There is a defect with the transmission control module (TCM) and dual-clutch transmission (DCT). This defect prevents the car from properly accelerating from a stop. The defect manifests in the following ways when pressing the accelerator: unresponsive or sluggish acceleration, jerking, shuddering, failure to shift, stalling and complete loss of power. Typically, the TCM defect manifests in two ways: shuddering/delayed brake release, which has happened over 20 times and loss of power/engine revving out of gear which has occured three times. These issues are unpredictable, unrepeatable and dangerous. I usually experience them while waiting at stop lights in busy intersections. Delayed and unpredictable acceleration and shifting could cause a traffic accident. I've notified the dealership three times and had it serviced once by licensed Hyundai technicians at the same dealership. They couldn't replicate the issue and claimed they had never heard of the problem. There are no warning lights when this issue occurs and the dealship said there were no diagnostic codes indicating the problem. Defective TCM & DCT software is a known issue that resulted in a recall campaign for the 2016 Hyundai Tucson. This issue has been documented in the following vehicles: 2017 Hyundai Elantra Eco, 2017 Hyundai Sonata Eco, 2016 -?" 2017 Hyundai Tucson, 2016 Hyunda Veloster Turbo. Hyundai issued the following service bulletins informing dealerships about the TCU software issue specific to the Tucson: #5NP-X7J3D-10, TSB# 16-01-035, #5NP- S9D9P-10

- Minneapolis, MN, USA

The car shifts from drive mode into sport mode by itself without the driver manually moving the gear shift from drive to sport. This happens randomly, but always when the car is in motion and always in a low gear( usually first gear ). it has happened both when making a turn and going straight ahead, usually when the car starts to move after being stopped like at a traffic light. I can get the car to go back into drive mode by physically moving the gearshift into sport mode and then back into drive mode again. Unfortunately, the most recent episode of this happened when I was pulling into my garage. I was halfway into the garage when the car switched to sport mode by itself. The car was still in motion instantly started moving faster and in seconds it hit the back wall of the garage.

- Pennsburg, PA, USA