A system for a vehicle includes a first exhaust gas flow rate (EGF) estimation module, a second EGF estimation module, and an EGF fault detection module. The first EGF estimation module estimates a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold. The second EGF estimation module estimates a second flow rate of exhaust re-circulated back to the intake manifold based on an engine speed and an engine load. The EGF fault detection module selectively indicates a fault is present in an exhaust gas recirculation (EGR) system based on the first flow rate and the second flow rate.