GM Service Manual Online
For 1990-2009 cars only

Economy Mode Operation

During economy mode operation, drivers may notice increased powertrain braking after releasing the accelerator pedal. The vehicle will not coast freely when the accelerator pedal is released, but will start to gradually slow down as if the brakes were lightly applied. This feels very similar to what is experienced when releasing the accelerator pedal on a vehicle equipped with a manual transmission.

Sport Mode Operation (Where Fitted)

The sport mode was designed to simulate the performance driving of a manual transmission equipped vehicle. This means that, given certain driving conditions, the vehicle will maintain specific gears longer than a traditional automatic transmission. In addition, if a person is driving in the normal mode in fifth gear, depressing the sport button will cause an immediate 5-4 downshift that will be maintained for ten seconds. If the transmission is in any other gear when sport is engaged, no downshift will take place. No attempt should be made to change or alter these operating characteristics.