While I was driving the car stopped and wouldn't start, all the lights came on, message on dashboard read "hybrid system error" "check charging system" than everything went off, no power, no emergency lights, this in the middle of a busy street. Luckily a sheriff's was nearby and rerouted cars. Very scary. Seems I am not the only one that has a similar experience. This happened when I was going to work at 7:45am at S very busy intersection. Car is at mechanic's shop.

- Los Angeles, CA, USA

Reported originally in NHTSA 11084763 while driving on highway at highway speed again the car died with no warning when the hybrid system went out and lost all acceleration and ability to steer car. The car would start but would not engage in gear and was in "limp" mode but was unable to "limp" off the highway. Car was towed to dealership and the electric water pump to cool hybrid system was bad but I had taken the car to the dealer twice before to complain that the car was not driving or accelerating properly. I kept being told that it could not be replicated and "no codes" are being thrown. This is a serious safety problem that Hyundai should fix and train their service people to identify before the car just dies on the highway with no warning. This is the second major problem I have encountered with this Sonata hybrid and it is scary when a car just stop unexpectedly on the highway with no warning.

- Pembroke, MA, USA

Vehicle was traveling on freeway at 70 mph when a fatal error code flashed and said stop car after 20 seconds the vehicle stopped and all electrical systems died (not enough time to safely pull to the side (no 4-way flashers operable). Towed to dealer and dealer stated the lithium battery was 3 volts causing the issue and blowing the safety plug causing the vehicle to stop with no electrical operation. I asked why there is no warning that allows the driver to know that the lithium battery will fail causing this fatal issue. They confirmed that there is no advanced warning, when the battery dies it shuts down the vehicle quickly within 20 seconds. This happened at night on a busy freeway and could have resulted in a major traffic collision as the vehicle is black.

- Murrieta, CA, USA

Car has 65K miles. Warning "chime" came on, total loss of power, pulled of road safely. Warning light on dash came on... hybrid system warning...safely stop... do not drive...then....check brake....then back to hybrid system warning...do not drive....then back to check brake. And on and on. I shut off the car after a minute and restarted car drove another several miles and then same situation. I have seen a video post on youtube and have seen other posts as well and one with a vehicle having only 3500 miles. I'm trying to see that this should be a major safety concern as shutting down completely is not acceptable and totally unsafe.

- Aurora, IL, USA

Was driving vehicle and "check charging system" message displayed on the console. The vehicle lost power, I could not accelerate so I had to manevour to the far right of the freeway to come to a stop. Turned off the vehicle then re started. Check engine light remained on.

- Encino, CA, USA

The car does not accelerate from a stop position at a light or during stop and go traffic on the highway. The car also jerks from transmission problems causing the driver to be distracted.

- Miami, FL, USA

Hybrid system warning! safely stop and do not drive. 1st occurrence miles - 42,143. 2nd occurrence miles - 42,276 this is the second time in a week I'm taking the car into the dealer for the same hybrid malfunction. The car gave me the hybrid warning, then while trying to pull the car over safely, the car lost all power and stalled. This occurred on a busy city street. Steering is also an issue, the car does not track strait. The car's steering constantly has to be corrected to track strait.

- Glendale, CA, USA

Car stopped in the middle of local street road and not able to be driven to move to side of road. Car towed to delaer for repair. Want to warn about this danger to other owners. We were lucky since no one was behind us when the car immediately stopped in the middle of the road. Car was repaired by delaer as follows. Tech scan codes and found codes U1007, P1775, P1774. Tech check A/T fluid, red color, smell normal. Reset codes, codes come back. Tsb provided by tech line. Tech follow tsb#14-hc-003, result to replace oil pump control unit and recheck. After replacing oil pump control unit, same problem present. Tech replace oil pump, and found open yellow wire from oil pump unit to oil pump. Car runs normal and no codes present at this time. Tech try to put the old oil pump and pump module back in, problem happened again. Tech confirm the pump and module are bad. New oil pump and module reinstalled. Car under warranty and repair was successful. Delaer did a good job keeping me informed on the progress, even though it took longer than expected to repair the car.

- San Jose, CA, USA

I bought this 2013 hybrid new about 6 months ago. There are 2 main issues I have had with the car. First: The problem is the car sometimes goes about 3 mph for approximately 25 feet before lurching with great acceleration. I drove with the 'energy flow' mode on the display to see what was showing when this problem was occurring. According to the owner's manual the display was showing the "engine generation/motor drive" (to decelerate the vehicle, engine braking is used while the regenerative braking is applied and also charges the hybrid battery. [engine>battery>wheel]). this sounds like a deceleration mode, but should this be happening when my foot is pressing the gas pedal? it has occurred when I have slowed to make a left turn and also when accelerating from a dead stop. It happens when I am applying steady pressure or pumping the pedal. This can be a huge potential problem/accident waiting to happen if I am attempting to turn or cross a road with oncoming traffic because I may not be moving fast enough to cross before the traffic gets to me. Even if they were over a hundred feet away when I started the turn/to cross the intersection. Second: As has been previously mentioned by others, there is a 'thump' felt at times while braking. It is felt in the driver's seat and through the brake pedal and also felt by the passenger's through their seats. The best way to describe it would be the feeling of being rear-ended and pushed forward several inches. As driver, my head is usually an inch or two away from the head rest and when this happens my head hits the headrest or the headrest hits my head. The brake pedal itself is not affected, as there is no feeling of losing the brake/not slowing down. It's just a 'thump' felt.

- Griffin, GA, USA

Day after purchase, beeps and notification to pull over and check charging system. Had car towed one week later car was returned to us. Dealer installed a new battery. Running fine except brakes make a noise when depressed quickly. March 28th, 11 months later coming home from Florida, driving on interstate 95 late at night in stop & go traffic, beeps and notification to pull over and check charging system. Pulled car over shut off. Restarted car and continued driving. Check engine light stayed on for 24 hrs. Returned to dealer that week could find nothing wrong with charging system. And could not duplicate braking sound at dealership, but still making noise sporatically. May 15th, late on a Saturday night, stopped to make left hand turn, I started to accelerate, half way into the turn, car would not accelerate, bells and notification to check charging system. With traffic coming towards me, I had to shut down engine and restart again. If oncoming traffic was slightly faster I would have been hit. Check engine light stayed on overnight but went off the next day. Returning to dealer this week. Don't expect any positive results as last time they said they cannot find anything wrong. I loved my car, however driving it now makes me very nervous!

- Cape May, NJ, USA

The Sonata hybrid has a major flaw and it's the gas mileage. I was told I would get at least 45 mpg with sensible driving and that was a lie. On cold damp morning and after a cold fog there would be condensation all over the front and back windshields to the point where water droplets would run onto the dashboards and back seats. Also the car has a safety issue with the low beam head lights at night especially in the country. At 50 mph you out run your head lights and can't see far enough ahead of you to stop in time if something runs across in front of you.

- Lancaster, SC, USA

The vehicle lurches forward during deceleration thus pulling pressure off of the brake pedal and causing you to put even more pressure on the brakes to compensate. Vehicle will slide on icy roads at this point. Vehicle also has little to no acceleration on electric motor after the vehicle is hot. Making a left turn from a stop with oncoming traffic is hazardous since the vehicle can take up to 7 seconds before it accelerates enough to complete the turn and clear the oncoming lane. Both problems seem related. The first would appear to be free wheeling with no engine type braking applied while switching from engine to electric. The second would be from no electric motor engagement during initial acceleration from a stop or slow to turn maneuver.

- Stow, OH, USA