Various systems and methods are described for operating an engine system having a sensor coupled to an exhaust gas recirculation system in a motor vehicle. One example method comprises during a first operating condition, directing at least some exhaust gas from an exhaust of the engine through the exhaust gas recirculation system and past the sensor to an intake of the engine and, during a second operating condition, directing at least some fresh air through the exhaust gas recirculation system and past the sensor.