Circuit/System Description

The ECM uses the exhaust gas recirculation (EGR) position sensor to determine the position of the EGR valve. The engine control module (ECM) sends a pulse width modulated voltage signal to the EGR input signal circuit. The ECM provides a voltage return path for the sensor through the low reference circuit. A pulse width modulated signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR output signal circuit. The ECM compares the actual EGR position with the desired EGR position when the EGR valve is commanded open or closed.