2009 Lincoln MKS Owner's Manual - Page 236

Driving The reverse sensing portion of the system detects obstacles up to 6 ft. (2 m) from the rear bumper with a decreased coverage area at the outer corners of the bumper, (refer to the illustration for approximate zone coverage areas). As you move closer to the obstacle, the rate of the tone increases. When the obstacle is less than 10 inches (25.0 cm) away, the tone will sound continuously. If the system detects a stationary or receding object further than 10 inches (25.0 cm) from the side of the vehicle, the tone will sound for only three seconds. Once the system detects an object approaching, the tone will sound again. While receiving a rear detection warning, the radio volume will be reduced to a predetermined level. After the warning goes away, the radio will return to the previous value. WARNING: To help avoid personal injury, please read and understand the limitations of the forward and reverse sensing system as contained in this section. Sensing is only an aid for some (generally large and fixed) objects when moving in reverse on a flat surface at "parking speeds". Traffic control systems, inclement weather, air brakes, and external motors and fans may also affect the function of the sensing system; this may include reduced performance or a false activation. WARNING: To help avoid personal injury, always use caution when in R (Reverse) and when using the sensing system. 236