2018 Hyundai Sonata Transmission Problems

Your engine has developed a serious internal problem that started with loud knocking when cold-starting and has progressively worsened. By early 2026, oil began visibly leaking from your exhaust pipe while the engine runs, indicating internal engine damage like worn piston rings or failed valve seals. This creates safety risks including potential loss of engine power while driving, engine seizure, and a fire hazard from oil in the hot exhaust system. Fixing this will likely require internal engine repair or replacement, which is a major job.

Your 2018 Sonata experienced multiple warning lights, abnormal engine noises, and repeated mechanical failures shortly after purchase despite low mileage. You noticed instability while driving and loss of power that made the vehicle unsafe to operate. These problems persisted even after repairs and maintenance, and ultimately contributed to a highway accident. Diagnosis and repair will likely require a full powertrain and electrical system inspection to identify the source of the warning lights and mechanical faults.

Unknown what system failed. The vehicle is at an impound lot and can be inspected on request. Police and fire department were on the scene.

My 2018 Hyundai Sonata (approx. 60,000 miles) began consuming excessive oil, and the engine started smoking while driving. My wife barely made it to the dealership — the car was unsafe, struggled to stay running, and visibly smoked from under the hood.

My car is part of a campaign due to rod-bearing failure where the engine experiences problems such as complete failure, vibrating, hesitating, engine light on, and oil light on. I've been communicating with Hyundai who is not helping me with this issue. I was advised by them to continue driving the car "until the engine seizes", or I hear "a loud knocking noise".

My car is misfiring, hesitating accelerating, severely shaking and vibrating which you can feel in the pedals and steering wheel, and the check engine light is on. This issue has been ongoing for over a week already. When the engine light first came on on 9/7, I pulled over on the side of the road and had a mobile mechanic check it out.

The contact owns a 2018 Hyundai Sonata. The contact stated that while driving approximately 60 MPH the vehicle suddenly began sputtering and then completely stalled. The contact had to coast to the side of the road and noticed the check engine light illuminated.

Your 2018 Sonata has broken down repeatedly every few months, requiring coil pack and spark plug replacements costing $300–$600 each time. You're also losing oil between oil changes and need to add about $20 of oil weekly. The repairs may involve replacing failing ignition coils, spark plugs, and investigating the engine for oil leaks or internal defects.

While driving on the highway, my 2018 Hyundai Sonata experienced sudden loss of engine power and became undrivable. The failure occurred without warning at approximately 86,500 miles. At the time of the incident, there were two children in the vehicle, and the breakdown occurred at night in cold temperatures (approximately 20°F).

The car in recent months has twice lost power and been rendered in operable on the side of the road until it could be limped home. I had the car serviced last year for a recall of a fuel filter gasket and at that time I was informed that I also had an update done for a (k knock?) sensor prior done on the car before purchase.

On [XXX] I was driving on [XXX] [XXX] from Rockville, Maryland when my vehicle (2018 Hyundai Sonata Limited) started to lose power and control and all dash lights started to show. I was able to move the vehicle to the highway shoulder before all power and control failed.

The contact owns a 2018 Hyundai Sonata. The contact stated while driving 70 MPH, the vehicle went into LIMP Mode and lost motive power. The contact was able to pull to the side of the roadway, where the vehicle failed to restart.

The contact owns a 2018 Hyundai Sonata. The contact stated while driving 70 MPH, he heard an abnormal noise, and the vehicle began to vibrate. The contact stated no warning light was illuminated.

My 2018 Hyundai Sonata GDI Engine stop working while I was driving on the freeway without a warning prior to the issue. It never gave me a heads up in advance that the engine needed service. No check engine light to alert me that an issue needed attention.

I was stopped at a red light and when it turned green, I began to accelerate. The car stuttered and the check engine light was blinking. I pulled over and had Autozone run the code.

Engine failure. Definitely a safety issue, check engine light flashing, limited engine power. Wouldn’t accelerate.

The engine shuts off, doesn’t start, check engine light flashing, losses power, jerks while driving it, I will get it up yo speed then will shut off or won’t move.

Severe oil leak into the oil pan has required frequent maintenance to keep oil in the car.

Starter replaced at less than 50,000 miles. Normally a starter will last 150,000 miles or more. I was past the warranty by 9 months but was under the mileage.

I have had a new engine put in my Sonata back at the beginning of 2023. For the past two days my car will jerk really hard, and then loose power not accelerating over 25 rpms and my check engine lights comes on when it jerks really hard.

When accelerating from a stopped position the vehicle shudders or stutters before proper acceleration is achieved. I owned a ford fiesta that did the same thing and it turned out to be the clutch. Is that a possibility with my sonata?

In feb 2020 my sonata went into safe mode after exiting highway and dealer ended up replacing "knock sensor". In december 2020 my engine "stuttered" throwing me forward as if I had hit brakes hard. No warning lights or messages occurred and after a few seconds car acted normally mostly.

I get a hev warning telling me to shutdown my car. When this happens my vehival no longer engages the gas part of my motor, the car gives me multiple distracting noises. After turning the car off and back on immediately the gasoline side of my motor is working again..

I was driving my car at about 45mph on my way to work on a highway road and out of no where it jerked and the check engine light started flashing. Car would not accelerate above 2,000 rpms. When the car jerked, it was so sudden it injured my lower back.

I WENT INTO PURCHASING DEALER FOR FIRST OIL CHANGE AT 5100 MILES, THEY FLASHED COMPUTER AND LOADED UPDATE HYUNDAI CAMPAIGN 953 PRODUCT IMPROVEMENT. ABOUT 50 MILES AFTER THE RECALL WAS PERFORMED MY CAR WENT INTO LIMP MODE AND IS BARELY DRIVEABLE. CAR WAS ALSO HESITATING, AND BUCKING A BIT. TOOK IT BACK TO DEALER THEY STATED THE CODE DIDN'T APPLY TO MY CAR AND FLASHED IT AGAIN. IT AGAIN WENT INTO LIMP MODE AFTER 50 MILES OR SO. THE RECALL IS SUPPOSED TO PLACE THE VEHICLE IN LIMP MODE DUE TO ROD BEARING WEAR. MY CAR HAS 5,400 MILES ON IT AND IT NOW AT A DIFFERENT DEALER. GOT INFORMATION FROM THAT DEALER REGARDING A TBS #19-01-002 AND LOOKS LIKE ENGINE REPLACEMENT OR WIRING HARNESS.

Throttle response: feels like the old vehicles with a flat spot in the carburetor accelerator pump. The "three second' rule applies when the throttle petal is pushed. There is a serious hesitation as the engine tends to fall flat before accelerating.

The car went into limp mode they have problems with the knock sensor and that is what it threw to the computer and I changed the sensor and went away and now limp mode again and computer says basically the same thing there is a software update and the engines are failing

I was going 80 MPH on the interstate and suddenly my car went into limp mode and shooked really hard and dropped to 60 MPH. I had to swerve to go onto the side of the road. The car behind me almost rammed into me.

When my car suddenly stopped on the highway, I encountered an issue with the “body control module.” The car wouldn’t start, and the key fob was ineffective. Additionally, the airbags stopped working. I don’t recall all the details, but I was unsure of where to report the dangerous vehicle.

transmition problem , stop and go high rev engine sutck in geer angine stals in stop and go tslow moving trafic

I had a recall performed on my car. 'hyundai campaign 953 product improvement '. 10 miles after the recall was performed my car went into limp mode and is barely driveable.

Purchased new 2018 sonata sel model in california. While driving, the transmission starts to hard downshift when the brake is applied. I found out that this hard downshifting and jolting/thumping of engine and transmission only occurs when coming to a stop at speeds between 10 to 15mph.