Various systems and methods are described for controlling an engine in a
vehicle which includes an exhaust passage and an exhaust gas
recirculation system. One example method comprises adjusting an engine
operating parameter based on an exhaust gas recirculation amount, the
exhaust gas recirculation amount based on a first humidity and a second
humidity, the first humidity generated from a first humidity sensor at a
first location and the second humidity generated from a second humidity
sensor located in the exhaust passage of the engine.