2008 Mercedes CL-Class Owner's Manual - Page 465

Controls in detail Driving systems ! The operational function of the Parktronic system can be affected by dirty sensors, especially at times of snow and ice. Make sure that the area on the bumpers around the sensors is free of dirt, ice and/or slush, otherwise the Parktronic system may not function properly, see "Cleaning the Parktronic* system sensors" ( page 600). The Parktronic system deactivates at speeds over approximately 11 mph (18 km/h). At lower speeds the Parktronic system turns on again. The Parktronic system also deactivates when you set the automatic transmission to park position P or secure the vehicle in place with the electronic parking brake and switch off the engine. The Parktronic system monitors the surroundings of your vehicle with six sensors in the front bumper and four sensors in the rear bumper. i To function properly, the sensors must be free of dirt, ice, snow and slush. Clean the sensors regularly, being careful not to scratch or damage the sensors, see "Cleaning the Parktronic* system sensors" ( page 600). Range of the sensors i Interference caused by other ultrasonic signals (e.g. working jackhammers, car wash, or the air brakes of trucks) can cause the system to send erratic indications, and should be taken into consideration. The Parktronic system is an electronic parking aid with ultrasonic sensors that helps you while parking. It visually and audibly indicates the relative distance between the vehicle and an obstacle. The Parktronic system is automatically activated when you switch on the ignition, release the electronic parking brake or start the engine and engage drive position D, reverse gear R or neutral position N. 1 Sensors in the front bumper (Only visible without DISTRONIC Plus*) 464