When the accelerator pedal is depressed all the way to the floor (past the normal full accelerator position), the transmission will automatically engage kickdown, i.e. immediately shift down to a lower gear.
If the accelerator pedal is released from the kickdown position, the transmission will automatically shift up again.
Safety function
The transmission control module is equipped with a downshift protection feature to help prevent the engine from overheating.
In some conditions, the transmission will prevent downshifting/kickdown if this would lead to such high engine speed (rpm) that the engine could be damaged. If the driver still attempts downshifting or kickdown at a high rpm, nothing will happen and the original gear will remain selected.
With kickdown, the vehicle can downshift one or more steps at a time depending on the engine speed. The vehicle upshifts when the engine reaches its maximum rpm to prevent engine damage.