A system for diagnosing malfunctions in a variable valve actuation device. The system has a rocker arm assembly with first and second arms attached at a first end and a hydraulically operated latch assembly to secure the first arm to the second arm when latched. The rocker arm assembly pivots upon a hydraulic lash adjuster and includes a source of pressurized fluid connected to a hydraulic valve providing high or low pressure fluid to the hydraulically-operated latch. The latch may be operated by a remote device. A pressure transducer positioned within the hydraulic lash adjuster (HLA) is adapted to create a signal indicating fluid pressure in the HLA. A control unit coupled to the hydraulic valve and the pressure transducer is adapted to sense engine operating parameters, actuate the hydraulic valve, read the signal from the pressure transducer and identify malfunctions of the rocker arm assembly based upon the signal.