25 of the
103 complaints filed about the Hyundai Sonata Plug-In Hybrid
are about the electrical system —
24% of everything owners reported.
The worst model year for it is 2016.
The high voltage battery will no longer charge neither from being plugged in to the charger on the wall nor from the buikt in system onboard the car. There are warning lights saying the inverter coolant is low but the reservoir is at the proper level. I suspect the coolant for the Hybrid charging inverter is bad and crystalizes causing blockages in the inverter coolant system. My car refuses to charge for the last 2 years. After a few seconds (about 7-10) the car shuts off the charging system when plugged in. And now that summer heat us here in the South West, it will not even charge from the regenerative braking. The high voltage battery previously would maintain 10-15% charge from the gas engine and regenerative braking. Now it's sitting at 1%. Because the battery is so low the electric motor does not produce power, and the gas engine is under powered on its own. This makes acceleration from a stop light/sign sluggish, slow and dangerous. Other Hyundai EV (IONIC and Kona) and PHEV (Santa Fe and Tucson) models have had their inverter coolant flushed and replace, some with a different spec coolant. This Sonata 2019 PHEV probably suffers from the same poor coolant and needs to be flushed and replaced by the better spec coolant fluid too. This has been getting worse and worse the last 2 or 3 years. The dealer refuses to acknowledge the problem and wants to diagnose the whole system before replacing what is obviously wrong first. The inverter coolant low level alert comes on some times, but it is not low. I haven't had time to let the dealer keep my car for days while they pretend to not know the problem and refuse to accept responsibility. Hyundai Technical Service Bulletin (TSB) exist for IONIC, Kona, Santa Fe, and Tucson models. For example the Hybrid Santa Fe and Tucson TSB is Hyundai TSB 23-01-052H-1.
NHTSA complaint #11752871 — an unverified report by a vehicle owner.
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!
NHTSA complaint #11737182 — an unverified report by a vehicle owner.
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.
NHTSA complaint #11648675 — an unverified report by a vehicle owner.
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.
NHTSA complaint #11579536 — an unverified report by a vehicle owner.
My 2017 Hyundai hybrid PHEV vehicle stuttered and failed to accelerate when the gas pedal was depressed and a warning light indicated a problem which was confirmed as a failed battery in January 2023. I was advised by the Hyundai Sonata service center 13 weeks ago that the vehicle was unsafe to drive due to a defective battery. They have not been able to replace the battery or provide an estimate of when the replacement battery will be delivered. The battery has a lifetime warranty but the Hyundai company and dealership is not providing a loaner vehicle or reimbursing me for rental vehicle while the unsafe vehicle sits in the service center for more than 3 months. Please help.
NHTSA complaint #11518172 — an unverified report by a vehicle owner.
Problem began Dec. 2021. Has occurred on 16 occasions since then. Warning light "Check Hybrid System; Turn off Engine" comes on while driving. The car then shuts off the engine and there is a 100% loss of motive power. Sometimes is associated with very rough braking with the car "knocking'." On 3 occasions there has been partial/near complete loss of braking power. All incidents have occurred while under power, so far all while under 45 mph. No accidents yet. Two near collisions from the rear. Hyundai was notified of the problem Dec. 2021/Jan. 2022. After a month of testing they stated the car needed a new plug-in hybrid battery. One was not available and due to "supply chain issues" is still not available 15 months later. Dealership provided a loaner vehicle Jan to Sept. 2022. They requested their car back and Hyundai initially agreed to cover the cost of a rental car. I rented a car for 6 weeks in Sept.-Oct. 2022 at which point a new case manager informed me that Hyundai would not pay for a rental vehicle any longer (note: they did reimburse me the cost of those 6 weeks rental). Hyundai is well aware of the safety issues involved in driving this vehicle. However, they have chosen to ignore them. Their attorney, in a letter to the Ohio Attorney General's Office, blamed the lack of a plug in hybrid battery on supply chain issues (letter was Nov. 2022, at which time the battery was supposed to be available March 2023) and only stated that my vehicle was "drivable." Another warning message "High System Temperature; Switching to Hybrid Mode" has been occurring for a couple of years periodically. Since October 2022, the malfunction indicator lamp is always on and 99% of the time the "Check Hybrid System!" warning light also comes on after about a minute after starting the vehicle. On 3 other occasions the vehicle has entered into "limp home mode" instead of complete shutdown.
NHTSA complaint #11516024 — an unverified report by a vehicle owner.
While driving the car getting error message on dashboard "Check Hybrid System Turn Off Engine", The Gas engine turn off and switch to continue on electric till able to pull on the side of the road. Turn Off engine, wait a min. Start car again and working fine. This issue appears randomly many times in the last two years while driving. Car was at dealer shop multiple times with no repair, was told we don't see active error message or they can't re-create the error. however scan show P261F error. Open Ticket with Hyundai #21018148 while car at the dealers for weeks at the time. each time told check engine got back on but not the message they are looking for.
NHTSA complaint #11514685 — an unverified report by a vehicle owner.
The vehicle has stalled in traffic numerous times since I bought it in 2016 creating a traffic safety issue. Without warning the lights on the dash will flash and the car dies. I have worried each time that traffic behind me would collide with my car. #1 1 1/2 years into ownership this occurred. They replaced part of the EV charging system that was overheating on the cars. (RECALL) # 2 1 /2 years into ownership the air-conditioner failed and the car stalled in traffic due the air-conditioner failing. (REPLACED UNDER EXTENDED WARRANTY) # 3 Last year I complained that a Hybrid Overheat Message would come on switching to EV mode and the transmission felt like it was slipping occasionally, and the battery only held 20 miles of charge, rated for 27. They refused to change the battery system under the lifetime warranty. #4 Last summer car stopped charging (REPLACED INVERETER UNDER EXTENDED WARRANTY) This month car stalled on the roadway, lights flashed on dashboard. Could have been rear-ended, Had to coast to a stop and restart the car. Took to dealer the said the replaced an EV computer for 5K (REPLACED COMPUTER UNDER EXTENDED WARRANTY) 3 days later same issue, stalled on busy street without warning. Took to dealer and the replaced the cars main battery, charging me $450.00 3 Days later it stalled again without warning in traffic, It's not back in the shop. THIS VEHICLE HAS MAJOR SAFETY PROBLEM. IT'S EXTREMELY DANGEROUS TO HAVE A CAR STALL IN TRAFFIC WITHOUT ANY PRE-WARNING. THE DESIGN IS DEFECTIVE. THE CARS NEED TO BE RECALLED AND BOUGHT BACK AT FULL PRICE BY THE HYUNDAI.
NHTSA complaint #11506083 — an unverified report by a vehicle owner.
While driving the hybrid system warning light comes on and says to check hybrid system, vehicle goes into limp mode will not accelerate over 25 mph and codes need to be cleared before vehicle van be driven. This has caused me to almost have several accidents. The vehicle slows down and gives no warning prior to this occurring. It has started happening more frequently vehicle currently has 85k miles.
NHTSA complaint #11500417 — an unverified report by a vehicle owner.
I was traveling on a highway when a "hybrid system warning" suddenly appeared on the dashboard. Every dashboard warning light illuminated. The car began to lose power. I exited the highway immediately and the car began to have sporadic power and was "lurching." I immediately pulled onto the shoulder and at that time another warning on the dash appeared within a minute or two of the first warning that said "shut engine off." The computer screen began to flash on and of and the windows would not roll up smoothly. When the tow truck arrived the car wouldn't start and it didn't recognize the key fob. Hyundai now has the vehicle and claims the car needed a "software update", but they cannot tell me if it will ever happen again and cannot tell me why the car goes into critical failure when it needs a mere software update. This is the second time this has happened. The first time it was repaired under a voluntary recall campaign about a year ago. This is an extremely dangerous occurrence as the car loses power without warning. I was fortunate to be near an exit when it happened and able to safely get off the highway, but that was just luck. The manual indicates that a hybrid system warning means that the car can potentially go on fire.
NHTSA complaint #11492604 — an unverified report by a vehicle owner.
My 2016 plug in hybrid Sonata repeatedly inidcates that there is "high system temperature switching to hybrid mode." This first happened on my first long trip in the car in 10/21 and has happened repeatedly since. This happens at all temperatures, including moderate temperatures (mid 70s). It seems to happen randomly, such as when battery has several miles of charge left in it, when it is fully discharged, and repeatedly when the car is already running in hybrid mode, which a driver could interpret means that the engine is about to shut down, as I did on a long trip. I have taken it to two separate dealers, and the only thing they did was replace the fuel pump, which did not solve the problem. In addition, the battery life has reduced greatly, despite the fact that I always fully discharge and recharge the batter. As you can see from the attached Hyundai forum comments, this appears to be a prevalent problem for this make and model car and no relief from the manufacturer appears to be on the horizon.
NHTSA complaint #11478763 — an unverified report by a vehicle owner.
"TAKATA RECALL" AUGUST 25TH THE CAR WAS DRIVEN INTO SOME HIGH WATER AND WAS PARKED BY A GAS STATION NEAR GREEN ROAD AND ALDEAN WESTFIELD R. THE CAR WAS UNDERWATER FROM THE FRONT END. I HAVE TAKEN THE VEHICLE IN FOR REPAIR MULTIPLE TIMES FOR REPAIR. FROM WARRANTY ISSUES TO FLOOD REPAIR, BOTH CAN'T GIVE ME A STRAIGHT ANSWER TO WHAT IS WRONG WITH THE CAR. THE CAR STOPS AND COMPLETELY SHUTS OFF HYBRID MALFUNCTION. WE DONT HAVE ANY DOCUMENTS, THE DEALERSHIP HAS COPYS OF ALL REPARS.
NHTSA complaint #11144863 — an unverified report by a vehicle owner.
THIS IS THE PLUGIN HYBRID MODEL. THE LITHIUM ION BATTERY CANNOT BE CHARGED SOMETIMES DUE TO OVERHEATING CONDITION. IF THIS IS NOT FIXED, IT MIGHT CAUSE A FIRE OR EXPLOSION. SOMETIMES, IT WILL NOT LET YOU CHARGE. IT WILL NOT EVEN LET YOU TURN OFF THE CHARGE SCHEDULE TO CHARGE. SOMETIMES, IT STOPS CHARGING DUE TO THERMAL PROBLEM. HYUNDAI IS NOT TAKING RESPONSIBILITY TO FIX THIS. ATTACHED PHOTO DOCUMENTED THAT IT DID NOT ALLOW ME TO SWITCH OFF THE CHARGE SCHEDULER TO START CHARGING. I HOPE HYUNDAI WILL ADDRESS THIS PROBLEM BEFORE THE CAR BURNS UP OR EXPLODES.
NHTSA complaint #11102589 — an unverified report by a vehicle owner.
I WAS GOING ABOUT 70 MPH IN FULL ELECTRIC MODE AND THE CAR REMOVED ALL POWER FROM MY GAS PEDAL, THERE WAS LOTS OF DINGING SOUNDS AND THE DASH SAID "CHECK HYBRID SYSTEM, TURN YOUR CAR OFF". LUCKILY I WAS ALREADY TO THE FAR RIGHT SO I COULD JUST PULL TOT HE SHOULDER AND STOP THE CAR, THE BREAKS AND STEERING WERE STILL WORKING. TOWED TO THE DEALERSHIP, HOPING THE MARCH 2018 RECALL IS THE FIX. I HAD TO CALL AAA, ALL BLUE LINK CAPABILITIES STOPPED WORKING AS WELL. 2016 PLUGIN WITH ABOUT 25,000 MILES.
NHTSA complaint #11099959 — an unverified report by a vehicle owner.
THIS IS 4TH TIME THE "CHECK HYBRID SYSTEM" LIGHT CAME ON IN LAST 7,000 MILES OF DRIVING. HYUNDAI CLAIMED TO HAVE FIXED THE PROBLEM THREE TIMES SO FAR BUT IT KEEPS HAPPENING AND SINCE THEY ARE UNABLE TO REPAIR IT UNDER WARRANTY, THEY MUST BUY THE CAR BACK. ONE OUT OF THE FOUR TIMES, THE CAR COMPLETELY DIED ON THE ROAD PUTTING LIVES ON THE LINE. A COMPLAINT WAS FILED EARLIER (REF: HYUNDAI CASE #111109600, NHTSA COMPLAIN #11080680) BUT NO ACTIONS WERE TAKEN BY EITHER HYUNDAI OR NAHTSA. THIS CAR IS UNSAFE TO BE ON THE ROAD AND CAN NOT BE FIXED AFTER THREE TRIES WITHIN A YEAR.
NHTSA complaint #11093231 — an unverified report by a vehicle owner.
TL* THE CONTACT OWNS A 2017 HYUNDAI SONATA HYBRID. WHILE DRIVING APPROXIMATELY 20 MPH, THE FRONT SIDE COLLISION WARNING SYSTEM FAILED TO FUNCTION. THE VEHICLE WAS TAKEN TO STEVENS CREEK HYUNDAI (4425 STEVENS CREEK BLVD, SANTA CLARA, CA 95051), BUT THE FAILURE WAS UNABLE TO BE DIAGNOSED. THE VEHICLE WAS NOT REPAIRED AND THE FAILURE RECURRED. THE MANUFACTURER WAS NOT CONTACTED. THE APPROXIMATE FAILURE MILEAGE WAS 13,000.
NHTSA complaint #11089955 — an unverified report by a vehicle owner.
WARNING LIGHT SAYING "CHECK HYBRID SYSTEM" COMES ON AND THE ENGINE WOULD NOT START IF THE CAR IS PARKED. WHILE DRIVING THE CAR COMPLETELY SHUTS OFF WITHOUT THE ABILITY TO PULL OVER AT A SAFE LOCATION. IT HAPPENED TO ME THREE TIMES SO FAR, TWICE UNDER 18,000 MILES AND ONCE AT 24,600 MILES. THE DEALER IS NOT SURE WHAT IS CAUSING IT AND GIVES IT BACK TO ME AFTER SOME TWEAKING TO GET RID OF THE WARNING LIGHT. I HAVE FILED A COMPLAIN WITH HYUNDAI (CASE # 11109600) REGARDING THIS. THIS CAR IS A DEATH TRAP AND I WILL NOT EITHER DRIVE OR RIDE IN THIS CAR EVER. I WILL NOT BE SATISFIED IN ANYTHING LESS THAN A COMPLETE BUY BACK. I AM ASKING NHTSA TO FORCE A RECALL AND HAVE THEM FIX THE PROBLEM WITH CONFIDENCE OR DO BUY BACKS. IT'S A DEATH TRAP AND CAN NOT BE ALLOWED TO EXIST ON THE ROAD.
NHTSA complaint #11080680 — an unverified report by a vehicle owner.
ON 1/7/2018 WE WERE DRIVING OUR 2016 HYUNDAI SONATA HYBRID WITH APPROXIMATELY 41,100 MILES IN IT TO LOS ANGELES, CA WITH MY 82 YEAR OLD FATHER ON OXYGEN FROM SAN JOSE WHICH IS ABOUT 370 MILES AWAY ON HIGHWAY I5 WITH THE SPEED LIMIT OF 70 MPH. WHEN WE EXPERIENCED ENGINE PROBLEM. WHILE EXITING TO OUR DESTINATION ON HIGHWAY 118 DE SOTO EXIT, THE ENGINE HAD SLOWED DOWN IN THE MIDDLE OF THE INTERSECTION AND BARELY TURNED TO THE SIDE OF THE ROAD FOR SAFELY .WE WERE UNABLE TO START THE CAR AND DASHBOARD HAD INDICATED TO CHECK HEV . SEVERAL ATTEMPTS WERE MADE TO START THE CAR, TO NO SUCCESS. LIGHTS WILL COME ON DASHBOARD, STILL ABLE TO CONNECT TO BLUELINK TO CALL FOR ROADSIDE ASSISTANCE BUT THERE WAS A LONG WAIT BEFORE A CUSTOMER SERVICE ANSWERED UNTIL THE ENGINE COMPLETELY DIED AND STALLED. WE WERE STRANDED WITH AN 82 YEAR OLD MAN WHO HAS RESPIRATORY ILLNESS AND WE HAVE FINALLY CALLED AN UBER TO HIS HOME BEFORE OXYGEN RUNS OUT. ROAD ASSISTANCE FINALLY CAME AFTER 2 HOURS OF WAITING AND THE CAR WAS FINALLY TOWED TO THE NEAREST HYUNDAI DEALER IN WOODLAND HILLS 20539 VENTURA BLVD WOODLAND HILLS .THE CAR IS BEING SERVICED AND HAS NO UPDATE YET. I CALLED HYUNDAI USA CUSTOMER SERVICE AT 1-855 671 3059 THIS AM 1/8/2018 AND CLAIMED THERE HAS BEEN NO REPORT OF RECALL TO THIS SORT OF PROBLEM AND HAS THEREFORE GAVE ME A REFERENCE CASE #10911352 .
NHTSA complaint #11061171 — an unverified report by a vehicle owner.