pretty bad
Typical Repair Cost:
No data
Average Mileage:
11,550 miles
Total Complaints:
10 complaints

Most Common Solutions:

  1. not sure (5 reports)
  2. replace wire harness (5 reports)
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2018 Hyundai Sonata engine problems

engine problem

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2018 Hyundai Sonata Owner Comments

problem #10

Dec 302019

Sonata SE 2.4L

  • Automatic transmission
  • 26,649 miles


Hyundai sent a notice to me to update software to the ECU at no cost and this update would add a layer of protection against engine failure. Well since I took advantage of this, my car has put me in 2 dangerous situations of losing power suddenly. 1st incident the engine light started flashing and wouldn't go faster than 40mph. I drove it straight to the dealership and they had it for 4 days and replaced a wire harness-knock sensor. Its less than 2 mos. later & I get stranded, this time on a dark 2 way road. The engine light suddenly turned on & car wont go faster than 9mph. I pulled to the side & at this time the car completely dies with no start-up. Dash says "Multiple possible conditions have occurred with your vehicle. A full system check is recommended soon, To schedule an appointment with a dealer press the BLUELINK or SERVICE LINK button on your screen.

I feel this may all be a gimmick to get your car in for extra services not needed just like this update. After about 10mins later it was able to start but there again with no power at 9pmh. Being that I'm creating tons of traffic during commute time (this was a one lane road and not feeling good about driving the car I pull over to call a tow truck that cost me extra money because my insurance only covered up to $100. My thoughts is I believe this software update ruined the car and I feel my car is not safe because it stops so suddenly it can easily create an car to hit you from the back . The car is at the dealership now and I don't know what's wrong w/it but honestly if they fix it I'm still scared to drive and trust it.

- Dana H., Antioch, US

problem #9

Jun 142019

Sonata 2.0T 2.0L

  • Automatic transmission
  • 21,000 miles

click to see larger images

check engine light on

On June 14, 2019, I noticed that my 2018 Sonata 2.0T was idling rough and the RPM needle would jump when at a standstill. I could also hear what sounded like faint backfiring coming from the exhaust (similar to a possible vacuum leak). Prior to this, and shortly after purchasing the car in October 2017, I had several instances of the engine making an audible (and physical) clunking noise when starting. I recorded video of the June 14 incident and was making plans to contact Hyundai the following Monday.

On the evening of June 14 and following the earlier incident, my check engine light illuminated and a message appeared on my display that a condition with my engine control system has been detected and should be seen immediately. I contacted my local Hyundai service department and was informed to have the car towed to the dealership for diagnosis.

Based on all of the similar symptoms noted in other complaints, I'm fairly certain this is a likely issue with the engine wiring harness. I have not heard back from the service department, but my fear is that they will only complete an update for the knock sensor detection system without addressing possible damage that has already occurred to the engine. I will update this post as soon as I know more.

Update from Jun 17, 2019: Auffenberg Hyundai determined the cause to be 2 spark plugs that were missing the porcelain. They will be replacing them, but also indicated that 2 other plugs look bad, but have not thrown a code that would trigger replacement. They also completed the knock sensor detection system update.

- aswiercz, Belleville, US

problem #8

May 122019

Sonata SEL 2.4L

  • Automatic transmission
  • 22,243 miles

I am a Uber driver and almost got into a bad accident because of this problem. I had passengers in the back seat and was going through a busy intersection when I was reduced to a slow crawl. Luckily other drivers saw a problem and stopped before slamming into me. Had the car towed to the dealer.

- Michael Z., Reading, PA, US

problem #7

Mar 092019

Sonata Sport 2.4L Gdi

  • Automatic transmission
  • 7,400 miles


My wife and I bought the 2018 Sonata Sport in October 2018. It was a birthday present for my wife and she wanted a cool car to drive. I took the vehicle in to the dealership for its FIRST service on March 2, 2019. They rotated the tires, changed the oil and performed this "software update". Went on with our lives as normal.

Everything was going great until Saturday evening March 9, 2019. We were on our way back to Columbus, Ohio from Dayton after a soccer tournament. My wife was driving down I70 in a blinding rainstorm, when all of a sudden the engine light started flashing, the engine started sputtering and the computer screen said "Engine System Malfunction". We couldn't manage more than 50mph down a busy interstate as cars and semis flew past us. We made it the 30 miles home and then I took it in to the dealership on Monday March 11th.

Initially, we thought the engine needed replaced but then the dealership said that it was merely a wiring harness that needed to be replaced. What a relief! How hard could that be?! WELL, let me tell you. The car has been sitting at the dealership waiting on this part for 37 days and counting with no end in sight! I was told the wiring harness was placed on "national back order" and to just sit tight! Sit tight?! Now I am paying for a car that we can't drive, paying for XM that we can't listen to, and my family has to ride around in a Hyundai Elantra as our family car. It's a lot of things, but it's not a family car!

I've been talking to Hyundai Corporate through the process, especially now because my car is officially a lemon under Ohio law. Hyundai was supposed to elevate my case to the repurchasing group to talk about them giving me a refund for the car, but after a week they've gone MIA. I can't get a hold of anyone to talk to me. So now I sit, waiting and waiting and waiting. How this massive issue has not gotten the media attention it deserves is beyond me! Hyundai screwed the pooch with this software update an no one is talking about it other than on message boards.

I really wish we would've bought the Honda CRV that we originally planned! Ok, rant over for now!

- Tyler B., Groveport, US

problem #6

Apr 212019

Sonata Sport 2.4L

  • Automatic transmission
  • 12,000 miles

Had the recall software fix performed. After that, my daughter was driving the car and the engine light came on and went into limp mode. Very dangerous given crazy fast LA traffic. Car is now at dealer and likely will be for 3-4 weeks given a parts shortage reported by the dealer. This problem cannot be ignored by Hyundai since its becoming a very real documented issue. The real scary issue is potential internal engine damage down the road.

- cporteraz, Laguna Niguel, US

problem #5

Mar 182019

Sonata GL

  • Automatic transmission
  • 466 miles

Not something that's expected when purchasing a new vehicle. Salesman picked me up at my house and leaving the driveway the check engine light came on. They reset the computer and the light came on at 750 km again. This time they replaced some wire harness that had something to do with the knock sensors.

- Cris W., Smiths Falls, ON, Canada

problem #4

Apr 062019

Sonata SEL 2.4L

  • Automatic transmission
  • 8,233 miles


Purchased the car in Aug 2018 the 2018.5 Model SEL with 13 miles on her. After the 1st oil change the dealership said they did an update on the ECM, noticed a slight tick from the valves as I've been around cars and worked on older gens before everything went all technological they said it was fine.

Fast forward while driving in the city est 40mph mileage 8,220 the car bucked and check engine light came on and continued to flash and would not go above 2,000 rpms. BlueLINK on screen said the Electronic control module has failed. I was able to granny drive the car to the dealership and since then they have come up with the diagnosis of wiring harness failure. They told me there was 2 other cars in for repair and they have been there for over a month.

This is highly disappointing as I drive part time on the weekends as a Uber driver to make extra cash to afford life. Now I am out of a car and stuck with a payment that I am not able to enjoy. In all honesty I really hope its a whole engine replacement so I can sell this car and make some money back on the 1st and worst decision as to buy a brand new car.

- Kevin O., Jeffersonville, IN, US

problem #3

Mar 292019

Sonata Sport + 2.4L

  • Automatic transmission
  • 4,487 miles

The car went into limp mode (limited to 2000RPM and 60 to 65 MPH) 343 Mi. After getting the 953 recall upgrade to the knock sensors. Vehicle is at the dealer now and waiting on a new wiring harness. The service department states that there is noise on the harness that is impeding them from doing further diagnostics. I've been quoted 2 to 3 weeks of wait time for the harness. Then they can properly diagnose the issue and we go from there. If the knock sensor was correct in putting the car in limp mode, the engine may need to be replaced. The dealer is trying to round up a loaner vehicle for me at this time. They are really pushing the limits of the Nevada Lemon Law with the vehicle being down for 30 or more days within the first year of ownership.

- Shaun B., Henderson, NV, US

problem #2

Feb 202019

Sonata Sport

  • Automatic transmission
  • 9,588 miles

While driving my vehicle on a the free luckily in rush hr traffic, my car suddenly felt like I hit a brick wall and my check engine light came on and began flashing. I was then unable to accelerate past 60mph and felt my car had a very sluggish response when stepping on the gas pedal. I then pushed the Blue Link button to notify them of the issue. They scheduled me for an appointment to take my car into my local Dealership on the very next day.

The dealership got me into a rental and did a Check Engine Light Service/Diagnostic. I got a call a day or two later saying it was the wiring harness and they would have to order the part and it would be in on Monday. Here we are now 9 days from when the dealership received the car and I was notified that the wiring harness was replaced but the engine still knocks and the dealership would be consulting an engineer regarding having the manufacture replacing the engine. I still don't have a definite answer on what is wrong with my car. A 2018 and 9,588 miles I got engine problems already

- ERICA S., Stockton, CA, US

problem #1

Feb 162019


  • Automatic transmission
  • 2,999 miles

Really awful experience after spending hard earned $23k on it, even though it will be fully covered under warranty and maybe a part of an ongoing Recall too. HYUNDAI Sucks!!!

- Abhishek S., Louisville, KY, US

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