual 14 increased to 17g…. I once again took it to the dealer for the issue of the gas tank expansion and pop but found nothing. No more than a week later my car would hesitate to accelerate and progressively got worse. On 12/27/24 I took it to the dealer and they discovered my gas tank was expanded and was unsafe to drive leaving me without a vehicle.as of 1/04/2025 I still have no solution.

The contact owns a 2020 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, there was an abnormal gasoline odor inside the vehicle, after which the vehicle lost motive power. The contact pulled over to the shoulder of the roadway, moved the rear seat, and observed that the fuel pump was protruding upwards. The check engine warning light was illuminated. The vehicle was towed to the dealer, who diagnosed a failure with the purge valve, resulting in damages to the fuel pump and fuel tank. The vehicle was repaired, but the failure reoccurred. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 47,000.

Mileage: 47,000

The contact owns a 2020 Hyundai Sonata. The contact stated while driving at an undisclosed speed, there was an abnormal gasoline odor inside the vehicle. The contact then heard a loud pop and pulled over to the shoulder of the roadway. After a visual inspection, the contact observed gasoline leaking from the fuel tank filler neck, even though the access door and gas cap were both securely closed. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the canister purge valve, causing the fuel tank to swell, resulting in damages to the fuel pump. The vehicle was not repaired. The manufacturer was notified of the failure, and a case was opened. The failure mileage was 47,000.

Mileage: 47,000

I was driving on the interstate when I heard a click from the back of the car. The gas gauge started to move downward as if I was losing gasoline. It eventually stopped and started moving back up, past where it was when it started decreasing. A little bit later the check engine light came on and the car started driving very sluggishly. I took the car into the Hyundai dealer and they found that the backseat was clicked out of place and a sensor was unplugged. This issue has since occurred multiple times. The back seat will pop out of place, the gas gauge will move beyond the gas that is in the tank, and finally the check engine light will come on and reduce the performance of the vehicle. The gas tank appears to be swelling and pushing up against the back seat which is causing it to pop. I had my girlfriend drive the car while I sat in the backseat and I could actually feeling something moving underneath the backseat. I have since gotten in contact with other sonata owners who have had the same thing happen with their vehicles. In other cases the backseat has exploded and flown completely off of the gas tank. I am very nervous to drive my car and think Hyundai should recall these vehicles before someone gets hurt.

Vechile shut down completely on the highway, engine's been replaced twice, Catalytic converter, Turbo was replaced three times, Battery oxygen sensors, timing belt all have been replaced, Along with my wireless charger and Both heaterhouses and splash guard. I recently had my vehicle SERVICED Thirty five hundred miles after NEW engine install The dealership serviced my car didn't reset my service indicator 3 weeks later, my vehicle without warning said Engine overheated, so I pulled over immediately that display went off. My actual thermostat stayed under the center line in between cold and hot. I contacted the dealership and got my vehicle into BE inspected At that time, they said my coolant level was low and both heapeer. Hoses needed to be replaced and my engine needed to be flushed and refilled. I had those services completed. I picked up my car 5/24 it was OK on 5/25 My service indicator pop back on and at that time it was counting 58 days, so even after I brought it to the dealership's attention, they failed to reset it again. So I googled how to reset the service interval and did it myself. And about thirty minutes later, I was driving my car started shaking excessively And Woodin's accelerate, over 20 miles per hour in traffic. I had to put on my hazard lights and get me and my grandson to a safe place so that I could contact the dealership regarding this matter and they stated there was nothing they could do I had to wait until Tuesday I have put in a complaint with the Better Business Bureau, as well as consumer affairs. And also the county attorney's office for. Consumer fraud. This vehicle was misrepresented at the time of sale. It has countless safety issues. I need assistance

In May of 2023 my check engine light came on. Took the car to the dealer and the diagnosis was that the egr cooler was the culprit so they replaced it and everything was fine until 12/21/2023. I am driving on the highway and suddenly I hear a loud alarm and upon checking my instrument cluster I see a warning for engine overheating, the heat was on but suddenly the smell of something burning covered the entire cabin of the vehicle. I had to pull over to the side in the middle of a busy highway in freezing conditions and shut my engine down to avoid further damage. I believe the egr cooler has failed once again inly this time leading to a more terrifying experience. My car was towed to the dealership but I am worried for myself and others with similar vehicles I would not like anyone to experience what I did. I have seen multiple online forums with people complaining about the same situation. Mileage was around 57,900 miles when this occured. I bought the car with 30,000 miles as a certified preowned model. I kindly request for a recall for affected sonatas manufactured from the year 2020 to ensure our safety on the road. If it was not for warranty I would not be able to pay for the repairs

Engine leaks oil. I went to the dealer and they blamed the other Hyundai dealer saying they stripped out the drain bolt. After all the back and forth they told me they will replace the drain pan. I scheduled to have the car dropped off and wasn’t given a loaner. When I went to pick up the car they told me the ac bolt and bracket are broken and to come on Monday but the drain pan has been replaced. I went home and the car continued to leak oil and when I went back to the dealer and called them out they came up with every excuse in the books. Bolt is stripped, impact to pan, and so on. Long story short I went to fix the oil pan and they damaged the ac bolt so instead of telling me to come back to do everything they said they did the drain pan but the bolt would have to be done another day. I am waiting on a loaner car as I waisted a whole day without a car and the issue wasn’t fixed. I have a receipt showing the work was done but it never was. The dealer is dishonest and unprofessional. Not sure how they get away with this. They need to be held accountable.

While driving my cars a light starting blinking and my engine light came on and the car lost power This has happened on at least 3 occasions and I had to pull over upon starting the car after a few hours all returned to normal I reported this to dealer and they could not find a problem

2020 HYUNDAI SONATA. CONSUMER WRITES IN REGARD TO GRINDING NOISE WHILE DRIVING. THE CONSUMER STATED UPON INSPECTION BY TOYOTA, IT WAS DISCOVERED THAT THE UNDERSHIELD HAD COME LOOSE AND DRAGGING.

Steering parts being replaced many times, and the engine oil is low after I just got an oil change a week ago. Excessive engine oil usage with no idea where it is going.

I first begin having an issue with the idle speed. It would jump up to 1,500 RPM, which is twice the normal 750 RPM level It started almost from the very beginning when I purchased this car new in early 2020. I mentioned it at first oil change at dealer at 3,500 miles. I was told it was normal. In the beginning it would come and go. Sometimes not happening for weeks in-between episodes. Then it started to have the check engine light come on after it would happen and stay on. I took it back while light was still on and they kept the car for several days. Said it was the EPV valve and replaced it. Car operated fine for a few days then started up again. It also started to idle up and down from 1500 down to 500 in a rapid succession. I was able to get it to stop sometimes by turning engine off and them back on. Again I contacted dealership and took car back in. They gave me a loaner car and kept my car for over a month. This time they replaced the computer they told me. I did not have car for more than a week before it started doing it again. It has gradually gotten worse and happens more often now. It has also started to have the Forward Collision Avoidance warning come on in addition to check engine light as well. Just this week it actually just died on me while driving and forced me to pull to side of road. Turn off the engine and restart the engine. This happen 3 times in succession. Dealership does not seem to have any idea on what is going on and have been not very helpful. 3 week wait to get an appointment to bring in and no loaner cars available. This problem with the 2020 vehicle is very dangerous. It can idle up at anytime and car will lurch, requiring forceful brakeing . Car dying while driving and losing power as well.

Driving, car started making a weird sound followed by a warning light on dashboard with dinging sound to correlate... car became difficult to gas, vehicle motion was lagging where I just knew I had to pull over Bc this car was going to literally stop began to slowly (Bc that’s all car would allow) to proceed forward and I was forced to come to a haunt as I pulled onto side of highway. I then could no longer move it. Turned car off for minute then returned to try to start again, car would not accelerate at all nor turn on fully.. I was forced to wait hour to get a tow... took to shop, no problem such was found , car started & ran again ... this is 3 days later the car again continued the same exact pattern & I was unable to drive any further and forced to once again to get tow. This has to be something of bearings with engine, this car mode is not on list but IT certainly is an issue that I believe is related & should be rectified by Hyundai.

ON NOV. 17 WHILE DRIVING APP. 65 MPH ON THE HIGHWAY THE CAR SUDDENLY SHUT ITSELF OFF. ALL OF THE DASHBOARD LIGHTS LIT UP & THE CAR WOULD NOT RESTART. AFTER 10 MIN. OF TRYING TO RESTART THE CAR, THE CAR STARTED AGAIN, & ALL THE LIGHTS ON THE CAR DISAPPEARED. THE FOLLOWING DAY, WHILE WAITING IN THE TURNING LANE AT A RED LIGHT, THE CAR SPUTTERED & TURNED OFF. ALL THE LIGHTS ON THE DASHBOARD LIT UP & THE CAR WOULDN'T START I HAD THE CAR TOWED ON NOV 18 202 TO A HYUNDAI DEALERSHIP. THE DEALERSHIP REPORTED THAT THERE WAS AN INTERNAL SHORT WITH THE ABS MODULE & THE HYDRAULIC MODULE ASSEMBLY WAS REPLACED. ON, NOV 24, I WAS DRIVING THE CAR & THE CAR STALLED ALL THE WARNING LIGHTS WENT BACK ON. I HAD THE CAR TOWED THE DEALERSHIP WHERE IT STAYED UNTIL DECEMBER 11 THE DEALERSHIP STATED THAT THEY COULD NOT FIND ANYTHING WRONG WITH THE CAR. I PICKED UP THE CAR ON DEC 11 & THE CAR APPEARED TO BE WORKING NORMALLY. HOWEVER, ON DEC19, WHILE STOPPED AT A RED LIGHT, THE CAR BEGAN TO SHAKE BACK & FORTH AT IDLE & THE RPMS STARTED TO GO UP DESPITE MY FOOT BEING ON THE BRAKES. THE CAR BEHIND ME SAW WHAT WAS HAPPENING & HELPED ME PULL OVER TO THE SIDE OF THE ROAD. I HAD THE CAR TOWED TO THE DEALERSHIP YET AGAIN. THE DEALERSHIP STATED THAT THEY WERE ABLE TO DUPLICATE THE ISSUE ON DEC 23, 2020. HOWEVER, NO FIX WAS DONE TO THE CAR. THE DEALERSHIP CLAIMED THAT THE CAR WAS IN A 'RELEARN' PROCESS & IT WOULD NEED MORE TIME FOR THE CAR TO 'RELEARN' HOW TO DRIVE AGAIN. EVERYTHING SEEMED OKAY AFTER THE DEC 23 INCIDENT UNTIL FEB 8 2021 WHEN I TRIED TO STOP WHILE IN TRAFFIC & THE BRAKES WOULD NOT WORK AT ALL. I NARROWLY AVOIDED GETTING INTO A MAJOR ACCIDENT & ONCE AGAIN BROUGHT THE CAR TO THE DEALERSHIP. THE DEALERSHIP FOUND THAT THE MASTER CYLINDER ASSEMBLY WAS INTERNALLY DEFECTIVE & WAS NOT HOLDING PRESSURE AND AS A RESULT THE BRAKES WERE NOT WORKING. THE VEHICLE WAS RETURNED TO ME ON FEB 11 2021.

Mileage: 1,389

TL* THE CONTACT OWNS A 2020 HYUNDAI SONATA. THE CONTACT STATED WHILE DRIVING 35 MPH AND ENTERING THE HIGHWAY, THE VEHICLE WOULD NOT SHIFT INTO GEAR AND THE VEHICLE WAS SPUTTERING. THE CONTACT STATED THAT THE VEHICLE WOULD NOT EXCEED 45 MPH. THE CONTACT PULLED ONTO THE SHOULDER OF THE HIGHWAY AND SHUT-OFF THE VEHICLE. NO WARNING LIGHT WAS ILLUMINATED. THE CONTACTED RESTARTED THE VEHICLE HOWEVER, THE FAILURE PERSISTED. THE CONTACT PULLED OFF THE HIGHWAY AND HAD TO RESTART THE VEHICLE SEVERAL TIMES. THE VEHICLE WAS TAKEN TO THE LOCAL DEALER - WEBB HYUNDAI MERRILLVILLE (1000 81ST AVE MERRILLVILLE IN 46410, (219) 249-4961) WHERE THE DIAGNOSIS WAS NOT DETERMINED FOR THE ENGINE HOWEVER, THE CONTACT WAS INFORMED THAT THE HEATING SYSTEM WAS FAULTY AND THE INSTRUMENT PANEL FAILED TO PROVIDE AN ACCURATE WARNING LIGHT FOR THE FAILURES. THE VEHICLE HAD NOT BEEN REPAIRED. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE BUT, DID NOT PROVIDE ANY FURTHER ASSISTANCE. THE FAILURE MILEAGE WAS 14,698.

Mileage: 14,698

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.

Mileage: 1,200

VEHICLE ABRUPTLY STOPPED IN A TRAFFIC SIGNAL WITHOUT GIVING ANY INDICATIONS WHAT SO EVER. WHEN TRIED TO RESTART IT STALLED PRETTY BADLY CAUSING EXCESSIVE VIBRATIONS. THIS HAD JUST 1900 MILES ON IT. VEHICLE DIDN'T HAVE ANY MIL OR ANY VISIBLE INFORMATION ABOUT THE ISSUE. IT CREATED A HUGE TRAFFIC PILE UP DUE TO THE PEAK HOUR IN WHICH THIS PROBLEM STARTED. FEW DAYS AGO THERE WAS ISSUE WITH STARTING BUT IT RESOLVED AFTER COUPLE OF MINUTES, THIS TIME THE VEHICLE HAD TO BE TOWED TO THE DEALERSHIP AND I LOST MY DAYS WORK AND PAY. BIGGEST CONCERN IS HOW ABRUPTLY IT STOPPED IN A BUSY STREET.

Mileage: 1

VEHICLE ROUGH IDLED & EVENTUALLY SHUDDERED TO A STOP. THIS HAPPENED FOUR TIMES WHILE IN GEAR AND IDLING AT APPX 1000-1500 MILES. BETWEEN 1500-2000 MILES, VEHICLE SHUT DOWN WHILE DRIVING APPX 60MPH ON A COUNTY ROAD. AT APPX 2700 MILES, MPGS DRASTICALLY IMPACTED WHEN VEHICLE SUDDENLY STOPPED SHIFTING GEARS PROPERLY WHILE IN MOTION AT APPX 70MPH ON THE HIGHWAY. CHECK ENGINE LIGHT APPEARED WITH MESSAGE REGARDING ECS ISSUES. VEHICLE STILL DRIVES, IT JUST SEEMS TO STRUGGLE WITH EFFICIENCY AND SHIFTING CORRECTLY.

Mileage: 2,700