Patent ID: 8770014

Claim:
A control system for detecting a hydraulic system leak in a vehicle powertrain, comprising: a filtering module that outputs filtered pressure values by filtering a pressure signal output by a pressure sensor to remove high frequency content from said pressure signal, wherein said pressure sensor senses pressures of a fluid within a gallery of a hydraulic system of said vehicle powertrain; a pressure reading module that determines a first pressure reading based on a first one of said filtered pressure value output before a valve of said hydraulic system is actuated and that determines a second pressure reading based on a second one of said filtered pressure values output after said valve is actuated; and a comparison module that calculates a pressure ratio of said first and second pressure readings and that signals a fault condition indicative of said hydraulic system leak based on a relationship between said pressure ratio and a pressure threshold, wherein said valve controls an active fuel management event of an engine of said vehicle powertrain, said active fuel management event includes deactivating a set of cylinders of said engine, and said first one of said filtered pressure values is output before said active fuel management event and said second one of said filtered pressure values is output after said active fuel management event.