2006 Mercedes CLK-Class Owner's Manual - Page 178

Controls in detail Automatic transmission Upshifting Briefly press button 2 on the right side of the steering wheel. The transmission will shift to the next higher gear as permitted by the shift program. This action simultaneously extends the gear range of the transmission when you are driving in the automatic program mode (C or S). Canceling gear range limit Press and hold button 2 on the right side of the steering wheel until D reappears in the multifunction display. The transmission will shift from the current gear range directly to gear range D. Shifting into optimal gear range Press and hold button 1 on the left side of the steering wheel. The transmission will automatically select the gear range suited for optimal acceleration and deceleration. This may involve shifting down one or more gears. 177