Theory of Operation
WARNING: This page is about a different car, the 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) controls the operation of the Exhaust Gas Recirculation (EGR) Airflow Control Valve. The EGR Airflow Control Valve also has a built in position sensor. The PCM monitors the EGR Airflow Control Valve Signal circuit to determine if the EGR Airflow Control Valve is moving to the proper position commanded by the PCM. The PCM will illuminate the MIL lamp after the diagnostic runs and fails in two consecutive drive cycles. The PCM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.