Circuit Description
WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. 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. When the ignition switch is turned to RUN position, the PCM records the EGR Learned Minimum Position. The PCM compares the EGR Learned Minimum Position parameter to the EGR Position Sensor parameter. If the PCM detects that the EGR valve is still open when the PCM is commanding the EGR valve closed, DTC P1404 sets.