An apparatus and method diverts navigation guidance provided by a phone when an incoming call occurs to achieve uninterrupted route guidance. In one aspect, a communication system is integrated with the phone to divert the route guidance to a vehicle audio system or display screen when there is an incoming call. The communication system can also be integrated with a cradle, a haptic commander or a radio head unit, which can be communicatively connected with the phone and the vehicle, such that when the incoming call occurs, the route guidance information is transmitted from the phone to the vehicle audio system or display screen through the cradle, etc. Furthermore, the communication system can continuously track the vehicle location to restart the navigation system in the phone when the call is ended.