Patent ID: 7395837

Claim:
A pressure switch diagnostic system for an electrically variable hybrid transmission comprising: a plurality of trim valves each having a first and a second position; a plurality of pressure sensitive switches, having a high and a low logic state, each in selective fluid communication with one of said plurality of trim valves; wherein each of said plurality of pressure sensitive switches are operable to detect a change from said first to said second position or a change from said second to said first position of its respective one of said plurality of trim valves and accordingly each of said plurality of pressure switches will report one of said high or said low logic state; and at least one logic valve in selective fluid communication with at least one of said plurality of trim valves such that at least one of said plurality of pressure sensitive switches are operative to detect changes in said at least one logic valve without requiring an additional pressure sensitive switch to detect a change in position of said at least one logic valve.