DTC U1016: General Loss Of Serial Data Communications: Notes
WARNING: This page is about a different car, the 1998 Cadillac Eldorado and 1998 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
DTC U1016 will set if ignition switch is on and A/C-heater programmer has lost data communication with PCM. Diagnosis of this DTC is dependent upon other system symptoms (DTCs) present with DTC U1016.