Theory of Operation

WARNING: This page is about a different car, the 2011 RAM Pickup. 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 PCM. The EGR Valve motor contains three position sensors that detect to location of the EGR Valve. These sensors report the position of the valve back to the PCM over the EGR position signal wires. This diagnostic monitors the EGR solenoid driver circuits. If there is a short of open circuit detected for more than a calibrated period of time then the diagnostic will fail. 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.