Set engine speed

This function is used to change the engine speed.
Note:
It is possible to adjust the engine speed between 900 - 1300 rpm. There is also an option to select "Normal", Which makes it return to normal engine speed.
Preconditions for the test:
Procedure:
  1. Start the function.
  2. Select desired rpm in the list.
  3. New stored value for idle rpm is shown.
  4. Press "Yes" to store a new engine speed or "No" to exit.
  5. The function is done.