Porsche has the PDK transmission; Audi has the DSG transmission; and BMW has the Steptronic. To make the BMW sporty and appeal to those drivers that love a manual transmission, BMW automaker has developed an automatic transmission called the "Steptronic." At first, the Steptronic may seem confusing or difficult to use, but with a few tips and little practice, you will be able to use the Steptronic effectively. BMW is not the first automaker to make a Steptronic type of transmission.
Move the transmission knob into "D." This is Mode 1 of 3 on this transmission. Use this mode for everyday driving and if you simply want to relax and cruise in your BMW. While in D mode, the transmission will shift smoothly and quickly to give the driver the smoothest ride and the best fuel economy by shifting into the highest gear as quickly as possible.
Move your transmission knob to the left. This is Mode 2 of 3 on this transmission. This is called the DS (Drive Sport) mode. Use this mode if you are planning to accelerate fast from a traffic light or about to use a freeway on ramp. While in DS mode, the transmission will stay in each gear longer to give the driver optimum performance.
Move the transmission knob down. This is Mode 3 of 3 on this transmission. This is called "M" (manual) mode. When you move the knob down, the transmission will shift into a higher gear. Move the knob up, and the transmission will shift into a lower gear. The BMW also has paddle shifters located on the steering wheel. The right paddle is for the upshift and the left paddle is for the downshift. When shifting using M mode, you do not lift your foot off the gas. Likewise, if you accidentally do something that could damage the transmission, the computer will take over to preserve the transmission. When using M mode, make sure to use the transmission as you would a real manual. If you slow down, you need to downshift. If you do not downshift, the transmission will downshift to the appropriate gear for you. However, the transmission will not automatically upshift for you. Use M mode if you want to shift the car on your own, or if you are at the racetrack. Racers like to use the M mode to keep the car in a particular gear. Since racing is all about time, if the racer can keep the car in 2nd gear while going into a turn, he gain a slight advantage over the racer that allows the car to shift into 3rd gear and then to 2nd gear while in the turn.