Abstract: A diagnostic system for a vehicle includes an error module, an equivalence ratio (EQR) module, a threshold determination module, and a fault indication module. The error module determines an error value based on a difference between an amount of oxygen in exhaust measured by an exhaust gas oxygen sensor (EGO) upstream of a catalyst and an expected value of the amount. The EQR module selectively controls fuel injection based on the error value. The threshold determination module determines an error threshold based on a flow rate of fuel vapor from a vapor canister to an intake manifold of an engine. The fault indication module selectively indicates that a fault is present in the EGO sensor based on the error value and the error threshold.

Abstract: A control system according to the principles of the present disclosure includes a fuel system diagnostic module and a pump control module. The fuel system diagnostic module performs a diagnostic test on a fuel system when a vacuum pump is switched off to prevent flow through the vacuum pump and thereby seal a portion of the fuel system from an atmosphere. The vacuum pump includes a cam ring, a rotor that rotates within the cam ring, and vanes that slide into and out of slots in the rotor as the rotor rotates. The pump control module switches on the vacuum pump for a predetermined period to force the vanes out of the slots and into contact with the cam ring to seal the vacuum pump before switching off the vacuum pump for the fuel system diagnostic test.

Abstract: A diagnostic system for a vehicle includes an error module, an equivalence ratio (EQR) module, a threshold determination module, and a fault indication module. The error module determines an error value based on a difference between an amount of oxygen in exhaust measured by an exhaust gas oxygen sensor (EGO) upstream of a catalyst and an expected value of the amount. The EQR module selectively controls fuel injection based on the error value. The threshold determination module determines an error threshold based on a flow rate of fuel vapor from a vapor canister to an intake manifold of an engine. The fault indication module selectively indicates that a fault is present in the EGO sensor based on the error value and the error threshold.

Abstract: A control system according to the principles of the present disclosure includes a fuel system diagnostic module and a pump control module. The fuel system diagnostic module performs a diagnostic test on a fuel system when a vacuum pump is switched off to prevent flow through the vacuum pump and thereby seal a portion of the fuel system from an atmosphere. The vacuum pump includes a cam ring, a rotor that rotates within the cam ring, and vanes that slide into and out of slots in the rotor as the rotor rotates. The pump control module switches on the vacuum pump for a predetermined period to force the vanes out of the slots and into contact with the cam ring to seal the vacuum pump before switching off the vacuum pump for the fuel system diagnostic test.

Abstract: A fuel system diagnostic wakeup system for a vehicle includes a first control module. The first control module generates a wakeup request, powers off when the vehicle powers off, and powers on and performs a fuel system diagnostic in response to a wakeup signal while the vehicle is powered off. A second control module independent of the first control module receives the wakeup request and generates the wakeup signal after the vehicle powers off based on the wakeup request.

Abstract: A fuel system diagnostic wakeup system for a vehicle includes a first control module. The first control module generates a wakeup request, powers off when the vehicle powers off, and powers on and performs a fuel system diagnostic in response to a wakeup signal while the vehicle is powered off. A second control module independent of the first control module receives the wakeup request and generates the wakeup signal after the vehicle powers off based on the wakeup request.