US Patent 10301991 Systems and methods for electrically heated exhaust catalyst diagnostics

Methods and systems are provided for diagnosing an electric heater configured to increase a temperature of an exhaust catalyst positioned in an exhaust system of an engine. In one example, a method comprises diagnosing the electric heater by activating the electric heater, routing air flow from the exhaust system to an intake of the engine, and indicating the electric heater is degraded based on a test temperature in the intake being below a threshold temperature. In this way, the electric heater may be diagnosed without inclusion of costly sensors in the exhaust catalyst, and where such diagnosis conducted periodically may reduce release of undesired emissions to atmosphere.