2023 Hyundai Sonata: sudden loss of power

Filed Sep 23, 2026 · Brakes, Driver assistance · NY

While driving at highway speeds, the emergency brake system will apply and alert me. It’s happened twice now in the last 3 weeks. I’ve experienced a random loss of power while driving on the highway with no check engine light on the dashboard. Lastly, at lower speeds the car will randomly jerk while accelerating with no lights on the dashboard as well. I’ve gone to the dealership but they wanted to charge me a diagnostics fee to first look over the vehicle, which I don’t feel I should be on the hook for since the issue isn’t user caused.

Filed Aug 7, 2026 · Engine, Fuel system · VA

I own a 2023 Hyundai Sonata SEL. Over approximately three years, the vehicle experienced four separate incidents involving sudden loss of engine power and recurring fuel injector/powertrain problems. Three of these incidents occurred while the vehicle was being driven on interstate highways, creating serious safety concerns. The first incident occurred on XXX, on [XXX] [XXX]. My daughter was driving the vehicle at the time when it suddenly lost power while traveling on the interstate. She had to maneuver the vehicle to the shoulder under unsafe traffic conditions. The second incident occurred on XXX, on [XXX] near [XXX]. I was driving the vehicle when it again experienced sudden loss of power while traveling at highway speed. The third incident occurred on XXX, in [XXX]. The vehicle experienced another significant power-loss event and required roadside assistance. The fourth incident occurred on XXX, on [XXX]. The vehicle again experienced a sudden loss of engine power while I was driving on the highway. Despite multiple repair attempts, including repairs related to the fuel injectors, the same or substantially similar power-loss problem continued to recur. Because the vehicle has repeatedly lost engine power while being driven, including multiple incidents at interstate highway speeds, I believe this recurring condition presents a serious safety risk. I am reporting these incidents so the federal safety agency can evaluate whether this may represent a broader safety-related defect affecting this vehicle model. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed May 14, 2026 · Engine, Transmission · TX

This is an extremely common issue plaguing Hyundai & Kia vehicles with the Theta III 2.5L Turbo engine, Such as Kia K5 GT, Hyundai Sante Fe, Hyundai Santa Cruz, & Hyundai Sonata N-Line. Its a failing ITM (integrated thermal management) unit or otherwise known as an ITMS unit. There is a rod within the ITM that prevents proper control of the flow of cooling the oil and engine coolant of the engine. Results in Cooling issues, such as a cold lower radiator hose while the engine is hot, or 'limp mode' during acceleration, that causes a sudden loss of power while trying to merge on the expressway. There has been other Kia models and years that have had TSB's related to fixing this issue, but Hyundai has released nothing. I have uploaded an example of one of the TSB's that do not apply to my car. Technical symptoms often include: Fans running 100% full duty (high) while the lower radiator hose stays cool. Or Fuel dilution or a 'rich' running engine. Because the engine is overcooling that keeps the car's fueling rich and in a open loop mode affecting emissions and contaminating oil. Personal Details of exactly what happened when i noticed mine was failing. I ran home on my lunch break, and while accelerating on a ramp to get up on a highway, my car started beeping and flashing "Engine Overheated" and i immediately let off the gas with preparation to pull over. The second i left off the gas, the coolant temp within 1-2 seconds went from a little over 3/4 the way up the gauge back to normal a little below half temp. I resumed driving a 3 mile drive back to work, with it showing normal temps the rest of the way. I popped the hood when i got to work to see if coolant was low, and it was completely normal, a little over halfway between the min/max lines. The car continues to run hot, often with the cooling fans running at 100%.

Filed Mar 16, 2026 · Electrical, Engine · FL

Battery Management System completely exhausting the 12V battery resulting in the car acting as if it has no power. When this happens, you can't unlock the door or open the trunk. On two separate occasions, I have encountered a complete loss of power in my Sonata Hybrid, preventing me from unlocking the trunk or doors upon returning from extended trips. The first incident occurred after a ten-day absence last Fall, and the most recent was on Saturday, March 14, 2025. During the latest incident, I returned from a seven-day trip and found my vehicle parked at Orlando International Airport. Upon approaching the car, I anticipated being able to unlock the trunk, load my luggage, enter the vehicle, and drive home. However, once again, the vehicle was unresponsive. Accessing the car required removing the cap from the door handle and manually inserting the key, a process that took approximately ten minutes, which was particularly inconvenient and concerning in an airport parking lot. This situation was even more challenging considering I am a [XXX] woman of smaller stature attempting to resolve this issue alone at night. I believe this poses a serious safety concern for all owners under similar circumstances. Following the incident last Fall, I brought my Sonata Hybrid to Key Hyundai in Jacksonville. I was informed that this is a known issue for which there is a recall; however, my vehicle model year is not included in the affected range. It was suggested that I would need to manage this problem independently. I believe this recurring issue represents a known vulnerability that could potentially expose Hyundai and its dealerships to liability should an owner suffer harm while addressing this malfunction. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jan 7, 2026 · Transmission · GA

On January 6, 2026, during my morning commute in heavy traffic, my 2023 Hyundai Sonata engine unexpectedly turned off, causing a sudden loss of power. This created an extremely dangerous situation, and I came very close to being involved in a major collision. While I was fortunate to avoid a crash, the incident posed a direct threat to my safety and life because of the dense surrounding traffic.

Filed Jan 2, 2026 · Fuel system · GA

Hello Sir/Madam, While driving on Interstate I-75 at approximately 70 mph, the yellow check engine warning light suddenly illuminated. Immediately afterward, the vehicle began to shake violently, lose engine power, and run extremely rough. The vehicle experienced a sudden loss of power, and pressing the accelerator pedal did not result in normal response or acceleration. The throttle input was significantly reduced, making it difficult to maintain speed and safely control the vehicle. At highway speed and in heavy highway traffic, if we had not been able to safely exit the roadway, this loss of control could have put not only the occupants of this vehicle but also other drivers at serious risk. Fortunately, we were already in the exit lane, and a McDonald’s parking lot was located immediately off the exit. This allowed us to leave the highway quickly. Otherwise, this situation could have been extremely dangerous in active, heavy highway traffic. As the vehicle continued to shake, a strong smell of gasoline and a burning odor entered the cabin, raising concerns about a possible fire hazard. We safely stopped the vehicle in the McDonald’s parking lot and then shut the engine off due to the severity of the symptoms. After shutting the vehicle off, we attempted to restart it, but the engine would not start. The vehicle had to be towed to a Hyundai service center for inspection. The Hyundai service center later confirmed that the failure was caused by a faulty fuel injector, and they have changed all 4 injectors as I attached receipt from Hyundai This failure created a serious safety risk due to sudden loss of engine power, reduced accelerator response, severe shaking at highway speed, and fuel and burning odors inside the cabin. Regards

Filed Nov 7, 2025 · Fuel system · TX

Fuel injectors cause car to lose power while driving in traffic, on the highway which can cause accidents. This event happened twice one while entering the highway and one while going past a light. Neither caused an accident at the time. The car both times were taken to the dealership and the fuel injectors had to be replaced both times. The first time was in December 2024 at 12k miles

Filed Oct 17, 2025 · Fuel system · TN

While driving at highway speed, my vehicle suddenly lost power due to fuel injector failure and could not be restarted, creating a serious safety risk for myself and others in high-speed traffic. This is the second vehicle of the same year and model that I’ve owned to experience the exact same injector failure. In the first case, one injector was replaced under a Hyundai service bulletin before I sold the vehicle. This second occurrence confirms that the issue is not isolated and should be escalated to a formal safety recall. The most recent failure was diagnosed and repaired by Hyundai, confirming the problem (this time replacing all injectors). The vehicle has not been inspected by police, insurance, or other outside representatives. There were no warning lamps, messages, or symptoms prior to the failure—it occurred without any warning, significantly increasing the risk of a crash

Filed Jan 25, 2025 · Engine, Transmission · NC

2023 Sonata N-Line, complete loss of power while driving on seven (7) occasions over the past year. In all cases above 60mph creating a dangerous condition to myself and fellow drivers while attempting to pull to the side of the road while rapidly losing speed. In all seven (7) cases, the DTC code is P065312. I have asked the dealership to note the recurring issue in my service records and I have reached out to Hyundai, mostly so that if I am involved in a serious accident because of this issue, there is a paper trail for legal purposes. The dealership folks are nice but basically unless the car rolls into the dealership with smoke pouring out of the engine, they want to charge a diagnostics fee and keep the car for multiple days which isn't helpful because like most, I need the car and the issue is extremely sporadic. It is disappointing and I hope Hyundai takes note and provides remedy for the issue sooner rather than later as this is my sixth (6th) Hyundai vehicle and really do like the car otherwise. All incidents below: 01/23/2025 - 9531 miles 01/20/205 - 9128 miles 12/15/2024 - 5500 miles 12/13/2024 - 5374 miles 11/22/2024 - 2409 miles 01/12/2024 - 568 miles 01/08/2024 - 554 miles

Filed Dec 16, 2024 · Fuel system · MD

I bought the new car on 11/21/22. There have been two incidents with the same cause. Incident #1: On 1/25/23, while I was on a six lane highway with high speed traffic and rush hour level traffic, the car began to fail, with 'bucking', failure to respond to the gas pedal, loss of power, and difficulty steering. At that time, the check engine light also went on (it had not been on previous to the event starting). I was able to get the car off the highway, where it completely died - it would not move. It was towed. Mileage at this time was 1,330 miles - the car was 2 months old. It was diagnosed that "Cylinder #3 fuel injector is stuck open causing drivability issue". The likelihood that I would have been hit, by another car on that multi-lane highway with cars at high speed, and hurt or even killed is extremely high, if not certain. I did not file a report with the federal safety agency about the first incident (I was not aware of this service.) Incident #2: On 12/7/24, while I was again on a six lane highway, high speed traffic, night darkness, rain, and rush hour level traffic, the car began to fail in the exact same way as in 2023, 'bucking', failure to respond to gas pedal, slowing, difficulty steering, etc. I was able to get off the highway before it completely 'died'. It was undriveable and had to be towed. There was no warning light prior to the event occurring. Mileage at the time was 21,091. The probability, considering the rain, the dark, and the fact that I was on a 'super highway', that I could have been hit, hurt or even killed is extremely high. The diagnosis was 'TSB indicated #3 Fuel Injector be replaced." I do not have any of the old fuel injectors. In addition, I routinely - multiple times a week - have small children in this car. These events could have happened when I had a carful of small children with me. My routine schedule means there was also the high probability of others being hurt.

Filed Jul 19, 2024 · Electrical, Engine · AL

I was driving on the interstate at interstate speeds and the car started to lose power. I was able to steer the car to a safe location and call roadside assistance. It appears that the engine control system had a failure in one of the control modules. The problem was reproduced at the time that I dropped the car off with the service center. The history of the issues for the vehicle are available. My safety was put at risk because the car lost power at high speed and I was only able to limp to a safe location. No warning lights happened until the issue was already taking place. After being notified by my Hyundai app, I was able to discover that the vehicle had a history of having this code (I have only owned the car for 32 days)

Filed Jun 14, 2024 · Engine, Fuel system · TN

On two separate occasions, one at @9500 miles and the next at @19,000 miles the car engine started shaking and lost all power while driving. Unable to steer car. Both times towed to dealer and they say it needs new spark plugs and need to clean cylinders. They do not know root cause of problem and have not done any testing of the engine, no leak/compression testing. Dealer refuses to cover cost of repairs saying out of warranty but cannot give any assurances this won’t happen again. I’ve requested they contact Hyundai engineers to find out what’s causing this and, to date, they’ve done nothing. Vehicle is unsafe to drive and is still at dealership with no reason to underlying issue.