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 Exhaust Gas Recirculation (EGR) Valve is opened by a motor located on top of the EGR valve. The EGR Valve is spring loaded closed. The motor electronically opens the valve and is controlled by the Powertrain Control Module (PCM). The EGR Valve motor contains three position sensors that detect to location of the EGR Valve. The three position sensors correspond to six valid sectors that the valve can be in. If the valve position skips a sector(s), a fault counter will increment by one. Once the counter equals a calibrated threshold, the rationality fault becomes active. The position sensors are integral to the EGR Valve assembly and are not serviced separately. The PCM lights the MIL lamp immediately after this diagnostic runs and fails. During this time the PCM will stop controlling the EGR valve. The default position for the valve is closed. The PCM will turn off the MIL lamp after the diagnostic runs and passes in four consecutive drive cycles.