2001 Ford Taurus PO401 and PO402 Codes: DPFE Sensor Location, EGR Cleaning, and Fix Options
Hi everyone, I'm working on my 2001 Ford Taurus with 49,000 miles, a 3.0L engine, and 12V system. The vehicle is showing persistent check engine light codes PO401 (Insufficient Diesel Oxidation Catalyst Efficiency) and PO402 (Excessive Diesel Oxidation Catalyst Efficiency). I've consulted my local Ford dealer, who recommended replacing the DPFE (Differential Pressure Feedback Emission) sensor. However, I'm unsure of its exact location—where is it installed on a 2001 Taurus? I don't have access to official service manuals, but I do have solid mechanical experience. Some forum members suggest cleaning the EGR valve, which is located behind the intake manifold. But where exactly is that valve situated? Also, would replacing spark plugs and cleaning the throttle body help improve performance or resolve these codes? I'm looking for clear, factual guidance on troubleshooting steps, sensor locations, and whether replacing the DPFE sensor will automatically clear the codes after installation. Any insights from experienced owners or mechanics would be greatly appreciated. Thanks, Brian
The DPFE sensor is typically a silver metal or black plastic box with two vacuum lines and an electrical connector featuring about three wires. It's located on the intake manifold, usually near the top of the engine. Once you have the new sensor in hand, it should be easy to spot by comparing its size and position. I recommend using an official Ford part for reliability—some parts stores can provide diagrams or photos showing exact placement. The dealer is also able to show this during a service visit. Cleaning the EGR valve is unlikely to help with these specific codes. While cleaning throttle body ports and MAF sensor isn or bad ideas, especially if not done before, it won't resolve the underlying DTCs. If you're replacing the DPFE, ensure it's the correct model for your 2001 Taurus. Check your VIN with a local Ford dealer to see if there’s an active recall related to this sensor—some models have known issues covered under recalls. Good luck and feel free to update us on progress! Jeff