EGR Boost Solenoid
WARNING: This page is about a different car, the 1997 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.
Remove EGR boost solenoid. Apply air pressure to port "B" of solenoid valve. See Figure . Air should flow from port "C" only. Using jumper wires, apply battery voltage to solenoid valve terminals. Apply air pressure to port "A" of solenoid valve. Air should flow from port "B" only. Replace solenoid valve as necessary.