2018 Hyundai Sonata Problems

The lower aluminum engine oil pan developed a structural hairline fracture ("micro-crack") directly along the factory casting ridge adjacent to the drain plug. The component failed without any external impact, road hazard, scraping, or underbody damage. The failure was officially confirmed and documented by Eckert Hyundai during a service visit on July 13, 2026 (Case #42971835). Following the dealer oil service, the fracture degraded into an active, worsening oil drip that requires a catch tray under the vehicle to capture leaking fluid. The vehicle is currently available for inspection. Safety Risk: An active engine oil leak poses a significant safety hazard. Rapid or continuous loss of engine oil can cause sudden oil starvation, severe engine seizure, or total power loss without warning while driving at highway speeds, increasing the risk of a crash. Furthermore, dripping oil contacting hot exhaust or engine components presents a potential fire hazard. Prior Symptoms / History: This vehicle has a well-documented history of severe internal engine issues and thermal stress, including excessive oil consumption (running 1.2 quarts low in 1,127 miles), valve cover gasket failure, and severe drivetrain vibrations from failing front axles. The excessive internal crankcase pressure and thermal stress from these underlying defects contributed directly to the material fatigue and structural failure of this aluminum oil pan.

I purchased my vehical at Car Culture in Warren, Oh. The dealer said to only take it there for maintenance, so I did as required. Whenever the check engine light came on I would bring it there and they would say it was a sensor and they fixed it. And one day it started miss firing and the light came on again. When I took it to the dealership, they said it needed oil to bring it in every 2 weeks to top the oil off. And so I did that and finally the car was getting worse at 122,000 miles. When I took it there they said it needed a new motor!!!. They NEVER told me of a recall or a sensor replacement needing done by hyundai. Iam now stuck with a $13,000 loan on a car worth nothing without paying $5,000 on a "possible" fix for their negligence. I have a [XXX] old son, fiancee, morgage and a job im struggling to get to, because I was never notified of a possible recall on my year, make and model of car. Please help me. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

We think there’s an issue with the abs module and wheel speed sensor because we started having a problem where the brakes wouldn’t work or would stutter. The car would shake real bad it would make an awful grinding sound but normally only when trying to stop at higher speeds or long braking. The only thing that made it stop was to unplug the abs but then other parts of the car stopped working like the speedometer and the sensors around the car. So we got the abs replaced but the new one started doing the same thing. We did some research and it sounds like the same issue Hyundai is having with the palisade. The incident that made us get it replaced to begin with was were driving down the road and we got to a traffic light but when we tried to brake they just didn’t work so we drove through the red light luckily the one person who was supposed to be going saw us and didn’t pull out in front of us so we didn’t get hit. We haven’t taken it to the dealership yet but my sister who teaches automotive repair at the community college is the one who diagnosed it so she said we should report it here so maybe it won’t happen to anyone else. Before we had the brake issue we were having problems with basically everything on the dash not working randomly. We’d be driving down the road and the speedometer and the outside sensors and the gas gauge and the traction control all would go out at the same time it’s the same stuff that went out when we had the abs unplugged so it seems that might be related.

The vehicle had safety and mechanical problems shortly after purchase, even with low mileage. The issues included warning lights, abnormal noises, repeated mechanical failures, and poor performance that affected the safe operation of the vehicle. These problems started early and continued over time despite repairs and maintenance. Before the incident, the vehicle showed signs of malfunction, including instability while driving and loss of normal performance. These symptoms created an unsafe driving condition and increased the risk of a crash. I believe the vehicle had defects from the beginning that affected safety. The failure contributed to the accident that occurred while driving on the highway, putting my life and my family at risk.

Check engine light solid/engine failure while driving. 2018 Sonata SE purchased new in fall 2018. Around 50,000 miles started noticing oil level drop and had to add more before next scheduled change. Dealership service center said I just had to shorten the mileage between changes which didn't seem appropriate for a vehicle with 50,000 miles but I did. Continued to have oil consumption problem with no signs of leak, no burning oil smell or exhaust issues. Dashboard display would go off and when I immediately checked dipstick there was barely any oil so I'd add more then go in for full change. At 67,000 or so miles in June 2026, without oil display going off the engine light was now solid. Got to reputable service center near my home and oil was under a quart left yet the warning lamp hadn't gone off. They ran the engine error code P0304 and was misfire #4 cylinder and after compression test, #3 was very low and #4 very high. NOT drivable at that point then towed to dealership so yes, available for inspection by NHTSA at the dealership. For now they claim a 'tune up' is needed for spark plug replacement, valve cover gasket replace and fuel induction service that's my cost to incur which seems to just be fixing the damage of an engine oil consumption problem not fixing the issue that caused the damage. The engine seized/stalled without warning while I was driving the vehicle (granted at low speed in my neighborhood when the engine light turned on). I would not say the engine warning lamp occurred prior to the engine fail, it happed at the same time. This should not happen for a vehicle with my mileage and regular maintenance. I looked up NHTSA for potential recall or other helpful information and started to see extremely similar scenarios to mine and wanted to add complaint as well. This is getting very expensive outside of whatever cost the dealer wants as a fix with rental car needed and tow services. Thank you for your consideration of this engine safety issue.

Following completion of Service Campaign 9C2 (ECU software update, TSB 25-01-087H) at a Hyundai dealership, my 2018 Sonata immediately exhibited drivability changes that were not present before the service. Symptoms include altered shift timing, hesitation, and rougher throttle response — particularly noticeable during the first several minutes of driving. These symptoms began on the first drive after the recall update was applied and have been consistent since. The vehicle was returned to the dealership for inspection. No underlying mechanical issue was found, confirming the drivability change is directly attributable to the ECU software update. The vehicle has been maintained strictly per Hyundai's manufacturer-recommended schedule and had no prior drivability issues. I am aware that numerous other owners of Theta II-equipped vehicles (Sonata, Santa Fe, Tucson) have reported identical symptoms following 9C2. At least one dealership has reportedly acknowledged this as a known post-update issue that Hyundai is working to resolve. The altered throttle and shift behavior poses a safety concern, as unexpected hesitation during acceleration affects predictable vehicle control in traffic. The vehicle is available for inspection upon request.

The contact owns a 2018 Hyundai Sonata. The contact stated that while operating the vehicle, there was an abnormal fuel odor inside the vehicle. The vehicle was taken to the local dealer and was diagnosed with an inoperable low-pressure fuel pump. The contact was informed that the low-pressure fuel pump needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure. The contact stated that the manufacturer had issued an extended warranty coverage for the failure. The failure mileage was 92,000.

Fuel line leak, car is parked, fire hazard, a mechanic has been there to inspect

About a year and half ago, a lot of my engine trouble lights turned on while driving. It was sleeting at that time when the lights turned on and they're still on today. I paid to have the Hyundai dealer to check it out soon after the trouble lights first turned on. They diagnosed the problem as a faulty HECU. I would have had them replace this, but they estimated it would cost about $3800 to fix. This HECU malfunction is causing the following issues: ABS does not work, traction control does not work, forward collision prevention does not work, brake auto hold does not work, cruise control does not work probably because it can't auto brake any more. I've had some scary times driving and trying to stop when the roads have been wet or snowy.

When starting car warning lights came on for ABS, AEB, Cruise Control. Cruise control is locked out and not working due to these warnings.

THE HEADLIGHT LOW BEAMS ARE DANGEROUS AND NEED TO BE RECALLED ASAP? After his death, I acquired this vehicle from my father who had stopped driving at night thinking he had developed a vision issue. The first time I drove it at night I discovered the low beams are defective, and that was the problem, not my dear old Dad’s vision. The light emitted does not extend far enough in front of the vehicle to light a large enough safe distance. There are also large black areas at the far edge of each light that float from side to side with the beam while making turns. This also causes the areas on one side or the other to loose lighting. While turning they are often facing the wrong direction making it virtually impossible to see the unlit areas. We live in the country down a 20 mile long two lane road with many turns and minimal lighting compared to city driving. We then turn onto a 3 mile very narrow road with numerous turn, minimal shoulders, and a double hairpin turn with a dip at the end. It required us to leave the high beams on at all times even when other vehicles are approaching because it would be too dangerous to only use the low beams. When I took it to the dealer they ignored the problem. I then insisted they examine them immediately—since that was my #1 PRIORITY when I dropped it off for inspection during a regular service. Their conclusion was that there was nothing they could do to fix it. THAT IS AN UNACCEPTABLE RESPONSE! THOSE LOW BEAM LIGHTS ARE EXTREMELY DANGEROUS. My research has found that this has been an issue since the vehicle was first made and when purchased by my dear old Dad, his only way of dealing with it was to stop driving at night.

Back up lights. The lights constantly burn out causing the harness light holder to burn out. The lights will not come on even after replacing fuse and lights There are not back lights to warn patrons on the road for turning or stopping Yes it was taken to a dealership No it has not been inspected my either , but there is a recall on models of the same car but years 2011-2014 No there were no warnings , someone told me they were out

We think there’s an issue with the abs module and wheel speed sensor because we started having a problem where the brakes wouldn’t work or would stutter. The car would shake real bad it would make an awful grinding sound but normally only when trying to stop at higher speeds or long braking. The only thing that made it stop was to unplug the abs but then other parts of the car stopped working like the speedometer and the sensors around the car. So we got the abs replaced but the new one started doing the same thing. We did some research and it sounds like the same issue Hyundai is having with the palisade. The incident that made us get it replaced to begin with was were driving down the road and we got to a traffic light but when we tried to brake they just didn’t work so we drove through the red light luckily the one person who was supposed to be going saw us and didn’t pull out in front of us so we didn’t get hit. We haven’t taken it to the dealership yet but my sister who teaches automotive repair at the community college is the one who diagnosed it so she said we should report it here so maybe it won’t happen to anyone else. Before we had the brake issue we were having problems with basically everything on the dash not working randomly. We’d be driving down the road and the speedometer and the outside sensors and the gas gauge and the traction control all would go out at the same time it’s the same stuff that went out when we had the abs unplugged so it seems that might be related.

About a year and half ago, a lot of my engine trouble lights turned on while driving. It was sleeting at that time when the lights turned on and they're still on today. I paid to have the Hyundai dealer to check it out soon after the trouble lights first turned on. They diagnosed the problem as a faulty HECU. I would have had them replace this, but they estimated it would cost about $3800 to fix. This HECU malfunction is causing the following issues: ABS does not work, traction control does not work, forward collision prevention does not work, brake auto hold does not work, cruise control does not work probably because it can't auto brake any more. I've had some scary times driving and trying to stop when the roads have been wet or snowy.

The trunk latch on the Hyundai Sonata malfunctioned, and our safety was put at risk when the trunk malfunctioned while driving on the freeway, obstructing the back view. After several attempts to try to close the trunk and after doing some research, I learned it had a vehicle recall, 21V619000. An appointment was made at Ontario Hyundai for the latch to be repaired due to the recall. After taking the vehicle in, the dealer stated that an attempt to repair the latch had been attempted and refused to do the repair and provided an invoice of $616.00 for repair. Since the latch malfunctioned, no attempt to repair the latch was ever attempted, nor was it taken anywhere else for repair. The vehicle is available for inspection upon request. The trunk latch is still inoperable, and recall status is incomplete.

The paint has been chipping from the hood and top.

See attached document for complaint. Please let me know how quickly the service parts for these two recalls are physically located in your shop and how soon the required recalls will be performed. I have been getting periodic recall notices for years and have yet to obtain the satisfaction of an adequate local response from your service department. I can recall three instances when I was told the parts were ready, only to leam, upon arrival, they were not. The last incident was on May 27"', when I was told the parts were ready and I could have the recall performed on May 30'". Another huge disappointment occurred when I was told the parts were not available. That is not the way to run a governmental required recall program.

The contact owns a 2018 Hyundai Sonata. The contact stated the trunk failed to open while using the key fob and the controllers on the interior of the vehicle. The contact had taken the vehicle to the dealer where it was diagnosed that the trunk latch had failed, and the emergency cable associated with the trunk needed to be replaced. The vehicle had not been repaired. The manufacturer was made aware of the failure and a case was opened. The failure mileage was 44,176.

During multiple dealership visits in 2025, my 2018 Hyundai Sonata Limited 2.0T was repeatedly returned in unsafe condition. Southern Hyundai installed both front CV axles and torqued them incorrectly. The right axle was later confirmed under-torqued by about 50 ft-lbs, and the left axle was later found over-torqued 40ft-lbs Priority Hyundai later identified and corrected the under-torqued right axle, which briefly improved symptoms but did not resolve the underlying issue. When I returned for a follow-up on October 29, 2025, for a documentation-only appointment due to an active corporate case, the dealer ignored my instructions and altered evidence by loosening and re-torquing the left axle nut without consent. They recorded the torque at 250 ft-lbs in the repair order but failed to capture the required photos or before/after readings and referenced the wrong vehicle’s torque specification (Hyundai Elantra) in the documentation. Since then, the vehicle has continued to show steering pull, vibration, and instability at speed. Several visits showed only 0–3 miles of verification driving after safety-critical repairs involving brakes, suspension, and driveline components. Aftermarket parts were installed when OEM parts were promised, and uneven tire wear developed quickly. Safety risks include wheel-bearing damage, steering loss, and driveline separation due to repeated improper torque and altered evidence. Independent Firestone and Honda technicians have verified these issues. The matter remains under active Hyundai Corporate Case #[XXX]. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

On 05/27/2025, my rear back-up camera started to malfunction. Last week my dash started to malfunction electronically. When I would start my vehicle, all of the lights would start to turn on and stay on on my dash. My speedometer would not move while I was driving, so I could not see how fast I was going. I believe this is a severe safety issue for myself as well as others. The tachometer would jump up and down and would not function correctly. My dash stated that I had low tire pressure, that I was having problems with my traction control, that my BSD system was not working, that my ABS was not working, that my emergency brake was on even though it was not. It also stated that I did have functioning air bags, which is a severe safety hazard in the chance that I could've gotten into a wreck and they might not have worked. It also stated that I was not in Drive even though I clearly was. It also stated that I had no power steering while I was driving, before the light would turn off and I could properly steer again. This is a severe safety issue that could put me at risk. Finally, my check engine light turned on and stayed on. Yesterday on 06/09/2025 I was able to take it a vehicle maintenance shop so they could run a full diagnostic test. They discovered that I did not have power steering even though there was fluid due to the electrical problems with my dash. They also discovered the C-CAN buss was off and that my vehicle was losing communications with the TCM and HVAC. It was discovered that this was due to my rear view back-up camera malfunctioning, causing the C-CAN network to short out. They had to unplug my rear back-up camera to return everything to normal. I have found on hyundai recall forms that other years of hyundai models had similar problems and I believe that 2018 hyundai sonatas are also having the same problem. I wanted it to be made aware because online, people have stated they are having the same issues. Attached gif that shows part of problem.

The contact owns a 2018 Hyundai Sonata. The contact stated that upon entering the vehicle, the contact became aware that the driver’s side seat belt failed to latch securely into the buckle. The seat belt warning light was illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the seat belt buckle. The vehicle was not repaired. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was 45,000.

The contact owns a 2018 Hyundai Sonata. The contact stated while driving 70 MPH, the check engine warning light illuminated, and the vehicle lost motive power. The vehicle was taken to the dealer where the dealer performed a compression check. The failure reoccurred. The vehicle was taken back to the dealer and the contact was advised to drive the vehicle until it blew up. In addition, the contact stated that all four seat belts had failed to function as intended. The contact stated that the front driver's side and passenger's side seat belts failed to retract as intended. The contact stated that the seat belts failed to secure the passengers in place. Additionally, the contact stated that the rear seat belts completely failed to retract as needed. The vehicle was not diagnosed or repaired by the independent mechanic or the dealer. The manufacturer was made aware of the failure but provided no assistance. The contact was advised to take the vehicle to the dealer for a combustion check and an oil consumption test to be performed out-of-pocket expense. The failure mileage was approximately 100,000.

The contact owns a 2013 Hyundai Sonata. The contact stated that all the rear row seat belts did not buckle as intended and water would leak from the front passenger side air conditioner. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 125,000.

PASSENGER SIDE WINDSHIELD WIPER WORKS WHEN IT WANT TO WORK.

During multiple dealership visits in 2025, my 2018 Hyundai Sonata Limited 2.0T was repeatedly returned in unsafe condition. Southern Hyundai installed both front CV axles and torqued them incorrectly. The right axle was later confirmed under-torqued by about 50 ft-lbs, and the left axle was later found over-torqued 40ft-lbs Priority Hyundai later identified and corrected the under-torqued right axle, which briefly improved symptoms but did not resolve the underlying issue. When I returned for a follow-up on October 29, 2025, for a documentation-only appointment due to an active corporate case, the dealer ignored my instructions and altered evidence by loosening and re-torquing the left axle nut without consent. They recorded the torque at 250 ft-lbs in the repair order but failed to capture the required photos or before/after readings and referenced the wrong vehicle’s torque specification (Hyundai Elantra) in the documentation. Since then, the vehicle has continued to show steering pull, vibration, and instability at speed. Several visits showed only 0–3 miles of verification driving after safety-critical repairs involving brakes, suspension, and driveline components. Aftermarket parts were installed when OEM parts were promised, and uneven tire wear developed quickly. Safety risks include wheel-bearing damage, steering loss, and driveline separation due to repeated improper torque and altered evidence. Independent Firestone and Honda technicians have verified these issues. The matter remains under active Hyundai Corporate Case #[XXX]. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2018 Hyundai Sonata. The contact stated while driving at an undisclosed speed, the vehicle lost motive power. The check engine warning light was illuminated. Additionally, engine oil was leaking onto the ground while the vehicle was parked. The contact stated that the dealer had previously replaced the spark plugs, and cylinders #3 and #4 twice, and an independent mechanic had replaced the front driver's side CV axle. The vehicle was towed back to the dealer, who determined that the engine had internal defects. The contact was informed that the engine and front CV axles needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but refused to replace the engine. The failure mileage was approximately 86,800.

the Kumho 205/65 R16 treads are losing chucks of rubber on 3 tires with just under 17000 miles as of this date 7/24/23 and under 6 years old. ( their warranty states 60K or 6 yrs) Kumho will not warrant the tires in any way shape or form. Have tried to get some help from them since Jan of this year (2023) with no results. Also the service dept at the dealership tried to get me help but was not successful. Even after taking many pictures and information and sending them to Kumho. No help.

The contact owns a 2018 Hyundai Sonata equipped with Hankook Tires, Tire Line: Kinergy ST, Tire Size: 205/65/R16, DOT Number: (N/A). The contact stated that three of the four tires had failed. While the vehicle was in for a Vehicle State Inspection, it was discovered that the rear passenger’s side tire was deformed and wobbly which cause the vehicle to fail the inspection. Additionally, while driving approximately 70 MPH, the vehicle started shaking violently. The contact pulled over to the side of the road and stopped the vehicle. Upon inspection, it was discovered that the rear driver’s side tire had experienced a blowout. Additionally, the third tire was discovered to be deformed. The cause of the failure was not determined. The tire dealer and manufacturer were notified of the failure. The failure mileage was 28,000.

The three airbags in the car (on the driver's weel, driver's knee, and the passenger's side) deployed while driving on a normal street at a speed of 50 miles/hour. This is an unexpected behavior of a car at a normal speed. I need help to fix this car and know what is the reason this happened.

I am Detective [XXX] #XXX with Austin Police Department Vehicular Homicide Unit and I worked a fatal crash [XXX]. The damage to the vehicle two vehicle should not have caused a death. The airbag became detached from the steering wheel and impaled into the drivers chest. I do have pictures but they are crime scene pictures and pictures of the decedent so I am not attaching them but if someone contacts me I can arrange that. I do not know the speed but I am going to image the module next week. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owned a 2018 Hyundai Sonata. The contact stated that while driving, the vehicle caught fire without warning. No warning lights illuminated. The air bags did not deploy. The fire department was notified and was able to extinguish the fire. The origin of the fire was unknown. The contact sustained a burn to her inner left ankle. Medical attention was required. A police report was filed. The vehicle was towed to a tow yard. The dealer was notified of the failure, but no assistance was provided. The vehicle was not diagnosed or repaired. The vehicle was deemed totaled by the insurance. The manufacturer was not notified of the failure. The failure mileage was approximately 112,000.