Hyundai Sonata Hybrid loss of power problems

Filed Sep 18, 2026 · Fuel system, Transmission · VA

​My Lincoln Nautilus (~9,180 miles) logged 6 "Powertrain Malfunction / Reduced Power" alerts in the [XXX] telematics system between XXX (XXX at 7:59 PM and 8:16 PM; XXX at 1:07 PM and 1:39 PM; XXX at 11:16 PM; and XXX at 10:56 AM). Out of the 6 logged events, I experienced severe loss of motive power during two of them. On XXX, while driving 70 mph on I-95, the vehicle completely lost all propulsion. Coasting without power, I was unable to pull fully onto the shoulder, leaving the car partially stuck in active traffic and narrowly escaping a high-speed collision. Once stopped, the vehicle failed to recognize that it was in Park, causing the electronic parking brake to lock without releasing, which severely delayed towing recovery. The vehicle was towed to a Lincoln dealership in [XXX], whose service department was closed. Upon arrival, the vehicle suffered a complete electrical blackout; the key fob would not unlock the doors, requiring physical key entry. A sales representative provided a jump box, allowing me to start the car, drive back to [XXX], and deliver it to Cavalier Lincoln Ford in [XXX] between 5:00 PM and 7:00 PM on XXX. Cavalier Lincoln Ford stated they could not reproduce the malfunction. The vehicle and its electronic records remain available for inspection upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 5, 2026 · Electrical, Engine · MI

The vehicle experiences sudden, complete electrical power loss while driving at speed on highways and city streets or on the parking. All digital displays turn off, the engine shuts down, and power-assisted steering and braking are instantly lost without prior warning, presenting an extreme collision risk. The issue first occurred in August 2025 at approximately 48,000 miles and was taken to an authorized Hyundai dealer in Michigan for warranty repair. The dealer held the vehicle for over 30 days but failed to correct the defect. The identical power failure has continued and recently escalated to daily occurrences. A second Hyundai dealer (Pacifico Hyundai, Philadelphia, PA) diagnosed an intermittent open circuit in the engine wiring harness but Hyundai Motor America refuses to repair the vehicle under warranty, claiming 'outside influence' without providing evidence. Driving a hybrid vehicle that randomly cuts all power in live traffic is a life-threatening safety hazard. Hyundai Motor America has failed to rectify this critical safety defect.

Filed Jun 10, 2026 · Engine · GA

The Hybrid Electric Vehicle (HEV) system in my 2017 Hyundai Sonata Hybrid Limited malfunctioned. On three separate occasions, the HEV warning light illuminated while I was driving on the highway, followed by a sudden loss of power. The vehicle stalled and stopped running, leaving it inoperable. The incidents occurred in approximately August 2022, November 2023, and February 2026. The vehicle is available for inspection upon request. Each incident occurred while driving on a highway. The vehicle suddenly lost power and stalled in moving traffic, creating a significant safety hazard. I was forced to attempt to move the vehicle out of active traffic lanes while other vehicles were traveling at highway speeds. The unexpected loss of propulsion increased the risk of a crash, serious injury, or death to myself, my passengers, and other motorists. The vehicle was taken to a Hyundai dealership after each incident. However, the dealership did not provide an explanation for the HEV warning light, loss of power, or stalling condition. To my knowledge, no permanent repair was identified, and the problem recurred on multiple occasions. The vehicle was inspected by a Hyundai dealership following each towing event. The vehicle was towed after each incident because it was not safe to drive. To my knowledge, Hyundai did not provide a definitive cause for the failures. The vehicle has not been inspected by police or insurance representatives in connection with

Filed Oct 9, 2025 · Electrical, Engine · FL

The car will randomly lose acceleration and jerk forward. It will make a beeping noise while the hev system warning flashes on the dash. It also says to turn off engine. While the warning is flashing and engine light is on it goes into a limp mode and you have limited acceleration. It has almost caused multiple wrecks when I go to acceleration from turning or at lights in traffic because I cant go over 20-30 mph. I have turned the car on and off and the hev system and engine light turns off and the car continues to work normal. It eventually comes back on and does the same loss of power/hev warning. It will be random and does not matter on how fast you are going to trigger the warning lights and loss of power.

Filed Jul 3, 2025 · Fuel system · VA

Car is a Sonata Hybrid Limited equipped with a solar roof which charges the hybrid battery. Vehicle began to cut off battery power while parked, requiring the use of a factory equipped 12V override switch in March 2025 after approximately 3.5 years of ownership. This occurred multiple times, often when the car was parked in the sun but independent of how long it had been driven prior or how long it had sat without being started. Evaluated by two Hyundai dealers; second dealer found a fault in the "solar DCDC converter" as well as the hybrid battery bulging. Battery module replaced. Unclear if this resolves the issue or it will recur again. Am speaking to Hyundai regarding battery warranty extension as vehicle had 88000 miles on it at the time of the issue starting. Online fora (e.g., Reddit, Facebook) note other customers who have had similar problems with similar fixes. - [XXX] - [XXX] - [XXX] - one individual in this thread had complete power loss while driving down the highway This issue potentially risks stranding customers, and if the hybrid battery continues to bulge increases the risk of fire which could lead to property damage, personal injury, or death. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jan 18, 2025 · Engine · MA

I bought this car brand new in november 2023, by february, the car started stalling on the streets/hyway. All dash lights would come on, the vehicle would stall and is no longer able to restart. This happened 4 time in 2024. When I tow it to the dealer, they always come back with the same answer. ''the AC motor power cable has been disconnecting leading to lose of power''. They have replaced it 4x but the same problem persist. It's very scary especially whn am driving in a busy road or when am driving at night in the middle of winter. Am not sure how to move from here. Thanks.

Filed Oct 18, 2024 · Electrical · UT

The car has completely lost power. Can not enter. Have to use the mechanical/physical key on the fob. Its been happeneing 7-8 times in the last year. It has a battery reset button we reset it from the dash which has a dedicated button just for this?

Filed Sep 2, 2024 · Electrical, Engine · NY

While driving, car started to lose power. Warning lights started flashing to turn off vehicle to recharge battery. Car lost all power. Car was towed to dealership. Dealer started diagnostic testing, and first thing that was noted is that all oil had drained from car and that crank shaft may now be damaged. Prior to incident, no warning lights came on for service, engine or oil lamp. Dealer and internet searched confirm this has been happening to this model recently.

Filed Aug 31, 2024 · Engine · TN

This is the seventh occurrence of complete loss of power while driving on the interstate. The hybrid system warning activated, followed by the engine shutting down, and all dashboard lights illuminated with alerts indicating "Shut Off Engine/HEV." An 18 wheeler was pulling out from the shoulder as I was losing power and barely missed getting crushed. The former problems have all been at interstate speeds with similar accident avoided. The service history clearly demonstrates that Hyundai has repeatedly attempted to address this issue by replacing numerous critical components, including the engine, transmission, knock sensor, battery (three times), integrated brake actuation system, and smart cruise control, among others. Despite these extensive repairs, the problem persists. On this latest occasion, less than 4,000 miles and four months since the last major incident, the dealership has proposed replacing the intake manifold, EGR valve, HSG belt, and spark plugs. The belt was changed less than 20K miles ago. and I believe the spark plugs were as well. Each time my vehicle experiences this issue, it is out of commission for weeks or even months at a time, causing significant inconvenience and raising serious safety concerns. I no longer trust this vehicle and I don't believe the many recalls have successfully addressed the root cause of issues with the 2017 Hybrids.

Filed Jun 3, 2024 · Steering · NY

Total loss of power steering while driving, wheel locks up randomly. Hyundai dealer said the battery was old, I put a new hyundai battery in it and the steering locked up leaving the dealership. VERY DANGEROUS.