System Operation
WARNING: This page is about a different car, the 1995 Mazda B4000, 1995 Mazda B3000, and 1995 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.
When engine coolant temperature is less than 131° F (55° C), EGR operation is canceled by PCM. When engine is warm, EGR operation is controlled by PCM and EGR vacuum regulator solenoid. The PCM takes input from EGR differential pressure sensor along with other sensor inputs to properly balance EGR flow. See Figure .