The contact owns a 2012 Hyundai Sonata Hybrid. The contact stated while driving 50 mph, the vehicle loss power and decelerated to 25 mph. The check engine warning light was illuminated. The vehicle was taken to the local dealer, but the vehicle was not diagnosed or repaired. The manufacturer was notified and the contact was referred to the local dealer for assistance. The failure mileage was unknown.

- Frankfort, KY, USA

Yesterday the car drove fine untill about an hour before I went home. Then it started with the bumping/jerking when switching from electric to gas. Worse than it has ever been. Then the revving started, more than usual, and wouldn't accelerate. Then it was like the throttle stuck. Got the revving noice, but the eco wasn't burried at red, for about 1/4 mile before I was able to pull over into a parking lot. Shut off the car. Restarted and drove 1 mile to home. Revved a few times in that period.

- Goose Creek, SC, USA

While driving the car will randomly rev very high it started about 3 weeka ago while driving at around an average of 45mph in city. It was initially just revving 3-4 times until I hit the break and it was isolated to one incident per drive. But last night after driving on I-25 at highway speed I turned to a slower busy street more stop and go traffic and the car started revving again only this time it did not stop after one incident. As soon as I hit the accelerator it went into a revving fit. And didnt stop I couldn't even drive it because I could not get it to accelerate. I tried turning off blue drive and tried shifting down to 1st gear so I could at least make it at 10-15mph but it revved up even in manual gear. I had to park it for the night in a pretty sketchy neighborhood and call an uber. The system didn't populate any codes and no service lights came on. Then, this morning when I went back to get the car to a mechanic and it was accelerating fine though it was sluggish. I managed to make it 2.5 miles to a mechanic without incident but still no service engine light.

- Lakewood, CO, USA

While trying to accelerate at freeway speeds (50-60mph), the "eco guage" revs up but the car will not accelerate - slows down in the middle of traffic. The oil pressure warning lamp flickers on and off as well. After the car is stopped and turned off, the car functions normally. Mechanics are unable to retrieve any codes from the system. The car has intermittantly dropped into this mode at least 10 times since we first experienced the problem in July 2018. The problem occurs at freeway speeds causing the car to rapidly decelerate in fast moving traffic with no advance warnings. This situation requires immediate evasive action to remove the car from high speed traffic lanes so it can be shut down and towed to the Hyundai dealer. My wife and I consider this a life-threatening situation as it has occurred in places such as the bay bridge (with no shoulder) and a lengthy underwater tunnel (again with no shoulder). We have taken it to the Hyundai dealer service shop four times. They have replicated the problem and have tried various repairs - replace transmission oil pump, replace inhibitor switch, install new auxilliary battery, and - finally - replacing the transmission. Even after the transmission replacement, the car shut down while the mechanic was test driving it and provided a code to replace the crankshaft position sensor. The mechanics still are not certain they have fixed the problem. It appears as if Hyundai is aware of the problem as their technical support staff have a protocol for repairing the car. Given the intermittant nature of the problem, the fact that it occurs at high speeds, and the potential danger of having your car rapidly decelerate on busy freeways, I think this is a safety issue that needs to be addressed by Hyundai. Attached is the original service record that describes the problem (date 8/6/18). The most recent occurrence was 11/27/18.

- Incline Village, NV, USA

The contact owns a 2012 Hyundai Sonata hybrid. While the vehicle was in reverse, it jerked and an abnormal noise was heard coming from the rear end. When the contact depressed the accelerator pedal, the vehicle failed to accelerate and then accelerated independently. There were no warning indicators illuminated. The vehicle was not taken to a dealer or an independent mechanic for diagnostic testing. The manufacturer was not notified of the failure. The approximate failure mileage was 117,000.

- San Diego, CA, USA

The contact owns a 2012 Hyundai Sonata hybrid. While driving various speeds or making a turn, the vehicle would sputter and then stall without warning. In addition, the vehicle experienced a drastic reduction in speed. When the accelerator pedal was depressed, it traveled to the floorboard, and then the vehicle would suddenly accelerate. The vehicle was taken to the dealer (bob brady auto mall, 4025 E boyd rd, Decatur, il 62521, (217) 876-3800) where it was awaiting diagnostic testing. The contact stated that a possible cause of the failure could be the wastegate actuator. The manufacturer was notified of the failure and the contact was awaiting their response. The VIN and failure mileage were not available.

- Decatur, IL, USA

This vehicle has sudden unintended acceleration as well as continued acceleration after the foot is completely removed from the pedal. I have experienced several near accidents as a result of the problem while the vehicle was in motion. The dealer has been unable to fix the problem, which has been reported several times over the life of the vehicle and still has not been fixed.

- Tijeras, NM, USA

While on cruise control at 68mph I was going down a small hill & my car suddenly accelerated from 68mph to 82mph at which point I disengaged my cruise control & the car decelerated. I noted the mileage & took the car to Hyundai. They found no abnormal event in the computer log.this begs the issue that I did have this event occur. I had the compute microcode upgraded to the last rev earlier this year.

- Durham, NC, USA

This problem has been getting progressively worse during the last 6 months. While driving or stopped at a light, the vehicle has sudden unexplained acceleration. The acceleration happens with or without the foot on the gas. When in drive, the driver can remove his foot from the gas and the vehicle continues to accelerate and pick up speed. The condition is extremely hazardous and warrants further investigation.

- Tijeras, NM, USA

Gas pedal on car sticks and stays in acceleration increasing speed. Have to manually pull gas pedal back up from behind pedal. Took to dealer to inspect since they haven't been able to duplicate issue did not fix and if there was an issue it wouldn't be covered under any warranty?

- Albuquerque, NM, USA

When accelerating from a stop, the vehicle takes excessively long time to go from 0-25 mph, so much so, that when merging into traffic it has unpredictable acceleration. At various times I would step on the gas pedal and sometimes it would have a 3-5 second delay before going forward. When it finally accelerates sometimes it has a popping sound and often the car lurches. I have brought it in 3 times for Hyundai to find the problem but each and every time they have said they were not able to find anything wrong with the car.

- Garden Grove, CA, USA

See submission number 10559603 sent prior to this on 1/14/2014: This is a continuation of the explanation of the cruise control/transmission/power train issue experienced with the vehicle since new. The text from that submission continues to its end. "it would appear that the cruise control/power train computer program has some errors in it or needs updating to correct the problem of excessive acceleration when re-attaining a set speed from a coast down that causes the car to go below the set speed before the sensors detect and activate the acceleration required to bring the car back up to the set speed. Then is 'shoots' the car forward at full power-like unintended acceleration might- and send it up to as much as 10 mph above the 'then set' speed I have desired. If there is a corner at the end of the rise, the car can feel out of control during this acceleration as it is at full power during the acceleration phase. The transmission also down shifts 2 or 3 gears during this process which aggravates the fierce acceleration feeling. These incidents have been reported both to the Hyundai dealer and to Hyundai. Hyundai says, take it to our dealer; the dealer says they can find nothing wrong as no dash warning lights are ever showing and their electronic scanning brings up nothing of any kind of problem. This may or may not be exclusive to the Sonata hybrid with cruise control and since many people do not use cruise control on winding rural roads, they may not/never experience the same sensation that can happen often to me. I can deal with it. NHTSA should keep this report on file in case other cruise control or acceleration issues with Hyundai vehicles surface as my report is precisely defined as to what type of road condition it occurs on and what happens. Thank you.

- Sharon, CT, USA

Electrical smell like melting plastic wiring: First incident as noted above; 2nd incident on 1/29/2013, mileage 9227-on vehicle start up (engine warm as it was after earlier driving) same hot, melting wire type smell coming through climate control dash vents; 3rd incident on 4/12/2013-mileage 12,353-hot burning smell through heater vents occurring on/after climbing steep hill for a mile or so; 4th incident-4/16/2013, mileage 12538, location of incident same as 3rd incident, same hill climb, same smell occurring during drive. Reported to dealer. Could not be duplicated during service appt. No further incidents of burning smell to current date: 01/13/2014. Cruise control and transmission gear selection issues: First incident: Around 1/20/2013; subsequent incidents periodically since then to current date of 01/14/2013: When on cruise control, speeds set at anywhere (40-60 mpg for these incidents), on coasting down or flat terrain transmission will shift from 6th (high) gear down to 3rd or 4th and hold that gear with engine rev ving accordingly, until I either manu-shift it back up to 6th, or, perhaps after 10 or more seconds it might shift into higher gear on its own. I have deliberately not disengaged cruise control during these incidents to continue to assess the condition. Related to this is occasional excessive acceleration as car can drop (on cruise) to below set speed as in a dip in the road, and then applying speed to get back to set speed, but, it will accelerate aggressively to as much as 10 mph above set speed before cruise control mode 'back' off the acceleration action, making the car feel like it is 'taking off'. this can happen often on certain roads at same transition points from coasting downward into a dip in the road, then (cruise control) reapplying power to get the car backup to speed. Rest will be sent in a second submission following this.

- Sharon, CT, USA