CONTROL AND DIAGNOSTIC SYSTEMS FOR A VARIABLE CAPACITY ENGINE OIL PUMP AND AN ENGINE OIL PRESSURE SENSOR

A control system includes an oil pump module and a diagnostic module. The oil pump module, based on engine operating conditions, selectively generates a first mode request signal to initiate a first transition from operating an oil pump of an engine in one of a first pressure mode and a second pressure mode to operating the oil pump in another one of the first pressure mode and the second pressure mode. The second pressure mode is different from the first pressure mode. The diagnostic module, based on when a driver starts the engine, selectively generates a second mode request signal to initiate consecutive transitions from operating the oil pump in the second pressure mode to operating the oil pump in the first pressure mode. The diagnostic module diagnoses a pump fault when a first oil pressure change associated with the consecutive transitions is less than a first predetermined pressure change.