An electrochemical detection system for determining a concentration of a gas in exhaust gases of a combustion process. The system includes an electrolyte, a reference electrode, and a sense electrode that cooperate to form an electrochemical sensor that exposes both the reference electrode and the sense electrode to the exhaust gases. The electrochemical sensor is configured to output a sensor signal indicative of a species concentration of a species gas in the exhaust gases. The sensor signal exhibits a transient error in response to a change in a reference concentration of a reference gas in the exhaust gases. The processor is configured to determine the species concentration based on the sensor signal, and to determine an estimate of the transient error based on an operating condition of the combustion process.