2012 Hyundai Sonata Problems

What owners report

Owners of the 2012 Sonata most often describe engine trouble: knocking or ticking noises, stalling or losing power while driving, oil burning with no visible leak, and in some cases a seized engine needing replacement. A second large group of complaints concerns the brakes and exterior lights, where brake lights stay on after the pedal is released or rear bulbs and sockets repeatedly fail. Steering noise and airbag or dashboard-light concerns also come up, typically well past 70,000 miles.

1. 1
   Engine

   Engine knock, stalling and engine replacement

   • 418 complaints (27%)
   • median 88,500 mi at 7.0 yrs old (284 state mileage)
   • 33 mention a crash, fire or injury
   • owner-quoted repair $1,450 (median of 24 quotes)
   • filed 2011–2026

   Complaints describe a knocking or rattling noise from the engine that often comes before the car loses power or shuts off while driving at highway or around-town speeds. Many report the check engine or oil light coming on, and several say a dealer diagnosed engine seizure or failure and quoted a replacement engine. Some mention a prior recall engine repair after which the noise or loss of power returned; others say no diagnostic codes were stored and the cause was not identified. Mostly reported between roughly 70,000 and 130,000 miles, though a few describe it below 60,000 miles.

   Recall 15V568000Recall 18V9340002 related service bulletins

   What to check: Ask for the full service history and whether any engine recall or replacement work was done, and listen for a knock or tick at cold start and during a test drive. Check the oil level and look for a fuel or exhaust smell, since complaints mention oil use without visible leaks.

   2 excerpts from owner complaints in NHTSA records

   “My car stalls, lags and shuts off while driving and has a strong scent of exhaust and uses an awful amount of oil but there are no visible oil leaks. There are no check engine lights on. I have taken it to the muffler shop who states no exhaust leaks are found. My local gateway and mike morgan hyuandi says it throws no codes when put on the diagnostic machine so I cant find out the issue. …”

   NHTSA complaint #11364610, filed 2020-10, 130,000 miles

   “My car stalls all of the sudden out the blue during driving sometimes it kills causing me to almost get hit a couple times because it just goes out during driving. It has a misfire and a strong scent of exhaust coming from the car. I have take it to mike morgan hyuandi in louisiana where the mechanic clearly tells me they feel the misfire and smell the exhaust but no engine lights are on so no codes can be read and they cant do anything. …”

   NHTSA complaint #11378083, filed 2020-12, 141,062 miles
2. 2
   Brakes

   Brake lights stay on or rear bulbs keep failing

   • 197 complaints (13%)
   • median 90,000 mi at 7.2 yrs old (111 state mileage)
   • 17 mention a crash, fire or injury
   • owner-quoted repair $950 (median of 12 quotes)
   • filed 2013–2026

   Owners describe rear brake lights staying lit after the pedal is released, sometimes with the car parked and off, which drains the battery and makes other drivers think the brakes are applied. Others report replacing rear bulbs repeatedly and finding the socket or housing melted, with the bulb no longer removable. Some link the brake light behavior to warning lights on the dash and to odd shifting or stability-control behavior. Reported from about 55,000 to 130,000 miles, often noted while parked or shortly after starting the car.

   Recall 15V759000

   What to check: With the car off, look at the rear lights to confirm they are not lit, and have someone press and release the pedal while you watch. Check the rear bulb sockets and housings for melting or a burning smell, and ask whether the brake light switch or stopper pad was ever replaced.

   2 excerpts from owner complaints in NHTSA records

   “Brake lights will not turn off, causing other drivers to think I have my foot on the brakes. Also, they do not turn off after I park the car and remove the key from the ignition. I have looked this up and it is a major complaint, but no recall on my vehicle. There was a recall in jan of 2016, but not on my car. It was for the brake light switch plunger.”

   NHTSA complaint #11321097, filed 2020-04, 56,000 miles

   “My passenger rear light keeps blowing. I have replaced the bulb once a week since I bought the car two years ago. I have been pulled over multiple times, thankfully I was not ticketed and was given a warning all 3 times. The light went out again so I went to change the bulb and the the whole housing unit is melted. Now I am unable to take the bulb out to change it.”

   NHTSA complaint #11406847, filed 2021-04, 138,000 miles
3. 3
   Electrical system

   Electrical faults and no-start conditions

   • 221 complaints (14%)
   • median 95,000 mi at 7.0 yrs old (119 state mileage)
   • 52 mention a crash, fire or injury
   • owner-quoted repair $2,957 (median of 23 quotes)
   • filed 2012–2026

   Complaints describe the car not recognizing the key fob and failing to start after repeated attempts, sputtering or losing power while driving with no stored codes, and in some cases smoke or fire from under the hood or near the driver's door. Others report the hybrid system warning telling them to stop, or a failed body or anti-theft related component. Spread from about 50,000 to 150,000 miles, with a few low-mileage reports.

   3 related service bulletins

   What to check: Test every start cycle, including after the car sits, and check that the key fob works reliably. Ask whether the anti-theft software update and ignition cylinder protector were installed, and look for any signs of wiring or fuse box repairs.

   2 excerpts from owner complaints in NHTSA records

   “The vehicle does not start as it doesn't recognize the key fob. My daughters and wife have been stranded on different occasions as they were not able to start the car. Something is wrong with the electrical as the engine does not recognize the key. I am scared to take the car on long trips as this happens frequently and it can take up to 20 attempts before the engine starts. Please help!!”

   NHTSA complaint #11321554, filed 2020-04, 100,000 miles

   “The vehicle was parked. I tried to turn the car on but it didn't come on, and then I noticed it smoking under the hood. About 5 minutes later there were flames coming from under the hood and quickly spread to the rest of the car.”

   NHTSA complaint #11404189, filed 2021-03, 122,000 miles
4. 4
   Air bags

   Airbag warning light and cracked dashboard

   • 123 complaints (8%)
   • median 81,598 mi at 6.7 yrs old (67 state mileage)
   • 20 mention a crash, fire or injury
   • owner-quoted repair $1,200 (median of 9 quotes)
   • filed 2012–2026

   Owners report the airbag warning light coming on without a collision, often alongside cracks in the passenger-side dashboard near the airbag area, which some attribute to heat. A few describe a side curtain airbag deploying on its own while the car was parked, and one describes the steering-wheel airbag area appearing to separate. Mostly reported between about 50,000 and 100,000 miles, in several cases after the car sat parked in hot weather.

   Recall 12V352000Recall 18V1370003 related service bulletins

   What to check: Confirm the airbag light comes on briefly at startup and then goes out, and check the dashboard for cracks around the passenger airbag. Ask whether the airbag control module and clock spring recalls or warranty extensions were completed for this vehicle.

   2 excerpts from owner complaints in NHTSA records

   “My airbag light is on have had no accidents and on the steering wheel it's seems to be open on its own a little bit could I drive my car this way? I was just routinely driving my car the light came on went off came back on and it's still on it's been a week now”

   NHTSA complaint #11300683, filed 2020-01, 110,000 miles

   “About 2+ months ago, I had my car serviced for brakes, oil change, and filters. Within a day or two I noticed a crack on my dashboard near the airbag passenger unit. Thinking it was florida heat related, I paid it no attention. During this covid pandemic I now see that the other side of the passenger airbag notation on the dashboard is cracked as well, and the last time my husband and I ran an errand, the airbag warning light went on. …”

   NHTSA complaint #11323639, filed 2020-05, 96,179 miles

Buying note. This model year has a long list of open recalls and known engine concerns, so a pre-purchase inspection by a shop familiar with these cars and a check of outstanding recalls by VIN are worth the cost. Prioritize examples with documented engine and brake light switch work, and budget for possible engine oil consumption or replacement.

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.