2008 Volvo V70 Owner's Manual - Page 153

Accessories or other objects must not be installed in front of the grille. Modification of the radar sensor could make its use illegal. The radar sensor's capacity to detect vehicles ahead is impeded: if the radar sensor is obstructed and cannot detect other vehicles, for example in heavy rain, or if snow or other objects are obscuring the radar sensor. NOTE Keep the area in front of the radar sensor clean. if the speed of vehicles ahead is significantly different from your own speed. The radar sensor has a limited field of vision. In some situations it may detect a vehicle later than expected or not detect vehicles at all. In certain situations, the radar sensor cannot detect vehicles at close quarters, for example a vehicle that suddenly enters the lanes between your vehicle and the one that the system has already detected. Small vehicles, such as motorcycles, or vehicles not driving in the center of the lane may remain undetected. In curves, the radar sensor may detect the wrong vehicle or lose a detected vehicle from view. 163 04 Comfort and driving pleasure Adaptive Cruise Control-ACC Fault tracing and actions If the message Radar blocked See manual is displayed, this means that the radar signals from the sensor have been obstructed and that a vehicle ahead cannot be detected.