METHOD AND SYSTEM FOR EXHAUST GAS RECIRCULATION SYSTEM DIAGNOSTICS

Methods and systems are provided for on-board diagnostics of an exhaust gas recirculation (EGR) system of an engine coupled to a hybrid vehicle. In one example, a method may include, upon receiving an engine shut-down request, prior to engine spin-down, rotating the engine at an idling speed via an electric motor and carrying out diagnostics of the EGR system. EGR diagnostics may include estimating a ratio of accumulated difference between a measured EGR flow and an EGR limit to accumulated intake air flow, over a duration of time, and indicating EGR system degradation in response to the ratio being higher than a threshold.