An exhaust treatment system for an engine includes a selective catalyst reduction (SCR) treatment module that controls a valve and an air pump to deliver air to an SCR catalyst in response to the engine turning off. An SCR loading module controls the valve and the air pump to deliver air to an exhaust manifold and controls a dosing system to deliver a dosing agent upstream of the SCR catalyst when a temperature of the SCR catalyst is less than a temperature threshold and the SCR catalyst is not saturated with ammonia.