What does the ford fiesta overdrive button do?

The overdrive button on the Ford Fiesta is located on the left side of the shifter, underneath the gear button. Once that button is pressed, the transmission upshifts to the highest gear possible. This button is meant to be pressed while Youre driving at a consistently high speed because it will take the strain off the engine by lowering its RPM. Basically, the overdrive allows the engine power to go right to the transmission while locking the torque converter. This will improve the performance of the vehicle and save You money on fuel at the same time.The times You dont want to use the overdrive is when Youre traveling at slower speeds. Typically when You are under 50 miles per hour or expect Youll need to accelerate quickly such as when passing another vehicle.