Theory Of Operation

This diagnostic is used to check for Exhaust Gas Recirculation (EGR) flow conditions that are outside of a calibrated amount by calculating an error based on the commanded and actual EGR flow. If the error is outside of the calibrated amount for a calibrated period of time, the diagnostic fails. This algorithm is not used at areas high on the torque curve. The Powertrain Control Module (PCM) will light the MIL lamp after this monitor runs and fails twice. The PCM will turn off the MIL lamp once the diagnostic runs and passes in four consecutive drive cycles.