2006 Mercedes SL-Class Owner's Manual - Page 211

Controls in detail Driving systems Warning! G Warning! G An intermittent warning sounds and the DTR warning lamp (red) E in the speedometer dial is illuminated if the Distronic system calculates that the distance to the vehicle ahead and your vehicle's current speed indicate that Distronic will not be capable of slowing the vehicle sufficiently to maintain the preset following distance, which creates a danger of a collision. Immediately brake the vehicle to increase the distance to the vehicle in front of you. The warning sound is intended as a final caution that you have not interceded with your own braking inputs to avoid a potentially dangerous situation. Do not wait for the operation of the warning signal to intercede with your own braking, as that will result in potentially dangerous emergency braking which will not always result in an impact being avoided. Tailgating increases the risk of an accident. The Distronic brakes your vehicle with a maximum of 6.5 ft/s2 (2 m/s2). This corresponds to about 20% of the maximum deceleration ability of your vehicle. Distronic brakes the vehicle in an effort to restore the preset distance or to maintain the speed. 1 Red DTR warning lamp E 210