An evaporative emission canister purge actuation monitoring system (24, 124) for a motor vehicle having a vapor canister, an engine, and at least one control unit said system (24, 124) comprising: an integrated valve body (26, 126) and a cover (30, 130) mounted to said valve body (26, 126) so as to define a vent chamber (32, 132) between the cover (30, 130) and the valve body (26, 126), said cover (30, 130) having a fresh air port (34, 134) providing fluid communication between ambient air and said vent chamber (32, 132); said integrated valve body (26, 126) having a main flow passage (36, 136) and a canister port (38, 138) adapted to establish fluid communication between the vapor canister and said main flow passage (36, 136); a vacuum actuated switch (46, 146) supported by said integrated valve body (26, 126) and in electrical communication with the control unit, said switch (46, 146) including a diaphragm (60, 160) operatively supported by a retainer (62, 162) with said retainer mounted to said integrated valve body (26, 126), a flexible switch element (64, 164) and a pair of terminals (66, 166) supported by said integrated valve body (26, 126), said switch element (64, 164) responsive to movement of said diaphragm (60, 160) to connect said pair of terminals (66, 166) in response to a predetermined negative pressure in said main flow passage (36, 136) to send a signal indicative of the predetermined negative pressure to the control unit. characterized in that only two one-way umbrella valves (40,140,42,142) are intended, namely a first one-way umbrella valve (40, 140) mounted to said integrated valve body (26, 126) and responsive to a predetermined positive pressure in said main flow passage (36, 136) to control the flow of fluid from the vapor canister to the ambient air through said vent chamber (32, 132) and said fresh air port (34, 134); and a second one-way umbrella valve (42, 142) mounted to said integrated valve body (26, 126) and responsive to a predetermined negative pressure in said main flow passage (36, 136) to control the flow of ambient air through said fresh air port (34, 134) and said vent chamber (32, 132) and through said main flow passage (36, 136) and said canister port (38, 138); and an integrated valve body (26, 126) and a cover (30, 130) mounted to said valve body (26, 126) so as to define a vent chamber (32, 132) between the cover (30, 130) and the valve body (26, 126), said cover (30, 130) having a fresh air port (34, 134) providing fluid communication between ambient air and said vent chamber (32, 132); said integrated valve body (26, 126) having a main flow passage (36, 136) and a canister port (38, 138) adapted to establish fluid communication between the vapor canister and said main flow passage (36, 136); a vacuum actuated switch (46, 146) supported by said integrated valve body (26, 126) and in electrical communication with the control unit, said switch (46, 146) including a diaphragm (60, 160) operatively supported by a retainer (62, 162) with said retainer mounted to said integrated valve body (26, 126), a flexible switch element (64, 164) and a pair of terminals (66, 166) supported by said integrated valve body (26, 126), said switch element (64, 164) responsive to movement of said diaphragm (60, 160) to connect said pair of terminals (66, 166) in response to a predetermined negative pressure in said main flow passage (36, 136) to send a signal indicative of the predetermined negative pressure to the control unit. characterized in that only two one-way umbrella valves (40,140,42,142) are intended, namely a first one-way umbrella valve (40, 140) mounted to said integrated valve body (26, 126) and responsive to a predetermined positive pressure in said main flow passage (36, 136) to control the flow of fluid from the vapor canister to the ambient air through said vent chamber (32, 132) and said fresh air port (34, 134); and a second one-way umbrella valve (42, 142) mounted to said integrated valve body (26, 126) and responsive to a predetermined negative pressure in said main flow passage (36, 136) to control the flow of ambient air through said fresh air port (34, 134) and said vent chamber (32, 132) and through said main flow passage (36, 136) and said canister port (38, 138); and