2011 Mercedes GL-Class Owner's Manual - Page 172

170 Driving tips ! As the ESP® system operates automatically, the engine and the ignition must be switched off (SmartKey in position 0 or 1 in the ignition lock or Start/Stop button in position 0 or 1) while the parking brake is being tested on a brake dynamometer (maximum 10 seconds). Braking maneuvers triggered automatically by ESP® may seriously damage the brake system. If your brake system is only subjected to moderate loads, you should regularly test your brake system's function by forcefully depressing the brake pedal when driving at high speed. This also improves the brake pads' friction. G Warning Make sure that you do not endanger other road users when you apply the brakes. Make sure not to endanger any other road users when you engage the parking brake. Driving and parking Driving on wet roads Hydroplaning If water has accumulated to a certain depth on the road surface, there is a danger of hydroplaning occurring, even if: Ryou Rthe drive at low speeds tires have adequate tread depth For this reason, in the event of heavy rain or in conditions in which hydroplaning can occur you must drive in the following manner: RLower RAvoid your speed ruts RBrake carefully You can find a description of Brake Assist (BAS) on (Y page 66). Driving on flooded roads ! Do not drive through flooded areas. Check the depth of any water before driving through it. Drive slowly through standing water. Otherwise, water may enter the vehicle interior or the engine compartment. This can damage the electronic components in the engine or the automatic transmission. Water can also be drawn in by the engine's air suction nozzles and this can cause engine damage. i Set the raised vehicle level before driving through standing water. Parking brake If you drive on wet roads or dirt-covered surfaces, road salt and/or dirt could get into the parking brake. In order to prevent corrosion and a reduction in the braking power of the parking brake, observe the following: Rgently depress the parking brake from time to time before beginning the journey. Rdrive approximately 110 yd (100 m) without exceeding a speed of 12 mph (20 km/h). G Warning! While performing this procedure please assure that the vehicle is stopped before applying the parking brake. Otherwise the rear wheels could lock up. You could lose control of the vehicle and cause an accident. In addition, the vehicle's brake lights do not light up when the parking brake is engaged.