general problems of the 2020 Hyundai Sonata

Vehicle experienced intermittent, severe powertrain defect resulting in a critical safety hazard. Between 30k and 36k miles, the vehicle underwent 3 violent highway deceleration episodes. During these events, the engine began shaking, escalating to violent shaking; with deceleration and coming to a stop, it would shake, then sputter as if it would die. Coming to a complete stop, a total stall was prevented only by the ecm forcing a limp mode lock at 1200 rpms. When auto hold was engaged at this point and my foot was removed from the brake pedal, the mechanical surge caused the vehicle to unexpectedly lurch forward, fighting against and nearly overriding the factory auto hold braking safety feature before finally holding. Luckily, no pedestrian was walking in front of my car when this occurred. No check engine light (cel) or dashboard warning ever illuminated. This safety compromise is directly tied to an ineffective or adjacent remedy involving service campaign 9b1 (opcode 40d219r0) and safety recall 286. Under this opcode, a factory software flash deleted the standard obd-ii trouble code p0451and substituted it with a manufacturer-specific shadow code p14ee00. This software manipulation suppressed universal emission/pressure sensor faults, masking a volatile physical defect within the high pressure fuel delivery and ignition systems. Dealer diagnostics on a running, compromised engine flagged an improper fuel injector pulse and subsequently a failing cylinder 3 ignition coil. All four injectors were replaced but only one coil, leaving 3 non-updated , factory defective coils in the engine. The vehicle remains an ongoing highway stalling and brake-override hazard due to an incomplete field remedy of a recall-adjacent system. I've filed a Hyundai complaint with assigned case number 43394228 regarding safety recall 286. (two episodes of the attempted auto hold override occurred - first 09/09/2026 and second 09/29/2026. ).

Parking malfunction. Parked, running car moved itself to reverse and backed up a driveway crossing a dirt road and hitting a fence and post. This car could have hit and severely injured anyone who was in the path while it was reversing on its own. Car was in reverse and all parking sensors were blaring when the car was found minutes later.

Fuel system recall (NHTSA 25v796; Hyundai 286/23hyz2 "fuel tank expansion") on a 2020 Hyundai Sonata, plus the fuel-tank heat shield and rear floor pan area. On 4/21/2026 (110,423 mi. ) a Hyundai dealer's recall test failed; no warning lamps or symptoms beforehand. The repair order says Hyundai "is declining the repair at this time and is calling the customer to offer assistance. " Hyundai's advisory: "do not drive, park outside. " Hyundai's recall filing says heat shield/exhaust contact "could contribute to fuel tank damage" (a fuel-leak/fire risk, I understand). The dealer also noted structural damage at the rear. On 8/1/2026 Hyundai consumer affairs confirmed in writing the repair was denied "to provide consumer affairs time to contact you to discuss a possible repurchase" ("standard practice"): about 102 days for a business reason, not a technical one. I elected repair 8/4. Every completion date since passed (8/26 "2-3 weeks"; 9/7 "end of this month"; 9/18 "end of next week"). On 10/5 Hyundai emailed that the car "has since been picked up. . . Post repairs"; it had not (the dealer says its manager told Hyundai the work was done "at the body shop"). On 10/6 the dealer said the repair is complete but unverified, the repair order is "partially closed," and the car was jumped and driven in; the body-shop work is a roughly $15,000 warranty repair with no paperwork. Sitting damaged the car: rusted brake rotors and a failed battery that was recorded "ok" at intake; the dealer first asked me to pay for a new one, then reported Hyundai's approval on 10/6. 168 days; the remedy is not verified complete, and no pickup date or advance notice has been agreed. Not asking NHTSA to resolve a financial dispute. Vehicle and removed parts may be available for inspection per dealership. Documents (repair order, Hyundai's written correspondence) are available on request.

I own a 2020 Hyundai Sonata. I purchased the car on January this year the miles in the car is 700 miles. A month after the car star giving me problem with break. Somehow the car applies the emergency break by itself and doesn't want to move. When I drive the car suddenly stop by itself and giving me message like: to move the car put your seat belt, lock all the door even when I have my seatbelt and doors are lock the car do that when ever the less I expected. I took the car three time for repair and update and the car give me the same problem. The dealer gave me a loaner another 2020 Sonata and have the same problem. This is a very dangerous issues because if is rainy or snowing. The dealer doesn't find anything wrong with the car when they drive the car. I told them that happen when the lees expected.

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.