Hyundai Sonata: Cruise Control / Cruise Control will be canceled when

Hyundai Sonata LF 2014-2019 Owners Manual / Driving your vehicle / Cruise Control / Cruise Control will be canceled when

Depressing the brake pedal.
Pressing the CANCEL switch located on the steering wheel.
Pushing the CRUISE button. Both the CRUISE indicator and the SET indicator will turn OFF.
Moving the shift toggle switch into N (Neutral).
Decreasing the vehicle speed lower than the memory speed by 5 mph (10 km/h).
Decreasing the vehicle speed to less than approximately 20 mph (30 km/h).
The ESC (Electronic Stability Control) is operating.
Downshifting to the 2nd gear in Manual shift mode.

Information

Each of the above actions will cancel Cruise Control operation (the SET indicator light in the instrument cluster will go off), but only pressing the CRUISE button will turn the system off. If you wish to resume Cruise Control operation, push the toggle switch up (RES+) located on your steering wheel. You will return to your previously preset speed, unless the system was turned off using the CRUISE button.

To decrease Cruise Control speed

Push the toggle switch (1) down (SET-) and hold it. Your vehicle will gradually slow down. Release the toggle switch at the speed you want to maintain. Push the toggle switch (1) down (SET-) and ...

To resume preset Cruising speed

Push the toggle switch (1) up (RES+). If the vehicle speed is over 20 mph (30 km/h), the vehicle will resume the preset speed. ...

Other information:

Hyundai Sonata LF 2014-2019 Service Manual: Fuel Filler Door Open Switch Repair procedures
Inspection 1. Disconnect the negative (-) battery terminal. 2. Using a screwdriver or remover, remove the fuel filler door open switch (A). Take care not to scratch the crash pad surface. 3. Disconnect the fuel filler door open switch connector (A). 4. Apply ...

Hyundai Sonata LF 2014-2019 Owners Manual: To set Cruise Control speed
1. Push the CRUISE button on the steering wheel to turn the system on. The CRUISE indicator will illuminate. 2. Accelerate to the desired speed, which must be more than 20 mph (30 km/h). 3. Push the toggle switch (1) down (SET-), and release it. The SET indicator light will illuminate. 4. Releas ...