Ford vehicles are equipped with an exhaust gas recirculation system. The EGR system controls the exhaust and routes it through the intake manifold. Within the EGR system is the differential pressure feedback exhaust sensor (DPFE). The sensor has the primary responsibility to measure and monitor the pressure within the EGR valve at any given time. The sensor relays this message to the system, which controls the amount of exhaust entering and leaving the EGR. It's important to check the DPFE if you notice your Ford is not running as smoothly or your "Check Engine" light appears.
Allow the Ford to cool if recently driven. Never perform maintenance while the engine and surrounding components are hot to touch. Open the bonnet of the vehicle.
Locate the Ford DPFE sensor. It is typically found mounted behind the intake manifold, between the firewall and engine. The sensor is directly to the left of the EGR valve and is a small, three-inch black box. The sensor has two vacuum hoses plugged into it and a three-wire harness plugged into the side.
Unplug the two vacuum hoses. Depending on the Ford model, you may have to loosen a hose clamp that secures the hose to the sensor. If so, use a flathead screwdriver to loosen the clamp, then slide it up the hose and pull the hose from the sensor. Repeat for both hoses.
Turn the ignition key to "On," bit do not start the engine. This will allow the PCM to send a signal to the sensors to begin running.
Connect the multimeter. Clip the negative lead to a grounded point, such as the negative battery terminal or a bare metal spot on the engine or frame. Clip the positive lead to the DPFE signal wire. The signal wire is the first wire to the left of the sensor.
Read the multimeter voltage. Ford DPFE sensors will measure between .45 and .55 volts. If the sensor does not measure within this range, the unit is faulty and should be replaced.