Abstract: A system according to the principles of the present disclosure includes a diagnostic execution module and a diagnostic disabling module. The diagnostic execution module diagnoses a fault in at least one of an oxygen sensor and a catalytic converter based on input received from the oxygen sensor. The diagnostic disabling module disables the diagnosing based on at least one of a temperature of the catalytic converter and a mass flow rate of air flowing through the catalytic converter.

Abstract: A monitoring module selectively generates a request to at least one of: transition from providing rich fueling an engine to operating the engine in a fuel cutoff (FCO) state; and transition from operating the engine in the FCO state to providing rich fueling to the engine. In response to a response to the request, the monitoring module: selectively controls fueling to the engine to perform the at least one of the transitions; and selectively determines whether a fault is present in a component based on a response to the at least one of the transitions. A hybrid control module controls an electric motor of the hybrid vehicle and that selectively generates the response.

Abstract: A system according to the principles of the present disclosure includes an error period module and a sensor diagnostic module. The error period module determines an error period based on an amount of time that a first air/fuel ratio and a desired air/fuel ratio are different. A first oxygen sensor generates a first signal indicating the first air/fuel ratio. The sensor diagnostic module diagnoses a fault in the first oxygen sensor when the error period is greater than a predetermined period.

Abstract: A monitoring module selectively generates a request to at least one of: transition from providing rich fueling an engine to operating the engine in a fuel cutoff (FCO) state; and transition from operating the engine in the FCO state to providing rich fueling to the engine. In response to a response to the request, the monitoring module: selectively controls fueling to the engine to perform the at least one of the transitions; and selectively determines whether a fault is present in a component based on a response to the at least one of the transitions. A hybrid control module controls an electric motor of the hybrid vehicle and that selectively generates the response.

Abstract: A system according to the principles of the present disclosure includes an error period module and a sensor diagnostic module. The error period module determines an error period based on an amount of time that a first air/fuel ratio and a desired air/fuel ratio are different. A first oxygen sensor generates a first signal indicating the first air/fuel ratio. The sensor diagnostic module diagnoses a fault in the first oxygen sensor when the error period is greater than a predetermined period.

Abstract: A system according to the principles of the present disclosure includes a diagnostic execution module and a diagnostic disabling module. The diagnostic execution module diagnoses a fault in at least one of an oxygen sensor and a catalytic converter based on input received from the oxygen sensor. The diagnostic disabling module disables the diagnosing based on at least one of a temperature of the catalytic converter and a mass flow rate of air flowing through the catalytic converter.

Abstract: An engine control module includes an exhaust heating module, a temperature determination module, and a resistance measuring module. The exhaust heating module operates an engine at a predetermined speed to generate an exhaust gas having a predetermined temperature. The exhaust gas heats a heating element of an oxygen sensor. The temperature determination module determines, based on the predetermined speed, when the heating element is heated to the predetermined temperature. The resistance measuring module determines a resistance of the heating element when the heating element is heated to the predetermined temperature.

Abstract: An engine control module includes an exhaust heating module, a temperature determination module, and a resistance measuring module. The exhaust heating module operates an engine at a predetermined speed to generate an exhaust gas having a predetermined temperature. The exhaust gas heats a heating element of an oxygen sensor. The temperature determination module determines, based on the predetermined speed, when the heating element is heated to the predetermined temperature. The resistance measuring module determines a resistance of the heating element when the heating element is heated to the predetermined temperature.