Circuit Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
This diagnostic monitors the operation of the exhaust gas recirculation (EGR) valve. The powertrain control module (PCM) uses expected changes in the manifold absolute pressure (MAP) sensor readings, to evaluate the performance of the EGR system. The PCM tests the EGR system during deceleration. The PCM does this by momentarily commanding the EGR valve to open while monitoring the signal circuit of the MAP sensor. When the EGR valve is opened, the PCM will expect to see a predetermined increase in MAP. If the expected increase in MAP is not detected, the PCM suspects that the EGR valve flow is incorrect and this DTC sets.