DTC U1016: Loss Of Class 2 Communication With Pcm: Description
WARNING: This page is about a different car, the 1999 Buick Regal and 1999 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
Body Control Module (BCM) receives a state of health message from each module whose source ID it has learned. DTC U1016 will set when BCM does not receive a state of health message from Powertrain Control Module (PCM) after it has received other messages from PCM. SERVICE VEHICLE SOON warning indicator will come on.
A current DTC U1016 will change to a history code when BCM receives a state of health message from PCM. If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC U1016 will also clear when scan tool is used to clear codes.
NOTE:
When ignition switch is turned to RUN position with BCM disconnected, PCM-related DTC P1626 will be set. After BCM repair is completed, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.