2017 Hyundai Sonata Plug-in Hybrid problems

“I am reporting a serious safety issue involving a 2017 Hyundai Sonata Plug-in Hybrid (VIN: [XXX] ), originally purchased in California. While driving at approximately 70 mph on a highway, the vehicle suddenly lost all propulsion without warning and rapidly decelerated. This created a dangerous situation with surrounding traffic and put me and my family at risk. I had to quickly maneuver to the shoulder to avoid a potential collision. The vehicle was towed to an authorized Hyundai dealership in Utah, where it was diagnosed with a failure of the high-voltage battery system. I was informed that the battery requires replacement. This type of sudden loss of propulsion at highway speed is extremely hazardous and could result in a crash, injury, or fatality. There were no prior warnings indicating an imminent failure of this severity. Given the safety risk associated with unexpected loss of propulsion, I am concerned this may represent a broader issue affecting similar vehicles. The vehicle is equipped with an interior camera, and video of the incident can be provided if needed. I respectfully request that this issue be investigated as a potential safety defect.”

“On 12/20/25, the car - a Sonata plug-in hybrid - failed to start. When I pushed the "start" button, the dashboard display lit up w many clearly irrelevant error messages. Each time I pressed start, somewhat fewer error messages blasted toward me, and finally, no response at all. On 12/21/2026, the tow driver said it was the 12-volt battery. He gave us a jump start and we drove a few blocks. However, it failed at the turn lane while waiting for the light to turn. We turned it back on, bought a new battery, had it installed. On 12/29/25, my husband was driving. He turned into the intersection with a traffic light. As he was making the turn, the car simply quit. No warning. The car was dead, and blocking traffic! He pressed the start button to turn off the car, then again to turn it on. He was able to complete the turn and parked on the side of the road. By this time it had a "check engine" light on. He then drove slowly the few blocks back to our house. On 12/30/2025, the car was towed to a local mechanic. He said it threw the code PODE7, "almost certainly for a failed High Voltage battery." It was still under warranty, and we had the car towed to the dealership.…”

“While driving car stuttered check engine light and check hybrid system flashed. Check engine lights stayed on until getting home. Next day. I scanned and code p0b68 was set.”

“To the National Highway Traffic Safety Administration, I am filing this formal safety complaint regarding a dangerous engine failure incident involving my 2017 Hyundai Sonata Plug-in Hybrid. Description of Incident: While traveling on CA-85 near Mountain View, California, at approximately 65 miles per hour, the engine suddenly and without warning lost all power. The vehicle began to slow down involuntarily in active highway traffic, creating an immediate and serious risk of rear-end collision. The driver had no ability to maintain safe highway speed or accelerate out of danger. The vehicle had to be towed from the scene to the dealership. There was no warning light or prior indication that engine failure was imminent. The failure was sudden, complete, and occurred at highway speed in heavy traffic conditions. Safety Risk to the Public: This incident represents a significant and ongoing public safety hazard. A sudden, unpredictable loss of engine power at highway speed — with no prior warning — places the driver, passengers, and surrounding vehicles at serious risk of collision. This is not an isolated mechanical inconvenience; it is a life-threatening failure…”

“WHILE VEHICLE IS IN MOTION AT VARIOUS SPEEDS WITH CRUISE CONTROL ENGAGED CLIMBING UP ON HILLY OR STEEPER GRADES THE VEHICLE ACCELERATES ON THE DASH AT NEARLY 100 PERCENT POWER ACCORDING TO THE HYBRID TACHOMETER. THIS INCREASE IN POWER SURPASSES WELL OVER THE SET CRUISE SPEED. FROM WHAT I HAVE NOTICED ITS 6-10 MPH CLIMBING PAST MY SET SPEED. THERE IS ALSO A LONG DELAY IN POWER RESTORATION AFTER COASTING DOWN HILLS. I FOUND IT TO BE EXTREMELY DANGEROUS WITH THE VEHICLE AT 100 PERCENT POWER BECAUSE IT COULD CREATE A SITUATION IN WHICH YOU COULD POSSIBLY REAREND ANOTHER DRIVER OR LOSE CONTROL IN NORMAL OR ADVERSE DRIVING CONDITIONS, RESULTING IN INJURY OR LOSS OF LIFE. IN ADDITION THE ISSUE COULD LEAD TO A TRAFFIC INFRACTION. MY STATE HAS A LOT OF SPEED CAMERAS. THIS PROBLEM HAVE RESULTED FROM THE RECENT RECALL WHERE HYUNDAI INSTALLED A NEW BATTERY MANAGEMENT SYSTEM. THE VEHICLE HAS APROXIMENTLY 16400 MILES ON IT.”

“I was driving the vehicle with 2 other occupants onboard on [XXX] towards US-101. The EPS warning light already came on after entering [XXX] from [XXX], but initially, I didn't think it was much of an issue. As I merged to the right lane in preparation of entering the highway, the steering began to feel very stiff, so I immediately made a right turn into a local street when there was a little bit of steering left. As soon as I pulled over, the steering locked up completely, and both the EPS warning light and the dash display's lane-departure system warning were activated. Luckily no other vehicle or humans were endangered at the time. I put the car into park and powered it off. When I powered it back on again several minutes later, the issue resolved itself and I was able to continue driving with normal steering, and steering remained normal after several power on/off cycles which included both local and highway driving. Come to think of it, ~3 months before this incident happened, I already noticed occasional stuttering of the steering wheel and humming of the EPS assembly when the car is stationary or at low speed. I took the car to a third-party repair shop…”