US Patent 10233856 Systems and methods for a variable displacement engine

Methods and systems for an engine are provided for monitoring cylinder valve deactivation of an engine. One example method includes, responsive to a request to diagnose a cylinder valve actuator of an engine during a non-fueling condition of the engine, commanding an EGR valve open and determining a first exhaust gas flow, and deactivating one or more cylinder valves and indicating cylinder valve actuator degradation when a second exhaust gas flow is not less than a threshold relative to the first exhaust gas flow.