![]() There are actually 2 different DPFE sensors for this location, but they are both located in the same place, and look similar. It also connects to the EGR pipe via rubber hoses, but the hoses just stand straight up and they're short. On some '01 foci, the DPFE sensor is a more squarish black box with a 3-wire plug in the top and 2 hoses coming off the bottom, it sits almost on top of the EGR pipe, and is located somewhat under the air intake tube. Photo of the more common style DPFE Sensor: ![]() The 2 rubber hoses go down to the EGR Pipe, which is the 1/2" or so diameter tube you see coming off the driver's side of the exhaust manifold and going around the driver's side of the engine under the coilpack. On most Foci, the DPFE Sensor is a "Winged" Black box bolted to the firewall pretty much in the top middle, with 2 rubber hoses coming down off of it, and a 3-wire plug going into it perpendicular to the firewall. Workaround #1 only takes a few seconds but is good for making a quick diagnosis to see if the EGR system is leaning out and causing problems. However, workaround #2 listed in this article takes a while longer to perform but makes for a nice semi-permanent solution that won't cause any damage or check engine light warnings if the DPFE Sensor hasn't completely died. Of course, replacement of the bad DPFE sensor is the official recommended fix for this problem. If the stumble goes away, then your DPFE sensor is more than likely failing. If you're experencing stumble or hesitation while cruising, and think that it might be related to DPFE sensor failure, try one of the workarounds listed toward the end of this article. Note that complete DPFE sensor failure is a very slow process, and the check engine light won't come on until the DPFE sensor is pretty much done for. The DPFE sensor in the Focus is not very robust, requiring frequent (every 30k miles or sometimes less) replacement or a work around. This excessive amount of EGR combined with the air coming in via the throttle body leans out the fuel mixture, causing a lean misfire, which is the "stumble" or "hesitation" that is common as the DPFE Sensor fails. Trying to compensate, the PCM opens up the actuator too much. The DPFE Sensor is less sensitive, and the PCM thinks less recirculated gas is being burned than is actually so. When the DPFE Sensor starts failing, it gives the PCM bad information. It tells the PCM how much is flowing, and The PCM uses this reading to control the actuator. The DPFE registers the amount of pressure difference and can tell how much exhaust gas is flowing through the EGR system. There's a differential in the pressure, one tube has more pressure than the other one. When gas flows through the EGR tube, the two tubes leading to the DPFE Sensor get pressurized. Vacuum pressure opens the EGR Valve, allowing exhaust gases to be pulled from the exhaust manifold, past the DPFE tubes, then back into the intake manifold. From there, another hose goes to the EGR Valve. The actuator is on the firewall and it's an electric device controlled by the PCM that modulates how much vacuum pressure gets past it. There's a vacuum line coming off the intake manifold to the EGR actuator. DPFE means "Delta Pressure Feedback of EGR", Delta means "difference" or "change", so the DPFE Sensor reads changes in the pressure of the EGR system.It is a technique that reduces the pollutants emitted by the engine. EGR means "Exhaust Gas Recirculation", the process of sucking exhaust gases back into the engine to re-burn them.This article addresses DPFE and EGR concerns, and is a compilation of information that has been posted on the forums on the subject. The symptoms are a "stumble" and what feels like an erratic loss of power when cruising around at partial throttle. ![]() DPFE sensor failure is a fairly common problem on the Focus, and as more and more older foci get more and more miles, the failures are becoming a lot more common.
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