2021 Hyundai Sonata Hybrid Problems & Complaints

See attached document for complaint.

Owned car since 09/2024 with 64K miles. Battery system (12V/hybrid system) has shut down and died 47 times since 04/2025 - no shut downs before then. Car with ~69K miles at that time. Dealer had car six weeks (05/17 to 07/05/2025) and it died “a number” of times and report that Hyundai claims this is “what the car is supposed to do.” Since 07/05 it has died 12 times just sitting in my driveway or the lot at work. This is NOT normal. Internet blogs show DOZENS of other Hyundai hybrid owners reporting the exact same issue. Car now with 75K miles and under warranty. Dealer will not replace battery system.

This is on my 2021 Hyundai Sonata Hybrid Limited - for the 7th time the vehicle has been completely dead and unresponsive. I have had to gain entry to the vehicle using the manual key and press the "jump" button to get the vehicle to start. The Hyundai dealership ran a bunch of battery updates to the 12 volt battery several weeks ago and said that should hopefully fix the issue. Several weeks later on 07/19/2025 the vehicle was dead again. I had to use the key to manually gain entry and jump the car again. The dealership said that the 12 volt battery may need to be replaced and said that it is fully integrated with the hybrid battery system which is covered for 10 years/100K miles whichever comes first. I am still within the warranty period so hopefully Hyundai will fix the issue. From an online search, it appears this is not an uncommon issue with the Hyundai Sonata Hybrid. I am waiting on Hyundai for a fix and for .

What component or system failed or malfunctioned, and is it available for inspection upon request? RANDOM TOTAL ELECTRICAL FAILURE (DOORS WON'T UNLOCK, CAR UNRESPONSIVE) How was your safety or the safety of others put at risk? DIFFICULT TO GAIN MANUAL ENTRY TO CAR, PARTICULARLY IN DARK SITUATIONS Has the problem been reproduced or confirmed by a dealer or independent service center? NO, I HAVE TAKEN THE CAR IN FOR SERVICE TWICE AND THE ISSUE HAS NOT BEEN CORRECTED. THE CAR IS BACK AT THE DEALERSHIP NOW FOR A THIRD ATTEMPT. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? YES Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? NO As a reference: [XXX] Key Takeaways from the Thread: Several 2021 Hyundai Sonata Hybrid owners (and a few Ioniq and Elantra Hybrid owners) are reporting the exact same symptoms: Random total electrical failure (doors won’t unlock, car unresponsive) Requires manual key to enter 12V battery reset button inside vehicle restores power No error codes or permanent fixes from dealerships Issue occurs sporadically, making it difficult to replicate or diagnose Some dealers have replaced the 12V battery or DC-DC converter, but results are mixed No formal recall exists yet, despite growing reports INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Every day the car is dead, have to take the manual key out pop door cover off unlock car manually push the 12v reset button and hold fob to start/stop button for car to work again. Happens daily.

12v battery dying randomly

Air flow check engine light alerted and source was faulty fuel injector which required replacement of 4 fuel injectors.

Overheated engine alarm came on while I was on the freeway on a rainy day. Vehicle was towed to Hyundai dealership in which service technician found that the part preventing water from leaking into the muffler was broken. Hyundai dealership has ordered replacement part but it is on backorder. The broken part that needed replacement has been on backorder for close to a month and there is not an ETA of when the part will be received. Prior to the overheated engine alarm going off, cold air was blowing out of the vents even when the heat option was selected.

Coolant system leaks in to the engine or exhaust system, which is evident in white smoke exhaust and coolant level dropping. In my situation, I required an entire container of coolant to perform a daily commute, and the reservoir was empty by the time I made it to the dealership. Car is rendered undrivable due lack of coolant and engine overheating. My car was in the dealership repair facility for 6 weeks awaiting parts on back order due to nationwide shortage. A technical service bulletin has been issued for this manufacturer defect (23-EM-009H). Cost of repairs was roughly $2,300.

My 2021 Hyundai Sonata Hybrid seems to be leaking coolant into the exhaust system. Various reports online indicate that this is a consistent issue with 2020-2022 Hyundai Sonata Hybrid models. A lot of the reports indicate that owners have tried getting theirs cars repaired for the same issue I have a various dealerships all across the US, but either haven't had any luck or have had a temporary fix for the issue, which proceeded to occur again every couple of months. I personally have had my car inspected by my personal dealership and they have confirmed the issue and have mentioned that other owners have brought theirs in to be checked out, but haven't really had luck. I believe that Hyundai should take responsibility for this and issue a recall on the affected models. I bought the car in good faith hoping for reliability but haven't had it for even 6 months now and this problem is here. For safety or myself and others on the road, this models of the Sonatas need to be recalled and repaired IMMEDIATELY. For reference, here is a reference for the complaints people have made online regarding the vehicle: 1. [XXX] 2. [XXX] . (THE RESPONSES HERE ARE VERY DETAILED) [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

EHRS Coolant Leak- problem started in [XXX] when engine overheated. The weather in Michigan in inclement and being stranded in the intense cold can lead to loss of life. I had it towed to a Hyundai dealership that was unable to find the problem and in attempting to "find a leak" used the incorrect dye, necessitation transferal to another more competent dealership where the problem was diagnosed and was fixed with a replacement part. In December 2023 a TSB 23-EM-009h was issued by Hyundai describing this problem and issuing a part (Center Muffler). I was not informed and the problem recurred. currently this is the third episode and Hyundai after paying 95% of the previous cost, now only agrees to pay 85% and denies reimbursing me for the car rental. Warning lights appeared with all 3 occurrences. Hyundai should have issued a recall to obviate this. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

the car randomly goes into dead or limp mode and unable to start. need to jump start it to come alive. No codes shown once its jumstarted. it has happened at random on several occasions.

When the vehicle is turned off the 12v Lithium battery will die. This is a intermittent occurrence that has happened approximately 7 times since [XXX]. Today is December 12, 2024. The car is currently at All Start Hyundai dealership in Pittsburg, CA. This dealership initially denied the car had a problem because they could not duplicate it in a 24 hour period and told me "the car is operating as designed". When I insisted they check the health of the battery, the service department would not do this until they received technical advise from Hyundai headquarters (HQ). It is a multistep process to get to the battery and requires removing the back seat. When HQ advised the battery check, the service department found the battery was swollen and needs to be replaced. I have found information on chat boards and YouTube where other car owners having the same issue. Why hasn't Hyundai HQ issued a recall and replaced all the batteries? The dealership has told me there are batteries in inventory in a warehouse in Los Angeles California, yet HQ has them on hold on back order status. What and why would the battery not be available for the cars having the issue? I believe a swollen 12v Lithium battery is a safety hazard and should be recalled. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

On three separate occasions, while going very fast (60-78 mph), the automatic emergency braking system turns on. The warning lights flash and there is some type of warning noise. I don't even know if it starts to break because it scares me so much, I just press the gas. It turns off within a couple of seconds, but that is not the point. If I didn't react so fast, I am unsure of what could actually happen.

The BMS module within my cars hybrid system failed causing a parasitic drain on the hybrid battery. The dealership where the work was performed would have to be contacted for pictures. The hybrid battery system swole to a dangerously inflated level and did not produce any codes for an OBD reader to pickup. This has caused the dealership to turn my car away multiple times before finally performing the in depth inspecting required to verify battery swelling. This is a known problem throughout the internet I searched "2021 hyundai sonata hybrid battery dying every day" reddit has plenty of user with the same issues. I am not aware of who has inspected my battery besides the dealership. There was no warnings at all the only reason my battery was finally looked at is because of my persistence.

The contact owns a 2021 Hyundai Sonata Hybrid. The contact stated that the key fob was inoperable and after using the key to manually open the door. The contact stated that the vehicle failed to start while pressing the START/STOP button. The vehicle was towed to the local dealer, but the cause of the failure was not determined. The contact was advised that when the failure occurred, to start the vehicle, the battery reset button should be pressed before pressing the START/STOP button. The manufacturer was not contacted regarding the failure. The failure mileage was 24,000.

On three separate occasions over the last two months, while driving, an alert comes on that says check hybrid system then the vehicle powers off. When this happens, you lose the ability to accelerate break steer, and I have been lucky each of those three times and that I was in a situation where there was not much traffic. I am not able to drive the vehicle at this time. I have reported the problem to Hyundai and they want me to drive the vehicle to the dealership for another check of it. They have looked at it once before and have not been able to diagnose a problem. It is unsafe to drive and they are not willing to assist in getting the vehicle to the dealership without me getting it over there.

Coolant leak acting like blown head gasket. Coolant was leaking into the exhaust system. Defective EHRS system

The car randomly loses power and stalls on the expressway and it states that something is wrong with the hybrid system

The vehicle, after parking, is nonresponsive to the key fob, nor will it start. This can happen at anytime and anywhere. Dealer said "It is possible the integrated 12v battery into the hybrid battery may be faulty. No codes or tests can confirm the issue. The dealer said the key fobs tested ok." My wife works late at night in a dark area, this has happened 2 times at her place of work and we are concerned for her safety as she has to wait outside for a tow truck to tow it to the dealer. The first 3 times it occured, this issue started around march of 2024, and repeated every 30-45 days. Now it has happened 2 more times in the last week. No warning lamps or indications of problems. The windshield has distortion within the glass and is not a clear view. It is as though you are looking through the heat of a jet engine trying to focus on what is on the other side. This is a major distraction while driving, reading the heads up display in the car, reading street signs and general navigation of pedestrian and other vehicle traffic. There is no aftermarket film or materials on the windshield. The door handle on the drivers side has a cover plate over the hole where a manual key could be inserted. As a construction worker I have very strong hands and I have a difficult time removing the cover plate. The last time I removed the plate I cut my hand on the interior part of the handle as the cover plate popped off. That is how hard the plate is to remove. My wife cannot remove the cover plate on her own. This system is in place for the manual use of the hidden key inside the key fob to be able to open the door in the event of a power failure of the vehicle. which has now happened randomly 5 times.

My battery has died twice, so dead that I can’t even unlock to car with the remote. The first time I had it jumped and took it to the dealership where they were unable to find anything wrong with it and they told me if it happened again to have it towed in so they could diagnose it while the battery was dead. So that happened again and I had it towed in to the dealership in early April. It’s now July and they still have my car and don’t have a diagnosis yet. They have had their field engineers out to run all sorts of tests, but nothing yet. Today they told me they have 3 Sonata hybrids there with the same issue as mine.

Randomly the car will get a message when driving starting “ Check Hybrid system. Turn engine Off” and the car isn’t able to accelerate when this happens. When you cut the engine off the car is unable to start again until it is jumped. I’ve confirmed the battery isn’t the issue however something with the vehicle is wrong. There are many accounts of people online dealing with the same issue.

215/55R17 94V BSW. . Contacted Michelin about two (2) of the four (4) tires DO Not have the date of manufacture on side wall. These tires are direction specific. They should known that. Maybe the date of manufacture is on the inside wall but they should known the the tire is DIRECTIONAL and be on Both sides. I am not going to jack up my vehicle and remove the tire to check the code (IF it is only on one sidewall). Will Return tires to Costco where purchased. Michelin has not responded to my emails...

Driving 70 mph, warning lights and alarms "Hybrid System Failure" "Vehicle shutting down" and then it does. No lights, no hazards, no power. Push button battery restart starts it again with no visible issues. Driving 30 mph, warning lights and alarms "Hybrid System Failure" "Vehicle shutting down" and then it does. No lights, no hazards, no power. Push button battery restart starts it again with no visible issues. Driving 58 mph warning lights and alarms "Hybrid System Failure" "Vehicle shutting down" and then it does. No lights, no hazards, no power. Push button battery restart starts it again with no visible issues. ^This is an ongoing issue. It's also been powerless several times while parked.

Driving on the freeway when we got a notice on the dash that we needed to pull over and the vehicle shut down due to a fuse,/battery issue.

My car will power off randomly, or will seem as though there is no power. I have to revert back to the manual key to enter the vehicle and hit the 12vlt reset to power it back on. This happened at least 3 times. Once while operating the vehicle, and twice while the vehicle was left parked. This is not a low battery issue as, the car will only do this occasionally, and not every time I enter and turn on the vehicle. There is no error code to follow this mishap as all power goes out and the dealer maintenance has nothing to work with.

Integrated 12v battery in hybrid system keep draining out. I have to manually open the car and reset it every time in order to be able to drive.

The Battery dies randomly and requires the physical key to unlock the door. It is a hybrid, so it has a 12 volt battery button that jumpstarts the car. While driving the vehicle, the battery meter on the dashboard will show a near-full battery and then a near-empty battery within a few minutes. This vehicle was bought brand new from a Hyundai dealership and for the first 2 years, there wasn't an issue. The past few months, the battery issue started.

the car keeps randomly dying (not during driving "yet") it happens at least once or twice a week of where i go to ride my car and it is completely dead, i have to unlock the door using the key fob manually and push the "Reset 12v battery button" inside the car. i have tried to have Hyundai service repair the issue or at least tell me what's wrong but no hope as they can never replicate the problem. I am seeing alot of users posting online on numerous web forms (reddit,facebook..etc) that they are having the same exact issue as me for the same exact model of my car, With also no help from the dealer on the matter. This must be a defect at some point and would greatly appreciate if NHTSA can help push this issue to the dealer

The Battery dies randomly (like I have to open the car with they physical key to access the car dead) there isn't a pattern. I have taken it to the dealership and they can't diagnose it because they cant replicate the issue and say nothing is wrong. Sometimes the car dies while I'm INSIDE and just having lunch while the car is off.

Integrated 12V battery dies with no warning and requires manual keyed process to get in to the vehicle. Once inside, the battery reset button needs to be pressed to have the solar battery start the vehicles electric system. After a few minutes the engine takes over to start charging the battery. I have had the battery die 3 times on the 2021 Hyundai Sonata Hybrid in one week. Other postings online indicate others owners are having issues with the battery also with one owner loosing power while operating the vehicle on the freeway. After safely coasting the vehicle to the shoulder, the reset battery button restarted the electrical system for the car. Possibly an issue with the 12V battery implementation with the solar battery?

Initially had loss of cabin heat. Later, vehicle randomly overheated. Repair shop replaced EGR due to finding confidant buildup of water/coolant mix. Within one week, problem returned. Dealer notified me that while replacing another part they found a TSB for coolant leakage into exhaust that was consistent with my issue. After research, it is clear that this is a widespread failure and should be a recall.

Hyundai 2021 Sonata Hybrid. Blown head gasket. Reported 1,000 miles after warranty expired. Car was in the shop for Hybrid battery issues. Repair completed. 2 weeks later smoke coming from the exhaust. Hyundai says blown head gasket - will not honor warranty as I was just a few thousand miles over warranty. Seems to be a common problem with the Hyundai not honoring the warranty.

Antifreeze is coming out of the exhaust. Heater is only blowing cold air. Repair shop said it is a common problem with the Hyundai hybrids. Was told I had to take it back to the dealership. The y repair shop said this is very common and is wondering why a recall has not been issued by the NTHSB. Dealership has been unresponsive.

The vehicle has been turning completely off after use for over a year now. At first it would happen every now and then at the beginning and all you'd have to do was restart the car manually. Now every time the car is turned off it needs to be restarted manually now. The car will also shut itself off while you are driving. It will tell you something is wrong and then won't let you get over 15-20 MPH. If you are on a neighborhood, it's less dangerous for this to happen where you can pull over and turn off the car and restart it. But I have seen other post that they've started to malfunction on the freeway and highways before. My car is a 2021, but recently I've seen 2023 models are doing this as well. I know some people on the internet have gotten their car fixed by replacing a back logged battery. It took some people over a year to get it diagnosed correctly and 6 more months to get a new battery. I assume this is also what is wrong with my vehicle. It is in the shop right now, but we have not gotten an answer back even htough it's been there for 10 days. The car app has also indicated that the car has not been turned on since we left it there.

My vehicle's heat stopped working suddenly. A short while later, I received and overheat warning for the engine. I had to stop repeatedly on the shoulder of the highway to allow the car to cool so I could move it to a safe space at the next exit. The dealer has confirmed that the coolant was leaking into the exhaust system and burning up. This resulted in white smoke, inconsistent power, and a stumbling engine when it would switch over from the electric to the gas engine. This problem comes on suddenly and can leave you in a very bad situation since there is no warning to this problem. The dealer reported my car had no coolant left in it which is why it was frequently overheating. I have read about this problem on many online forums and it seems to be very common in this car. Hyundai needs to create a fix.

While driving, engine alerted that it was overheating. Pulled over and coolant was very low, so I refilled it and then while driving to my family's garage to use the lift, saw white exhaust smoke. Took it to an independent mechanic, and in the ~10 mile trip there, over a quart of coolant had been burned off. He was able to reproduce the issue. No issues with the engine operation, it runs well and efficient, no check engine light. Mechanic found that a coolant line runs to the middle of the exhaust system and that this seems to be the issue. Other owners seem to have reported this same issue with this same model and roughly the same year, in which the muffler assembly needs replaced due to coolant leaking into the exhaust. Only prior issue was less warm air out of the vents for the previous week or so, but no other issues or warnings.

the coolant reservoir has been dropping showing levels below min even after topping it off

My 2021 Sonata Hybrid Limited has been in the shop for over 3 months. At least 4 times while driving on city streets, I'd receive an error stating problem with hybrid system please turn off vehicle. Car would go into limp mode giving me just enough power to pull off to the side of the road (if possible), then completely shutdown. Fix action is to hit jumpstart button to get the power back to the vehicle in order to power it on again. After those issues battery constantly died and I had to use the physical key to open the door and hit the jumpstart button to get power. Dealer (Hyundai Jim Click East, Tucson, AZ) couldn't find an issue initially stating they could not replicate what I was experiencing. But eventually my patience ran thin and they finally identified a voltage error while in the service department. The rep informed me that the issue lies with the 12v battery which is integrated into the hybrid battery (stupid design). Service tech had to order a 12v battery from Korea (after dismantling the hybrid battery and sending the pics to Hyundai for approval). This was [XXX]. Still waiting on the parts, no updates at this time. There was another sonata hybrid limited like mine also at the dealership for the same issue. This vehicle had been there since June. They were able to get a new battery for that vehicle, however after a week the same issues reoccurred. I've noticed on Reddit forums that many 2021-2022 sonata hybrid limited owners have been experiencing the same issue, with the same long wait times from Hyundai HQ regarding a solution. At this point I believe it'd be best to open an investigation as there it's been difficult for the dealership and the owners to get any answers from Hyundai regarding this issue. I'd also suggest a recall for this vehicle as it's clearly a widespread problem and hopefully that will give Hyundai the kick in the ass needed to actually take this seriously. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Battery keeps dying randomly. Approximately once every other week and I drive 12k miles a year… dealership reassures me it’s find. Found numerous reports of other Sonota Hybrid users experiencing a similar issue.

Discovered that I had no engine heat to use in the cabin with cooler outside temps. Checked coolant tank. Was nearly bone dry. 2021 hybrid is under warranty with only 35K miles on it and regular scheduled maintenance. Have also noticed puffs of white smoke upon easy acceleration and switching from battery to gas. Refilled engine coolant, but it continues to leak internally with use (no evidence of pooling under car) with short mile trips. Had to leave at dealership for repairs and cannot get a repair date for another month out. Other hybrid owners of 2020 and 2021 report their dealerships discovered the coolant is leaking into the engine and mixing with the exhaust (thus the white smoke). I am adding my car to the list of others who have reported the same problem.

This car is a Hybrid The car has a 12V battery reset system which stops the 12V battery from draining to zero voltage. This is a design feature. However, since purchasing this car we have had Hybrid Engine Failure warnings happen 3 times, in 2 months. When this happens the car engine shuts down, no matter at what speed you are driving! The car gives a warning on the dashboard that states - Hybrid System Failure - and the engine shuts down. The dashboard goes completely bland as all electronics are switched off. This has happened 3 times, 2 of them occurred on the freeway at high speed. Luckily we were able to pull over without being impacted by another vehicle. After a few seconds of stopping we are able to push the 12V Battery reset switch and the engine restarts when the start button is depressed. After the first incident the car was given to the local Hyundai dealer and they found nothing wrong with the car. It has happened twice since the car was returned to us and the car is currently in the Hyundai dealership, a different one, for diagnosis. We do not want to drive this car until the fault is determined and corrected

The contact owns a 2021 Hyundai Sonata. The contact stated that while driving at an undisclosed speed, he received an alert indicating that the engine was overheating and to pull over. No warning lights were illuminated. The contact then veered to the side of the road and waited approximately 15 minutes before restarting the vehicle. The vehicle was then taken to the dealer where the vehicle remained. The vehicle was diagnosed, and it was determined that the engine coolant bypass valve needed to be replaced. The vehicle had not yet been repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 32,547.

Incident sounds similar to those experienced with the dual clutch transmissions. November 2022, all of the vehicle warning lights were on and remained on. The vehicle would not move and the transmission selector/shifter was locked in place. Working with the local service/dealership, the vehicle was repaired after 3 weeks with a new transmission shift actuator (or possibly other part). Similarity in the experience and possibility of risk with little information about trends or others in similar situations or resolution. We've had another (Same make/model/year) vehicle present similar circumstances.

When I arrived in the parking lot and selected the R (reverse), the vehicle stayed in the D (Drive) although that it was moving backwards and was able to park it. The shift selector was stuck in DRIVE (Drive) leaving the vehicle on but not operational. After several attempts to allow the vehicle to cool and the battery to reset, (30 minutes_ later), the car started and took the vehicle to be serviced. The vehicle technician said they had a difficult time diagnosing the vehicle because it was giving different codes. They said that while testing they found the Transmission Shift Selector Module was damaged. Not physically but electronically damaged. They also stated that the car could have other problems but that they needed to replace the module first because it could be the cause of the other errors.

The cabin heater started blowing cold air in February. One shop said the car was low on coolant and topped it off. I made an appointment to take the car to a dealer because it's still under warranty (<37k miles). I had to wait 3 weeks. A few days before my appointment, the cabin heater started blowing cold air, again. There is no indicator that the coolant is low. The engine temperature is one of a dozen gauges one can scroll thru, but the "engine overheating" warning started flashing before I thought to check the temperature guage. Smoke came out of the exhaust and, once stopped, from under the hood. There was a risk of an engine fire and/or permanent damage to the engine.

Engine oil plug backed out while driving causing loss of all engine oil in the mountains. Drive time was one hour when oil lamp turned on as we reached our destination. Oil check stick had no oil on it and the whole undercarriage and rear of the car was covered in engine oil. Made an attempt to refill oil and plug fell all the way out and poured the new oil onto the ground. The oil plug is not visible or accessible due to a plastic cover on the underside of the car. The vehicle was towed to Elk Grove Hyundai dealership for service since they were the last hands on the car for regular maintenance. It was confirmed by the dealership the oil plug backed out on it's own. My family's safety was compromised as we were driving at night in steep mountains during high traffic time. There would be nowhere to go if the engine ceased and would cause an accident on HWY 50 in California. Also a full six quarts of oil was leaking on the back roads, highway, and residential roads, and eventually in a high school parking lot was were the bulk of the oil was spilled. The is an environmental hazard at public school Eldorado High School.

The forward collision warning, automatic emergency braking and adaptive cruise control failed as the first 2 activated when there were no oncoming collisions in front of me and the nearest cars around me were 1/4 of a mile away. The cruise control failed as it turned back on after the vehicle veered off the highway and into the rest stop. My safety and the safety of a lot of other people in the rest stop were put at risk because the system malfunction and tripped when no other cars were present that would have led to a collision. The vehicle led me off the highway into the rest stop where others could have been fatally hurt. I ended up with a shattered left foot that required a major reconstructive surgery to mend but the break will affect me the rest of my life, with more problems developing later on in life as well. No one inspected the vehicle or listened to what I had to say. No investigations were launched by insurance, the manufacturer or the police. If anything, insurance and the manufacturer seemed like they were in a hurry to dispose of the vehicle, urging me to release vehicle where it was sent to after the crash to one of insurance centers. The collision warning light came on and the vehicle responded by hard braking and veering to the right, then the cruise control turned back on and accelerated into the rest stop, first bouncing up the curb and onto the dirt, hitting a sign on the passenger side then bouncing off a tree on the driver side and finally T-boned a parked boat on a trailer head on. The vehicle was a total loss

Very loud car alarms sounded, e.g., it sounded like a something like a red alert in an old Star Trek episode. warning light indicated engine overheated, extreme exhaust/smoke bellowed out from rear of car while decelerating on highway exit ramp. My wife and I were inside the car during this event. This event happened on 5 pm EST December 9 at Hamilton Avenue exit on Ohio 126 Cross County Highway (Ronald Reagan Highway) in the Cincinnati metropolitan area. Had to park car within one mile. I had the car towed to the nearest dealer after it had cooled for 1 +hour. I was afraid the engine was going to explode or catch fire as I was decelerating. The dealer suggests the heat exchanger needed replacement. However, after 45 days, Hyundai has not shipped the heat exchanger that I have been made aware. I am concerned this event may be likely to reoccur and with resulting potential injuries to the occupants inside.

On Wednesday, October 6th, I was driving full speed (65mph) on a major highway. Multiple lights on the dashboard came on. The LCD display screen for music, apps, etc. went black. More lights came on and others went off on the dash display. I let off the accelerator and steered the car. The fuel efficiency was wilding jumping back and forth. Soon enough, all the lights went back off, but the mileage gauge (fuel efficiency) continued to jump wildly. The brakes seemed to respond differently- almost as if there was a delay between me pressing the brake and the brakes catching. When I needed to accelerate, the car seemed to be having trouble switching between the electric and gas motors. I was able to drive to a safe location and shut the car off. This was terrifying, as the car's computer system or electrical system clearly failed, even if temporarily. The car was taken to the dealership immediately. The car's mileage is under 4, 500 miles and was purchased in February 2021. There have been other small issues but never anything like this. The display screen has gone black before a few times, my cell phone won't connect (even manually and it's properly connected, working seamlessly other times). In those cases, I shut the care off and restarted it to fix the issue. However, this new incident is terrifying and unacceptable. Including photos taken that show impossible fuel efficiency as only evidence I could safely capture.