general problems of the 2021 Hyundai Sonata - part 2

When attempting to pass other vehicles or under quick acceleration such as an on ramp to the highway, the vehicle will experience a sudden loss of power and oil pressure resulting in a fail safe mode which limits your acceleration and causes a sudden decrease in speed and velocity. The issue results in the oil pressure light illuminating and requires the vehicle to be stopped and completely turned off to reset then once turned back on, the problem is “gone” until a sudden acceleration occurs again, which results in the same issue happening. There is a current recall out for similar models but my VIN is not listed. I have approximately 50k miles on the car, and am the first owner.

When I arrived in the parking lot and selected the r (reverse), the vehicle stayed in the d (drive) although that it was moving backwards and was able to park it. The shift selector was stuck in drive (drive) leaving the vehicle on but not operational. After several attempts to allow the vehicle to cool and the battery to reset, (30 minutes_ later), the car started and took the vehicle to be serviced. The vehicle technician said they had a difficult time diagnosing the vehicle because it was giving different codes. They said that while testing they found the transmission shift selector module was damaged. Not physically but electronically damaged. They also stated that the car could have other problems but that they needed to replace the module first because it could be the cause of the other errors.

The cabin heater started blowing cold air in February. One shop said the car was low on coolant and topped it off. I made an appointment to take the car to a dealer because it's still under warranty (<37k miles). I had to wait 3 weeks. A few days before my appointment, the cabin heater started blowing cold air, again. There is no indicator that the coolant is low. The engine temperature is one of a dozen gauges one can scroll thru, but the "engine overheating" warning started flashing before I thought to check the temperature guage. Smoke came out of the exhaust and, once stopped, from under the hood. There was a risk of an engine fire and/or permanent damage to the engine.

My 2021 Sonata has 32,000 miles & it broke down in the middle of the road. My safety & my daughters safety were at risk. We could have been hit or killed. There were no warning lights. It had to be towed. Repair shop reports the transmission is no good. This vehicle should not have transmission issues. Hyundai will not even cover a rental car. The dealership can’t even work on it for 1-2 weeks. I work & have kids. I need a vehicle. The car breaking down in the middle of the road with no warning is dangerous.

Coolant leak acting like blown head gasket. Coolant was leaking into the exhaust system. Defective ehrs system.

Engine oil plug backed out while driving causing loss of all engine oil in the mountains. Drive time was one hour when oil lamp turned on as we reached our destination. Oil check stick had no oil on it and the whole undercarriage and rear of the car was covered in engine oil. Made an attempt to refill oil and plug fell all the way out and poured the new oil onto the ground. The oil plug is not visible or accessible due to a plastic cover on the underside of the car. The vehicle was towed to elk grove Hyundai dealership for service since they were the last hands on the car for regular maintenance. It was confirmed by the dealership the oil plug backed out on it's own. My family's safety was compromised as we were driving at night in steep mountains during high traffic time. There would be nowhere to go if the engine ceased and would cause an accident on hwy 50 in California. Also a full six quarts of oil was leaking on the back roads, highway, and residential roads, and eventually in a high school parking lot was were the bulk of the oil was spilled. The is an environmental hazard at public school eldorado high school.

Very loud car alarms sounded, e. G. , it sounded like a something like a red alert in an old star trek episode. Warning light indicated engine overheated, extreme exhaust/smoke bellowed out from rear of car while decelerating on highway exit ramp. My wife and I were inside the car during this event. This event happened on 5 pm est December 9 at hamilton avenue exit on ohio 126 cross county highway (ronald reagan highway) in the cincinnati metropolitan area. Had to park car within one mile. I had the car towed to the nearest dealer after it had cooled for 1 +hour. I was afraid the engine was going to explode or catch fire as I was decelerating. The dealer suggests the heat exchanger needed replacement. However, after 45 days, Hyundai has not shipped the heat exchanger that I have been made aware. I am concerned this event may be likely to reoccur and with resulting potential injuries to the occupants inside.

The issue is well known across the dn8 platform, hundreds if not thousands of people have this problem. Car and driver even did an article on a car with this same 2. 5l turbo dct engine having the same problem! the problem is the itms or thermostat housing unit. I first experienced this getting on to a highway, I lost all acceleration, the turbo dropped to 0 psi and I received an engine overheating warning on the dash. After pulling over the car resumed normal driving, but with oil temps running 30-40 degrees higher than normal. Since then, I have had loss of boost and acceleration when passing around cars which has almost caused accidents, oil temps constantly running very high and fans constantly running on full blast even after car is off. I have been to the service center 4 times, and they have failed to "replicate" the issue and stated the fan and oil problem is "normal" which it is not. This problem needs to be addressed before somebody gets seriously hurt due to loss of power unexpectedly while driving. Please help! thank you for your time.

Oct engine stalled exiting i95 in kittery maine. Engine light flashed but did not stay on. Was able to get to safe place but car would not go more than 15mph. Hampton huyndai reported mis-fire but stated it cleared on its own. Oct 17th: engine stalled on highway ramp to i495, nearly causing me to be rear ended by other vehicles. Car would not go more than 15 mph. Engine light stayed on. Towed car to key salem Hyundai, defective injectors, warrantee repair. Oct 23rd: car stalls on i93, was able to take immediate exit and turn engine off. Engine light flashed but did not stay on. Took car in to salem dealership on oct 24th, no code found. Oct 25th: car stalls again on city street. Light stays on, salem dealership replaces cat. Convrtr between oct 26th through Nov 4th. Nov 9th: car stalls again on city street. Light stays on, currently in salem dealership. This is a safety issue, in two cases already this car has nearly gotten me in an accident on the highway. I am seeking arbitration for replacement. I am scared to drive this vehicle. I will have a third invoice pending this next repair.

Unknown.

Since we purchased this brand new vehicle, we have had in the dealership service department at a minimum of 5 times for same issue. The vehicle accelerates while stopped at a light so we have to put it in neutral to keep it from accelerating. Once we take out of neutral and release the break, the vehicle accelerates rapidly without stepping on the gas pedal. The computer system always comes on warning that we need to take to dealership because there are engine problems. Then it goes off and comes on again. We have contacted Hyundai to file a complaint and it has gone no where. We have taken it to Hyundai dealership in tucson and they keep replacing parts per Hyundai manufacturer service tech reps. Per same egr codes. We are taking the vehicle to the dealership again today 9/22/22 because it started again around 9/1/22 and we have been waiting for a loaner car again from dealership for same problems. Meawhile, being forced to drive it due to only owning 1vehicle. Hyundai manufacturer has continued to have dealership change out parts and this keeps happening. The vehicle has just over 25k miles on it to date. The first time we had it in the dealership for this problem was on 4/6/22. We have almost rearended several vehicles and are scared to death to drive this vehicle. It is a safety hazard. We purchased the 2021 Sonata vehicle brand new on 11/24/21 along with the lifetime parts and labor warranty. It had 15 miles on it. We also traded our 2018 Hyundai elantra. We paid off the 2021 Sonata completely in 2021. The total cost of this transaction was $34,294. 74. We have also followed all the maintenance requirements. It is urgent that this complaint is investigated as soon as possible and Hyundai manufacturer take responsibility now before someone gets killed. The vehicle is obviously a dangerous manufactured vehicle.

The contact owns a 2021 Hyundai Sonata. The contact stated that while the vehicle was at an independent mechanic for an oil change, the mechanic diagnosed the vehicle with transmission fluid leaking from the engine. The mechanic informed the contact that the transmission fluid leakage was flammable. The dealer was made aware of the failure but informed the contact that they were backed up with other vehicles and could not diagnose the vehicle for approximately three weeks. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was opened. The failure mileage was 5,600.

The contact owns a 2021 Hyundai Sonata. The contact stated while driving 65 mph and attempting to accelerate, the vehicle failed to respond with the check engine warning light illuminated. The contact also heard a knocking sound coming from the vehicle. The contact pulled over on the side of the road and turn off and restarted the vehicle and the vehicle started operating as designed. The vehicle was taken to the dealer and the contact was informed that the transmission and engine needed to be replaced. The manufacturer was contacted but offered no assistance. A case was filed. The failure mileage was 2,700.