2018 Hyundai Sonata Problems And Top Complaints – Is Your Car A Lemon?

Speed control, headlights, electrical, brakes and engine issues among the top complaints received by the NHTSA from vehicle owners

When it comes to finding a low-cost midsize car, consumers have been fond of the 2018 Hyundai Sonata. The newer models seem to have plenty of technology, provide a great value and high-reliability ratings. Even the automaker claims that these cars will help owners “conquer your commute.” Still, it’s hard to figure out where the popularity and accolades come from considering this model seems to have numerous issues with the electrical system, brakes, engine and more.

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Problems with the Electrical System

What does the electrical system run in a vehicle? It might be easier to ask, what doesn’t it run? This system is the nervous system of any vehicle and must operate correctly for a smooth, comfortable drive. Yet, owners continue to take to the internet and express their dissatisfaction.

One NHTSA complaint says, “On 3/23/19, when I was leaving a parking lot. My car started to hesitate and would not rev up. I just turned out the parking lot when this happened. Message came on stated it need to be serviced. At the same time the engine light came on. I was not able to press the accelerator because it would jump like crazy. I was able to get back to the parking lot safely. I have been in a rental for a month now and as of 4/23/2019 I was told the part is on back order. The wiring harness and the computer has to be replaced, but the tech stated since the car went into limp mode, the engine will need to be replaced. I was told the part will be in about 3 to 6 months. If the wiring harness does not work God only know how many more months it will take for a new engine to arrive. This car was only 9 months old but now 10 months old with one of the months being in the shop waiting for repairs.”

Why in the world would it take so long to get the necessary parts to fix a new car? It seems the automaker is struggling with numerous electrical problems and is currently under investigation with the NHTSA. Action Number EA19001 shows an ongoing look into the airbags on this vehicle. It seems there has been a failure within the ACU, which tells the airbags to deploy. It’s unclear what the outcome will be, but it doesn’t take a rocket scientist to see this isn’t a car anyone should be commuting with.

Here are some actual complaints logged with the NHTSA about the 2018 Hyundai Sonata Electrical Problems:

CAR HAS KEYLESS START. WILL NOT START IN TEMPS BELOW 20 DEGREES F. HAS HAPPENED 4X IN 2 WEEKS. CAR IS 8 MOS OLD / LESS THAN 6K MILES. 1ST 3 TIMES EVENTUALLY STARTED BY RUNNING ENGINE. THE WARNING LIGHTS THAT SHOW ARE CHARGING SYSTEM (RAN ITSELF DOWN TO 57% BATTERY THIS TIME); ENGINE OIL PRESSURE AND MIL LIGHT. THE IMMOBILIZED INDICATOR IS ON BUT THEN GOES OFF. THE TANK IS FULL OF GAS. THE BLUE LINK APP CAN’T REMOTELY START THE CAR. IT STATES THAT THE REQUEST WAS NOT PROCESSED.

Problems with the Engine

As with the last complaint, it’s easy to find a long list of engine troubles coming from this car.

Here is yet another review left on Edmunds. “I purchased this car brand new in August 2018. In March 2019, I received a recall notice saying I needed to visit my dealer to have the computer for the car’s engine updated. I took the car to the dealer 3 days later. Five days after that, I’m driving to NY and 400+ miles away from home, my brand new car begins “limping” as I try merge onto a busy bridge. I took the car to the nearest dealer in Staten Island, NY and it is still there today. Not sure what is wrong. I understand this is a huge problem for the company where the engine or the harness in the Sonata and Santa Fe models need replacing. They think it’s the harness, however, the piece has yet to arrive, so no telling. Because my trip was considered interrupted, I called Hyundai’s Customer Care 800 and received directions on what I should do next.”

With Service Bulletin #19-EE-007H(1), it’s evident that this isn’t the only engine trouble Hyundai is dealing with. It appears some of the engines also have a starter M-Terminal nut that comes loosened easily. This creates a no-start situation, especially in cold temperatures. How is it that this car left the production line with a nut that doesn’t stay secure? Who is this automaker employing that doesn’t know how to tighten nuts properly? Maybe that’s how they keep the cost down, but neglecting the basics.

Here are some actual complaints logged with the NHTSA about the 2018 Hyundai Sonata Engine Problems:

TL* THE CONTACT OWNS A 2018 HYUNDAI SONATA. WHEN THE VEHICLE WAS STARTED, IT SPUTTERED AND FAILED TO ACCELERATE OVER 30 MPH. ALSO, THE CHECK ENGINE WARNING INDICATOR ILLUMINATED. THE VEHICLE WAS TOWED TO TITUS-WILL HYUNDAI WHERE IT WAS DIAGNOSED THAT THE ENGINE AND WIRING HARNESS NEEDED TO BE REPLACED; HOWEVER, THE PARTS WERE ON BACKORDER. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS CONTACTED AND PROVIDED CASE NUMBER. NO FURTHER ASSISTANCE WAS PROVIDED. THE FAILURE MILEAGE WAS 22,000.

I TOOK MY 2018 HYUNDAI SONATA SE IN FOR ITS FIRST OIL CHANGE WITH 3564 MILES ON IT. THEY DID A COMPUTER UPDATE AS PART OF A RECALL. I DROVE LESS THAN ( MILES FROM THE DEALERSHIP, WENT TO PULL OUT FROM A STOP LIGHT. IT STARTED MISS FIRING AND THE CHECK ENGINE LIGHT STARTED FLASHING. I WENT BACK TO THE DEALER. THEY SAID IT HAD A CODE AND TGEY HAD TO CALL HYUNDAI TO FIND OUT WHAT TO DO. THEY GAVE ME A LONER AND TOLD ME THE WIRING HARNESS HAD TOO MUCH INTERFERENCE/STATIC IN IT AND THEY HAD TO ORDER A NEW ONE. VERY HARD TO BELIEVE A COMPUTER UPDATE WOULD CAUSE THE WIRING HARNESS TO GO BAD.

CHECK ENGINE LIGHT CAME ON;ENGINE ERROR CODE 1326. CAR BEGAN STALLING. GOT IT TO DEALER WHO KNEW IT WOULD NEED A NEW WIRING HARNESS POSSIBLY A NEW ENGINE. THIS IS DANGEROUS WILL GET SOMEONE KILLED. THIS HAPPENED RIGHT AFTER EXITING THE HIGHWAY PULLING ONTO THE SERVICE ROAD.

Problems with the Exterior Lighting

While discussing the basics, it’s time to look at the exterior lighting. This is one system that doesn’t regularly receive many complaints from drivers of new vehicles unless we are discussing the Sonata.

One NHTSA complaint illustrates a significant problem. It says, “Defective headlights. A black projection protrudes down the middle of each headlight in the line of sight. Very, very distracting. Must use hi-beams at all times to eliminate the sight hazard, which then can become a danger to oncoming vehicles. Hyundai says, ‘Sorry about that, nothing we can do.’ They should at least be required to offer a replacement headlight, which would eliminate this hazard.”

In Service Bulletin #5NP-A4C8N-03, Hyundai addresses this concern, but not in the way many people would expect. Instead, they claim that the black section is designed to stop the oncoming light glare and will not be replaced. It doesn’t matter that the drivers of their vehicles don’t appreciate this technology. That’s not what they are concerned with at all. It looks like this car helps to conquer the commute unless it is nighttime.

Here are some actual complaints logged with the NHTSA about the 2018 Hyundai Sonata Defective Headlights Problems:

THE LOW BEAM HEADLIGHTS ARE USELESS CAN’T SEE 30 FEET IN FRONT OF VEHICLE WHEN TURNING CAN’T SEE ANYTHING OR LIMITED IN FRONT OF YOU. HAVE TO DRIVE WITH HIGH BEAMS ON IN ORDER TO SEE. DEALER SAYS HEADLIGHTS ADJUSTED CORRECTLY. THERE IS DEFINITELY A PROBLEM. THE VEHICLE IS NOT SAFE TO DRIVE AT NIGHT CAUSING THIS TO BE A DANGER TO DRIVERS AND PEDESTRIANS. WHEN TURNING IT’S IMPOSSIBLE TO SEE IN ORDER TO MAKE SAFE TURN.

FROM THE TIME OF PURCHASE IN JUNE 2018, THE LOW BEAM HEADLIGHTS ARE AIMED VERY LOW AND PROJECT ONLY 15 TO 20 FEET IN FRONT OF THE CAR. WHEN TRAVELING ON DARK ROADS, IT ALLOWS FOR NO REACTION TIME TO ANY HAZARDS, SUCH AS ANIMALS OUR PEDESTRIANS. HYUNDAI CLAIMS IT IS DESIGNED TO NOT BLIND ONCOMING DRIVERS, BUT THIS POSES A DANGER TO THE OCCUPANTS OF MY CAR AND ANYONE THAT MAY BE NEAR THE CAR.

THE PROJECTED ANGLE OF THE HEADLIGHTS DO NOT PROJECT OUT FAR ENOUGH WHEN DRIVING THIS VEHICLE. THE HEADLIGHTS ONLY PROJECT OUT ONE VEHICLE IN FRONT OF THE DRIVER, LEAVING A VAST AMOUNT OF DARKNESS IN FRONT OF THE DRIVER IN THE HYUNDAI SONATA. THIS IS A SAFETY HAZARD FOR THE OWNER OF THIS VEHICLE.

Problems with the Vehicle Speed Control

Modern vehicles continue to use new technology to provide a safer ride, but what happens when the ride becomes downright dangerous? That’s what is evident with the Sonata.

Just look at this NHTSA complaint. “The contact owned a 2018 Hyundai Sonata. While the vehicle was stopped at a traffic light, the accelerator pedal was depressed; however, the vehicle failed to respond. On a second occasion, while exiting the driveway, the accelerator pedal was depressed to the floorboard, but the vehicle failed to exceed 2 mph. In addition, the check engine and tire pressure monitoring system warning indicators illuminated. The vehicle was taken to [dealer] where it was diagnosed that the fail had gone into limp or fail safe mode. The contact was also informed that an unknown cable was loose. The vehicle was not repaired. The manufacturer was notified. The contact traded in the vehicle. The approximate mileage was 4,000.”

How sad that this owner had to trade in the vehicle for a new one, probably at a depreciated value? Interestingly enough, the automaker isn’t attempting to hide any trouble with the vehicle speed control. Service Bulletin #5NP-X7G2S-09 talks about trouble with shift shock and deceleration that requires an update to the TCU. If this car was made for commutes, it seems many people are having trouble getting to work on time.

Here are some actual complaints logged with the NHTSA about the 2018 Hyundai Sonata Speed Control Problems:

THE CONTACT OWNED A 2018 HYUNDAI SONATA. WHILE DRIVING APPROXIMATELY 5 MPH, THE VEHICLE INDEPENDENTLY ACCELERATED. THE CONTACT DEPRESSED THE BRAKE PEDAL, BUT IT FAILED TO SLOW DOWN OR STOP THE VEHICLE. THE VEHICLE CRASHED INTO A PALM TREE. AN INCIDENT REPORT WAS FILED, BUT NOT A POLICE REPORT DUE TO THE FACT THAT THERE WAS NO IMMEDIATE INJURY. THE CONTACT SUFFERED A SORE NECK AND A POSSIBLE WHIPLASH. THE VEHICLE WAS TOWED TO AN INDEPENDENT FACILITY. KEARNEY MESA HYUNDAI WAS CONTACTED AND A VOICE MESSAGE WAS LEFT. THE MANUFACTURER WAS NOT CONTACTED. THE CAUSE OF THE FAILURE WAS NOT DETERMINED. THE APPROXIMATE FAILURE MILEAGE WAS 500.

TL* THE CONTACT OWNS A 2018 HYUNDAI SONATA. WHILE DRIVING AT LOW SPEEDS, THE VEHICLE UNINTENTIONALLY ACCELERATED AND CRASHED INTO A POLE. THE AIR BAGS DEPLOYED. A POLICE REPORT WAS FILED AND THERE WERE NO INJURIES. THE VEHICLE WAS TOWED TO CARBONE HONDA BENNINGTON BUT WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOT NOTIFIED OF THE FAILURE. THE FAILURE MILEAGE WAS APPROXIMATELY 8,800. 

Problems with the Brakes

Finally, it’s time to look at the brakes on the Sonata. Once again, we see this is just a malfunctioning system that can’t get its act together.

This NHTSA complaint states, “Since day of deliver two years ago, the AEB system has malfunctioned in that while driving vehicle on any road type, the brakes come on with no warning or reason, have almost been rear ended three times. Dealer has never found anything wrong and insists the system functions as designed. The radar or camera systems have to have a defect. Toyota and Honda have had this issue but made efforts to correct either by recalls or service bulletins. Pedestrian detection has also never worked on this vehicle.”

While this driver is correct, there is no service bulletin to reference in this instance; it’s clear that the automaker is hiding something. In the meantime, it might be best to stay far away from the Sonata as a pedestrian walking to work, unless you want to test out the system for the owner.

Here are some actual complaints logged with the NHTSA about the 2018 Hyundai Sonata Brake Problems:

TL* THE CONTACT OWNS A 2018 HYUNDAI SONATA. WHILE OPERATING THE VEHICLE, THE AUTOMATIC EMERGENCY BRAKING SYSTEM MALFUNCTIONED. ON SEVERAL OCCASIONS, THE VEHICLE FAILED TO AUTOMATICALLY STOP WHEN A SECOND VEHICLE WAS PRESENT. THE FAILURE OCCURRED WHILE DRIVING IN REVERSE AND WHILE DRIVING AT HIGHWAY SPEEDS WITH THE CRUISE CONTROL ACTIVATED. THE VEHICLE WAS TAKEN TO NAPLETON HYUNDAI GLENVIEW (1620 WAUKEGAN RD., GLENVIEW, IL) AND THE CONTACT WAS INFORMED THAT THE FAILURE WAS NORMAL. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE, BUT NO ASSISTANCE WAS OFFERED. THE FAILURE MILEAGE WAS 400.

I HAD STOPPED MY VEHICLE, PUTTING EMERGENCY BRAKE ON, BUT STILL IN DRIVE. I STEPPED OUT OF THE CAR AND IT BEGAN TO MOVE FORWARD ON ITS OWN AND I WAS NOT ABLE TO GET BACK INTO THE VEHICLE. IT TRAVELED QUITE A DISTANCE BEFORE RUNNING INTO SOME INANIMATE THAT CAUSED IT TO STOP. IT WAS IN A DRIVEWAY BEHINDS BUILDINGS AND DID EVENTUALLY CROSS OVER A SIDE STREET BEFORE STOPPING. I DON’T SEE WHY THE EMERGENCY BRAKE DID NOT HOLD, EVEN THOUGH NOT IN PARK?

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