Each of the sensors are validated for each cycle of the prediction (every 20 seconds). Sensors that are deemed to have failed (the readings are outside the envelope or not normal for a given load condition) are flagged and not used in the prediction. In some cases, we can generate a prediction for the failed sensor and then predict the emissions.
This is not typically done by CMC; however, as we usually have redundant inputs for any critical parameters, this second level of predictions are not needed. The real-time display of the PEMS (inputs page) will show colors indicating the status of any failed sensors.