EGR Monitor

WARNING: This page is about a different car, the 2003 Dodge Intrepid, 2003 Chrysler Intrepid, 2003 Chrysler Concorde, and 2003 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.

The Powertrain Control Module (PCM) performs an on-board diagnostic check of the EGR system. The EGR monitor is used to test whether the EGR system is operating within specifications. The diagnostic check activates only during selected engine/driving conditions. When the conditions are met, the EGR is turned off (solenoid energized) and the O2 sensor compensation control is monitored. Turning off the EGR shifts the air/fuel ratio in the lean direction. The O2 sensor data should indicate an increase in the O2 concentration in the combustion chamber when the exhaust gases are no longer recirculated. While this test does not directly measure the operation of the EGR system, it can be inferred from the shift in the O2 sensor data whether the EGR system is operating correctly. Because the O2 sensor is being used, the O2 sensor test must pass its test before the EGR test. Also looks at EGR linear potentiometer for feedback.