In a vehicle that includes an engine driveably connected to the vehicle wheels, an accelerator pedal, and an electric motor for transmitting power to at least some of the vehicle wheels, a method for indicating that the vehicle is operating on a grade having positive slope includes determining that displacement of the accelerator pedal is greater than a reference displacement, determining that a rate of change of the accelerator pedal displacement is greater than a reference rate of change of displacement, determining that vehicle deceleration is greater than a reference vehicle deceleration, and producing a signal representing that the vehicle is operating on a grade having positive slope.