Which parts fail
Components named in complaints (automatic and manual transmissions, CVT, axles, driveshaft, 4WD/AWD).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2012 Hyundai Sonata owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2012 Hyundai Sonata Hybrid. The contact stated that after parking in the driveway and turning the vehicle off, the husband exited the vehicle and walked around to the passenger side. After opening the front passenger-side door, the vehicle erroneously rolled backward down the driveway and crashed into a tree. During the incident, the husband was knocked to the ground and dragged 20 feet down the driveway. During the incident, the husband sustained a head bruise and laceration, an injured leg, and an injured arm. The front passenger also sustained bruised ribs, a head and left knee injury from the vehicle crashing into a tree. Both persons required medical treatment. The cause of the failure was not determined. The vehicle was not repaired. The manufacturer and local dealer were notified of the failure but no assistance was offered. …
The contact owns a 2012 Hyundai Sonata. The contact stated while driving at various speeds, and depressing the accelerator pedal the RPM inadvertently decreased. The contact stated that the traction control warning light was illuminated. The contact also stated that while exiting the vehicle he noticed that the brake lights were still illuminated. The contact called Cochran Hyundai of Monroeville (4520 William Penn Hwy, Monroeville, PA 15146:[phone]) and Bowser Hyundai (1001 Clairton Blvd, Pleasant Hills, PA 15236: [phone]) and made them aware of the failure. The vehicle was not diagnosed or repaired. Upon investigation, the contact associated the failure with TSB: 15-01-056; however, the VIN was not included. The manufacturer had been informed of the failure. The failure mileage was approximately 50,500. The contact paid for the replacement of the defective part.
The contact owns a 2012 Hyundai Sonata. The contact stated while driving 30 MPH, the vehicle downshifted unintendedly and decelerated. The contact stated that she shifted into neutral(N). The contact pulled over to the side of the road and remained there for several minutes. The contact was able to continue driving; however, the failure recurred while driving. The contact stated that the failure had been recurring increasingly. The vehicle was taken to the dealer, where the failure recurred while the vehicle was being test-driven; however, the dealer informed the contact that they could not determine the cause of the failure. The dealer informed the contact that the steering wheel needed to be disassembled to inspect the paddle shifters. The vehicle was not diagnosed nor repaired. The manufacturer was notified of the failure. The failure mileage was 100,300.
The contact owns a 2012 Hyundai Sonata. The contact stated that after starting the vehicle, the contact attempted to shift into gear, but the transmission failed to shift as intended. There was no warning light illuminated. The contact pressed the release button and the transmission shifted; however, the vehicle was driving abnormally. An independent mechanic was contacted and stated that the vehicle might be experiencing the failure listed in NHTSA Campaign Number: 14V434000 (Power Train) and advised to contact the local dealer. The vehicle was not diagnosed or repaired. The dealer was contacted and stated that the vehicle was not included in the recall. The manufacturer was not contacted. The failure mileage was 170,000.
This is a 2012 sonata hybrid. The vehicle popped under the hood when my wife was driving to visit her father. My son opened the hood and fire started shooting out from next to the exhaust manifold. The car was just into Gurnee Hyundai for service. They had the car for a month and a half. I still don't think that they did anything when they had it. Anyway, the car burnt completely to the ground in the front engine area. I already contacted Hyundai America, and, even Hyundai and South Korea. This happened on September 8th. I have pictures, I also have the warranty individual who inspected the car before the dealer worked on it, or I have the warranty information. They have the documentation.
The contact owns a 2012 Hyundai Sonata Hybrid. The contact stated that once car has warmed up, while driving at low speed or starting to move after a stop, she vehicle hesitated and stalled while depressing the accelerator pedal. This is a serious risk hazard as the car barely moves at intersections where it is a risk of getting hit by incoming cars. There was no warning light illuminated. The contact had taken the vehicle to multiple independent mechanics as well as hyundai dealerships who were all unable to diagnose the failure due to no warning lights illuminating on the instrument panel and no codes getting registered in the ECU. The contact then got the car evaluated by another Hyundai dealership in order to exchange it for a new vehicle and mentioned this problem. …
Hybrid System Malfunction. The "Hybrid System Warning! Safely Stop and Do Not Drive" appeared on the vehicle dashboard. While traveling on the highway or in town the vehicle will want to slow down then stop. The dealership's (Wyatt Johnson Hyundai) Clarksville, TN, maintenance tech have troubleshot the vehicle. Since my daughter and I have owned the vehicle, it has been seen by the dealer a few times during this time a transmission replacement was completed for the Hybrid System Malfunction, which did not solve the problem and I had to pay out almost $6,000. Still, same issue arises and also, I was told by another tech that the transmission is sealed and should not have been opened. The only thing we heard from the dealer(Wyatt Johnson Hyundai) was to come and pick up the car. When my son-n-law went to pick up the vehicle, the engine was still torn apart. …
Car completely shut down suddenly and spontaneously without ANY warning while my husband and I were driving on a very busy major highway at night. We were unable to do ANYTHING to control the car and could have died, been seriously injured, or caused death or injury to other drivers. We were then towed off of the highway after calling for help. We don't know firsthand exactly what failed. We were aware of our engine burning oil and had been to Huffines Hyundai multiple times previously for an oil consumption test at their recommendation. Upon completion of this test process no solutions for repair were offered, and we were never warned of any danger in driving it. We have found out via our own research that our car has a defective engine. This specific engine has been the subject of at least one class action lawsuit and Hyundai is well aware of its dangers. …
The contact owns a 2012 Hyundai Sonata. The contact stated that while her daughter was driving at undisclosed speeds, the vehicle was jerking abnormally. The passenger's side front tire was extremely hot. The contact stated that the RPM increased to high, and the vehicle lost motive power while driving. The contact stated that while the accelerator pedal was depressed, the vehicle was slow to respond. There was an abnormal electrical burning odor detected. The vehicle was hard to start. The contact stated that the check engine and ABS warning lights were illuminated. On several occasions, the vehicle was taken to the local dealer, who was unable to retrieve any DTC trouble codes. The bearing was fine but was replaced at the owner's request. The mechanic test-drove the vehicle for five hundred miles but was unable to duplicate the failure. …
Knock sensor needs to be replaced upon evaluation of an inspection on March 27, 2026. It failed a mission codes and upon my understanding the knock sensor one circuit range performance pink wonder single sensor is an engine failure as well as I did an ODB test myself on May 19 of 2026 for the Knox sensor as well and the check engine dominator reading at 2111 the the code indicated that bank one Knox and electrical circuit was out of it upper range or had it perform problem for a predetermined period of time and the code is P0326 and the secondary DTC is a combustion vibration sensor a circuit range performance which affects the powertrain. …
Related recalls
Power train › Automatic transmission
Hyundai Motor Company (Hyundai) is recalling certain model year 2011-2014 Sonata vehicles manufactured December 11, 2009, through May 29, 2014. In the affected vehicles, the transmission shift cable may detach from from the shift lever pin.
Remedy: Hyundai will notify owners, and dealers will inspect and, as necessary, repair the connection between the shift cable and shift lever, free of charge. The recall began in September 2014.
Transmission complaints in other Sonata years
Frequently asked questions
How common are transmission problems on the 2012 Hyundai Sonata?
NHTSA has 97 complaints about the transmission & drivetrain of the 2012 Hyundai Sonata, 6% of the model year's 1,558 complaints. The component named most often is automatic transmission (2 mentions).
Is there a recall for 2012 Hyundai Sonata transmission problems?
Yes — NHTSA recall 14V-434 (automatic transmission, Jul 18, 2014). Recall repairs are free at authorized dealers.
At what mileage do 2012 Hyundai Sonata transmission problems start?
Half of the complaints with a recorded mileage happened before about 86,000 miles, and 13% before 25,000 miles.
Is it dangerous?
Owners linked 8 crashes, 2 fires and 6 injuries to transmission & drivetrain problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.