DTC P0404: EGR Open Position Performance: Description
WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
The Exhaust Gas Recirculation (EGR) valve position sensor is monitored by the Powertrain Control Module (PCM). The 5-volt reference circuit, low reference circuit and the EGR valve position signal circuit are used by the PCM to determine the EGR valve position. The PCM compares the EGR Position Sensor parameter with the Desired EGR Position parameter when the valve is commanded open or closed. If the PCM detects a calibrated difference between the EGR Position Sensor parameter and Desired EGR Position parameter for a calibrated amount of time, DTC P0404 sets.