System and method for determining an age of and controlling a selective catalytic reduction catalyst

An exhaust treatment system for exhaust gas produced by an engine includes a condition control module, a load determination module, and an age determination module. The condition control module decreases a load on a selective catalytic reduction (SCR) catalyst below a predetermined load threshold and increases exhaust gas temperature (EGT) to a predetermined temperature. The load determination module increases injection of a dosing agent into the exhaust gas and determines a load on the SCR catalyst when dosing agent is detected downstream from the SCR catalyst. The age determination module determines an age of the SCR catalyst based the determined load and predetermined loads for first and second SCR catalysts, respectively.