Abstract: A vehicle control system regulates oxides of nitrogen levels in vehicle emissions. Recirculation of exhaust gas in an engine is controlled with an exhaust gas regulator valve and/or a cam phaser. An oxides of nitrogen sensor determines the level of oxides of nitrogen levels in the exhaust gas and communicates the information to a vehicle controller. The controller determines if the oxides of nitrogen levels are within a predetermined threshold according to a lookup table. The controller adjusts the valve and/or cam phaser if the oxides of nitrogen levels are not within the threshold.