An engine control system comprises a camshaft, a cam phaser module, a pressure sensor, and an engine control module. The camshaft is operably coupled to a crankshaft of an engine. Rotation of the camshaft operates a fuel pump in driving communication with a cam of the camshaft. The cam phaser module provides hydraulic pressure to change a rotational position of the cam about the camshaft. The pressure sensor determines a cam phaser pressure signal based on a pressure of fluid in the cam phaser module. The engine control module diagnoses a condition of the fuel pump based on the cam phaser pressure signal.