2006 Dodge Van engine light

One of the emissions that need to be taken care of is a gas called NOx. Usually it requires a cooling of combustion, it seems strange but exhaust is used to lower the high temperature inside your combustion chamber as it's flame front expands, pushing each piston to turn your wheels, eventually. Something is wrong with the valve that meters the amount of exhaust to be introduced. Your exhaust gas recirculation system must be tested. Each component has resistance and the valve is tested by the powertrain control module constantly after your van is hot. It may be best to bring it to a dealer or electronic engine emissions technician. Hope its ok.