Technical Background
The coolant pump for the high voltage battery actively monitors its own speed and current consumption. For a given commanded speed, if the actual pump speed exceeds a defined value and the current consumption drops below a certain threshold, a dry run condition is detected. The pump communicates this to the high voltage battery control unit and fault code P0C4A00 is stored. One possible cause of this is air in the low temperature cooling system. This fault can take several hundred miles to set.
