2017 Hyundai Sonata PLUG-IN Hybrid

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. After keeping it for 2 or 3 weeks, they confirmed the code and that the control panel needed to be replaced. We finally picked up the car (w new control panel) on 2/20/2026. In the meanwhile, we looked up Hyundai control panel repairs on a reddit forum. We found lots of chatter about it. Turns out it's a recognized problem in Sonata and Ioniq EV and PHEV's! Clearly, a car failing in the middle of an intersection, highway, etc is a safety problem and needs to have repair/replacements made BEFORE THEY HAPPEN!

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. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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 mode. Known and Documented Defects: The 2017 Hyundai Sonata Plug-in Hybrid has been the subject of multiple recalls and class action litigation related to engine defects. My incident is consistent with the known failure patterns documented in those proceedings. Despite this history, Hyundai Motor America has denied my warranty claim, citing missed services — a characterization I dispute, as the vehicle was serviced exclusively at an authorized Hyundai dealership whenever the onboard system indicated service was due, and no technician ever identified or disclosed any engine damage during those visits. Request to NHTSA: I respectfully request that NHTSA: 1. Open or expand an investigation into engine failure incidents in the 2018 Hyundai Sonata Plug-in Hybrid 2. Investigate whether a recall is warranted

While driving at a high rate of speed propulsion to the vehicle suddenly and without warning ceased, the electric and internal combustion engine were non-responsive (ICE stopped; hybrid motor didn't provide propulsion), the warning light said "Check Hybrid System. Turn off engine" I was put at risk because I was traveling at highway speed and was given no warning before the vehicle shut down. This has occurred nine times, I've reported all to Hyundai, they have had the car in the shop three times, the issue is not fixed. No, despite ODB2 error codes, the car has not shut down while a dealership is driving it. Yes, the vehicle has been inspected multiple times by Hyundai. Yes, always "Check Hybrid System. Turn off engine", in almost all cases the check engine light comes on after that, and in some cases additional lights such as "auto hold". This first occurred in Dec 2023, I was told the car was fixed (it wasn't) and happened again in October 2024. I haven't been able to drive my car since then.

While driving the 2017 Hyundai Sonata Plug-In Hybrid, the car will begin to stall, a rapid number of audible beeps will start, the "Check Hybrid System" notification will pop up on the dashboard, and the "Check Engine Light" appears.. The car therefore cannot be driven anymore, and I am forced to pull over to the side. In order to fix the issue temporarily, I need to turn the car off and turn it back on again. Once this is completed, both the "Check Hybrid System" and the "Check Engine Light" disappears and the car can be driven again. An OBD Scanner is unable to find exactly what is going on as the "Check Hybrid System" and the "Check Engine Light" no longer appear. This has happened 4 times now within the span of 3 months. The people at risk are me (the driver), my passengers, and potentially everyone else on the road in my nearby vicinity as the problem occurs. This problem has been confirmed by the dealer in their Hybrid vehicles. This vehicle has not been inspected yet but that is an ongoing process.

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 on the next day since the Hyundai dealership appointment is a week away at the earliest. They ran diagnosis before telling me that the steering sensor in the EPS motor assembly failed, and this happened very frequently for 2017 Sonata Plug-in hybrids. This happens so often, apparently, that Hyundai issued service bulletin [XXX], but this very much looks like a recall to me, as when the system fails, steering is lost completely, and could cause great harm to myself as well as the occupants onboard, not to mention other vehicles around me. I was lucky that it happened before I entered the highway and also had a place to pull over. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

About 3 weeks ago I had just left my house, battery fully charged and gas tank full. I was coming down a hill to a stop sign and started braking. Suddenly the car seemed to lose power and essentially stopped moving. There was an error on the dash saying "hybrid system failure". There was barely able enough power to slowly pull the car over to the side of the road. I turned off the car and checked the battery in the trunk - I didn't see any obvious concerns. My husband got there 10 minutes later and we tried turning the car on again. It came on fine but there was an engine warning light. We were able to drive it without difficulty back to my house. I was unable to get a timely appointment at my local Hyundai dealer, so a couple days later My husband drove it to a local garage to see if they could figure out what the problem was. When he turned the car on again the engine light was no longer on. However, at the garage they were able to pull up a history of the car alerts and it confirmed that it said hybrid system failure. I have done some research online and it sounds like there was a recall on Hyundai sonatas hybrids for 2017 but I did not see a recall for the plug-in version of the hybrid. I searched online, however, and there were many other owners of Hyundai sonata plug-in hybrids that reported the same incident. I am hoping that a recall gets is issued for the plug-in hybrid as well so that more owners don't have the same problem. If I had been driving on the highway at 65 mph in a middle lane and my engine suddenly lost power it could have been fatal. Oh - one other recent problem I had that I'm not sure is related is that my car recently started losing electric miles very quickly. From the time it was purchased until a few months ago, it was losing plug-in miles at about 1 mi per year (i.e. each year a fully charged battery gave me 1 mile less). Then about 6 months ago it started losing electric miles very quickly - about 1/mo. Dealer said it was normal aging.

Occurrence: This has been a recurring issue for over a year (over a year, might be closer to two years now) for our PHEV Sonata. It has happened approximately 10 times. Problem: Total engine shutdown when driving the car. "Shut down engine" type error message pops up and cannot accelerate. Steering still works, but it can be hard to pull over due to lack of engine power. The car can be restarted after shutting down, but must first come to a complete stop and into Park. Safety Issue: The car stops working. Obviously, this would be quite dangerous on a busy road, a highway, or if you were taking a left turn, etc. Confirmation: The dealer indicates that the hybrid battery is a problem and should be replaced. However, due to supply chain issues, we have been waiting for over a year for the replacement. **** Reproduction Steps: **** We have found that it is most likely to happen with a fully charged battery and a sudden braking action. I suspect the issue happens when trying to charge the battery but due to its condition, it shuts down instead. It tends to happen: 1) Full Charge: Battery is fully charged overnight or "topped up" to full charge 2) Sudden Braking: Having to brake hard, such as being cut off. We have found that adjusting charging and driving habits has reduced but not eliminated the issue. Suggestion: I would suspect that having some electrical component to prevent a sudden overcharge might eliminate this problem (shunting excess current or turning off regenerative braking for sudden stops). Warning Messages: A warning message is seen, but it happens at the same time the engine is shut down and disappears before you could take a picture of it (as you are busy trying to do an emergency pull over).