DTC U2150: Loss Of Communication With Navigation Processor: Description
WARNING: This page is about a different car, the 2001 Cadillac Seville. However, it is still accessible from the selected car via links, so may be relevant.
Navigation Module (NAV) communicates with Navigation Display Head (NDH) over 2 dedicated lines. These are navigation display serial data high and low circuits. NAV does not receive a message from NDH after 3 attempts, which occurs once every 3 seconds (no communication for 9 seconds total). Display does not update of change functions or screen may become blank. Message LOSS OF COMMUNICATION WITH NAVIGATION PROCESSOR may appear on display. DTC will clear when NAV receives a response from NDH.