2018 Hyundai Sonata Common Problems & Defect Telemetry

“I recently had the 9C2 Emissions recall update performed on my car, and since the update my car drives like total garbage after a cold start. It hesitates to accelerate, it bucks when trying to accelerate, and it’s to the point the engine is about to stall. I took it back to t...”

“The paint on all parts of the car is completely coming off down to bare metal. It’s as if the car wasn’t prepped to receive paint. Every Hyundai I pass that’s white the paint is coming off. There is also an internal engine oil leak where I’m losing 4qts of oil a week.”

“The lower aluminum engine oil pan developed a structural hairline fracture ("micro-crack") directly along the factory casting ridge adjacent to the drain plug. The component failed without any external impact, road hazard, scraping, or underbody damage. The failure was officia...”

“I was only in the car for about 4 minutes then came to a stop light. Once the light had turned green I pressured down on the gas, my car rolled for a second then died on me, causing it to go into accessory mode. Instantly three lights came on: the check engine light, battery l...”

“We think there’s an issue with the abs module and wheel speed sensor because we started having a problem where the brakes wouldn’t work or would stutter. The car would shake real bad it would make an awful grinding sound but normally only when trying to stop at higher speeds o...”

“The vehicle had safety and mechanical problems shortly after purchase, even with low mileage. The issues included warning lights, abnormal noises, repeated mechanical failures, and poor performance that affected the safe operation of the vehicle. These problems started early a...”

“I recently had the 9C2 Emissions recall update performed on my car, and since the update my car drives like total garbage after a cold start. It hesitates to accelerate, it bucks when trying to accelerate, and it’s to the point the engine is about to stall. I took it back to t...”

“Check engine light solid/engine failure while driving. 2018 Sonata SE purchased new in fall 2018. Around 50,000 miles started noticing oil level drop and had to add more before next scheduled change. Dealership service center said I just had to shorten the mileage between chan...”

“Following completion of Service Campaign 9C2 (ECU software update, TSB 25-01-087H) at a Hyundai dealership, my 2018 Sonata immediately exhibited drivability changes that were not present before the service. Symptoms include altered shift timing, hesitation, and rougher throttl...”

“The lower aluminum engine oil pan developed a structural hairline fracture ("micro-crack") directly along the factory casting ridge adjacent to the drain plug. The component failed without any external impact, road hazard, scraping, or underbody damage. The failure was officia...”

“The oil pan is starting to crack, a small drip is now happening but dealership says it could spilt and cause the engine to seize while driving. The pan looks very flimsy compared to my Ford and Toyota.”

“The contact owns a 2018 Hyundai Sonata. The contact stated that while driving approximately 60 MPH, the vehicle started to vibrate roughly. The contact felt the vibration in the steering wheel. The check engine warning light was illuminated. The contact slowed down and pulled ...”

“We think there’s an issue with the abs module and wheel speed sensor because we started having a problem where the brakes wouldn’t work or would stutter. The car would shake real bad it would make an awful grinding sound but normally only when trying to stop at higher speeds o...”

“Intermittent no-crank, no-start condition. Dash lights illuminate, push-button start produces no response. Brake pedal applied. Vehicle becomes immobilized without warning. I’ve been stranded on multiple occasions. Unable to commute to work, or home. Most recently on December ...”

“During multiple dealership visits in 2025, my 2018 Hyundai Sonata Limited 2.0T was repeatedly returned in unsafe condition. Southern Hyundai installed both front CV axles and torqued them incorrectly. The right axle was later confirmed under-torqued by about 50 ft-lbs, and the...”

“The three airbags in the car (on the driver's weel, driver's knee, and the passenger's side) deployed while driving on a normal street at a speed of 50 miles/hour. This is an unexpected behavior of a car at a normal speed. I need help to fix this car and know what is the reaso...”

“I am Detective ... #XXX with Austin Police Department Vehicular Homicide Unit and I worked a fatal crash .... The damage to the vehicle two vehicle should not have caused a death. The airbag became detached from the steering wheel and impaled into the drivers chest. I do have ...”

“On 05/27/2025, my rear back-up camera started to malfunction. Last week my dash started to malfunction electronically. When I would start my vehicle, all of the lights would start to turn on and stay on on my dash. My speedometer would not move while I was driving, so I could ...”

“The contact owns a 2018 Hyundai Sonata. The contact stated that while operating the vehicle, there was an abnormal fuel odor inside the vehicle. The vehicle was taken to the local dealer and was diagnosed with an inoperable low-pressure fuel pump. The contact was informed that...”

“I was only in the car for about 4 minutes then came to a stop light. Once the light had turned green I pressured down on the gas, my car rolled for a second then died on me, causing it to go into accessory mode. Instantly three lights came on: the check engine light, battery l...”

“Throttle response intermittent problem no acceleration since new. No codes available. When entering traffic engine stall factor flat spot. Been to dealer many times (Bud Clary) and just recently (04/26) confirmed the fuel pump is the problem. Unable to confirm because of no "c...”