2015 Hyundai Sonata Problems

What owners report

Owners of this model year most often write about the engine: knocking noises, stalling or a sudden loss of power, and in many cases a diagnosis that the engine needs to be replaced. A second, related theme is the engine using oil between changes, sometimes without any warning light. Sunroof panel and wind deflector problems, transmission hesitation, and intermittent loss of power steering assist also appear repeatedly in the complaints.

1. 1
   Engine

   Engine knocking, stalling and engine replacement

   • 563 complaints (49%)
   • median 65,000 mi at 4.8 yrs old (295 state mileage)
   • 41 mention a crash, fire or injury
   • owner-quoted repair $3,000 (median of 39 quotes)
   • filed 2015–2026

   Owners describe a knocking, clanking or rattling sound from the engine, often followed by stalling or a sudden loss of power at highway or city speeds. Many complaints say a dealer or independent shop diagnosed engine failure and recommended a replacement engine, sometimes after a bearing failed or metal was found in the oil. Several owners report that a software update, spark plug replacement or other repair did not resolve the problem, and a few mention the failure returning after an engine was replaced. Mostly reported between roughly 70,000 and 140,000 miles, with a number of complaints at lower mileage around 40,000 to 50,000 miles.

   What to check: Ask for service records and whether any engine replacement or engine software campaign has been performed. Listen for a knock at cold start and check the oil level and condition before a test drive.

   2 excerpts from owner complaints in NHTSA records

   “I was driving to work at like 4:00 in the morning it was still dark outside the light turned green and as I hit the gas pedal the car stall it was moving slow so on my right hand side there was a building so I try to make it to the parking lot the car started to power down in a knocking noise started it was a busy morning in the morning work traffic”

   NHTSA complaint #11415669, filed 2021-05, 10 miles

   “I was driving on the highway and heard a rattling sound on the engine then the car turned off. I had it towed 53 miles to the dealership and they told me the car needs a new engine and that they were going to send a request to Hyundai for the engine. They said it would take a couple of days to find out what they say.”

   NHTSA complaint #11387787, filed 2021-01, 112,000 miles
2. 2
   Engine

   Excessive engine oil consumption

   • 138 complaints (12%)
   • median 71,250 mi at 5.2 yrs old (48 state mileage)
   • 5 mention a crash, fire or injury
   • owner-quoted repair $3,000 (median of 13 quotes)
   • filed 2015–2026

   Complaints describe the engine using oil between changes, in some cases a quart or more per week, with no visible leak under the car. Owners report topping off frequently and checking the dipstick to find the level off the stick, sometimes without the oil warning light coming on. Several say a dealer ran an oil consumption test, and some were advised to add oil every 1,000 miles; a service bulletin describes inspection and repair procedures for higher-than-expected oil consumption. Reported from about 50,000 to 125,000 miles, and in a few cases just past a scheduled oil change.

   2 related service bulletins

   What to check: Check the dipstick and ask whether an oil consumption test has been recorded. A low reading on a car that was recently serviced is worth asking about before purchase.

   2 excerpts from owner complaints in NHTSA records

   “Vehicle is going through engine oil very quickly. No evidence of a leak, no evidence of burning. Oil light does not illuminate when oil is low. When I checked this morning, my oil level didn't register on the dipstick - but no warning light came on. I was only 100 miles over my scheduled oil change. Last checked 2 weeks ago and was fine.”

   NHTSA complaint #11339321, filed 2020-07, 80,002 miles

   “The contact owns a 2015 Hyundai Sonata. The contact stated while driving at various speeds, the vehicle backfired and sputtered. Additionally, the vehicle failed to accelerate as needed while depressing the accelerator pedal. The contact stated that the vehicle failed to exceed 20 MPH while driving uphill. Additionally, the contact noticed the presence of strong fumes inside the cabin, which caused her clothes and hair to smell like fumes. …”

   NHTSA complaint #11639185, filed 2025-01, 77,000 miles
3. 3
   Other or unknown

   Panoramic sunroof detaching or inoperable

   Mentioned in 6 of 60 sampled complaints

   Owners describe the sunroof wind deflector coming loose and the panel or glass detaching while driving, in one case shattering. Others report the sunroof simply becoming inoperable. Complaints say dealers diagnosed the need to replace the wind deflector or the roof panel, and several owners note that recall work on the same part had already been done, or that the dealer confirmed a recall applied. Reported from about 70,000 to 110,000 miles, typically at highway speeds when the roof was open.

   Recall 16V726000

   What to check: On cars with the panoramic roof, open and close it fully and inspect the wind deflector and panel seams. Ask whether the sunroof recall work was completed and whether it has come loose since.

   2 excerpts from owner complaints in NHTSA records

   “Wind deflector previously fixed twice before via recalls came loose again. I was on the interstate with the sunroof open. Had to hold it down to prevent damage until I could get off the freeway safely. Had to manually hold it down as I closed the roof while outside of the car.”

   NHTSA complaint #11328681, filed 2020-06, 109,000 miles

   “I was driving with my sunroof closed and the whole thing came detached. The window shattered. And part of the piece that holds it fell off. I see a recall previous for this issue.”

   NHTSA complaint #11387355, filed 2021-01, 74,000 miles
4. 4
   Transmission and drivetrain

   Hesitation, lurching and reduced-power mode

   • 108 complaints (9%)
   • median 42,500 mi at 4.5 yrs old (64 state mileage)
   • 10 mention a crash, fire or injury
   • owner-quoted repair $1,100 (median of 6 quotes)
   • filed 2015–2026

   Owners report the transmission stumbling and hesitating when accelerating again after braking to slow down. Others describe a jolt or lurch when pulling away after the car has sat for a day or two, or a car that will not accelerate above a low speed with the check engine light on. Complaints mention dealers applying a software update, and one owner says the update did not last. Reported from about 65,000 to 160,000 miles, in both city and highway driving.

   2 related service bulletins

   What to check: During the test drive, slow to a stop and accelerate again a few times to feel for hesitation or a lurch. Ask whether any transmission or engine control software updates have been applied.

   2 excerpts from owner complaints in NHTSA records

   “We bought our Sonata in 2017, since then it has gone into limp mode (while in motion every time) three times. We took it to the dealership the first time it happened and they claimed it needed a software update . The update didn't last too long because it went into limp mode once again. We took it back to the dealership (as instructed by the dealership) and they refused to provide services until a diagnosis fee was provided; even though they told us to bring it back if it happened again and they would fix the problem at no cost. …”

   NHTSA complaint #11377908, filed 2020-12, 160,000 miles

   “When your applying brake on the 2015 Sonata hybrid to slow down when u hit gas again the transmission stumbles and hesitates to speed up again. It happens all the time at any speed.”

   NHTSA complaint #11406978, filed 2021-04, 103,708 miles
5. 5
   Steering

   Intermittent loss of power steering assist

   • 69 complaints (6%)
   • median 65,000 mi at 4.6 yrs old (41 state mileage)
   • 3 mention a crash, fire or injury
   • owner-quoted repair $2,750 (median of 6 quotes)
   • filed 2015–2026

   Complaints describe the power steering assist dropping out while driving, with a warning message on the dash and the wheel suddenly becoming hard to turn; some owners say restarting the car restored assist. One owner reports steering locking briefly and the electronics resetting mid-turn, and another describes losing power to both the engine and steering with a hybrid system warning. Complaints say dealers diagnosed a loss of power steering assist. Reported between about 55,000 and 116,000 miles, at both city and highway speeds.

   Recall 14V325000 · DO NOT DRIVE

   What to check: Ask whether any steering or wiring harness recall work has been completed. During the test drive, watch for a steering warning message and note any unusually heavy effort at low speed.

   2 excerpts from owner complaints in NHTSA records

   “While driving on a busy four lane I entered a turn lane to cross traffic. Immediately after I engaged the accelerator the vehicle lost all power and steering, with a alarm stating 'hybrid system warning-do not drive'. One vehicle narrowly missed hitting my car, (as it completely lost all power and steering and left me stuck in the middle of on coming traffic). Researching today I see this is common between 2012-2016 especially. This is a very dangerous situation that was narrowly avoided.”

   NHTSA complaint #11354220, filed 2020-09, 116,000 miles

   “My 2015 Hyundai Sonata has a problem of steering lock for 1 second while driving on road when turning left /right. On march 3rd I was driving on ga-317 s and want to take right turn on ga-120.as soon as I took the turn and was about to merge in the lane then suddenly my car's steering got locked for a while (around 1 second) and unlocked again automatically and my car's computer system also restartedbluetooth disconected and radio started loke when you start the car .any further delay in unlocking the steering could cause serious acccident. …”

   NHTSA complaint #11316380, filed 2020-03, 110,130 miles

Buying note. The engine is the main thing to vet on this model year, so a documented service history and an oil consumption check are worth more than low mileage alone. Also confirm whether the sunroof and steering-related recall work has been completed before you buy.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.