P0401 Diagnostic and Fix for Ford Explorer Sport Trac - DPFE Sensor Solution

Welcome, Ron! Check out this detailed guide on OBD2 code P0401: https://www.obd-codes.com/p0401. Note that some Ford Explorer Sport Trac models are equipped with a Differential Pressure Feedback EGR (DPFE) sensor. If your vehicle has one, it may be the actual source of the issue — consider replacing it.

This issue might still be covered under warranty depending on your model year. Could you please share the year of your Ford Explorer? That would help determine eligibility for warranty coverage.

The DPFE sensor is a common failure point in Ford Explorer Sport Tracs. Repair estimates typically range from $65 (parts) and $32.50 (labor), based on standard flat-rate pricing. These figures do not include diagnostic fees or sales tax. Source: http://autos.msn.com/research/vip/relia...delid=9589

Thanks everyone! I’ll try replacing the DPFE sensor. Is this part available at local auto parts stores, or do I need to go to a dealer? What is the part number? Thanks again, Ron.

You should be able to find the DPFE sensor at your local dealership or auto parts store. The exact part number depends on your vehicle’s model year, engine size, and build date — so it's best to confirm with a technician or parts specialist.

Thanks everyone! I replaced the DPFE sensor and have not seen the check engine light come back since. The part number is FMC 4U7Z9J460AA, priced at $35.31 including tax for models built after November 1, 2001. I spoke with a Ford parts manager who mentioned that early production units had known reliability issues with the original DPFE sensor. Note: Avoid Well’s versions — they are not compatible and perform similarly to the original part. Thanks again, Ron.

Ron Bracken wrote: Hello everyone, My Check Engine light came on. AutoZone scanned it and reported P0401 — EGR insufficient flow. I replaced the EGR valve and solenoid, but the light stayed on. After returning to AutoZone, they cleared the code. Two weeks later, it returned. I now use my own scanner and reset the code each time. Can anyone help? Thanks, Ron I had the same P0401 issue — AutoZone sold me an EGR valve too. The code came back a few days later. When I went back, they tried to replace the valve but didn’t understand that other components could cause this fault. Thanks to this forum and some online research, I learned the DPFE sensor is often at fault. I bought one and upon installation, I noticed that an air line hose from the old sensor had come loose. I reconnected it and returned to AutoZone — they refunded me for the sensor ($45). The code cleared and hasn’t returned since. AutoZone offers free code reading, even if they don't have the expertise to diagnose properly. A key takeaway: Always inspect all air lines connected to EGR components — sometimes a simple disconnect can resolve the issue. Dallas1

The DPFE sensor should be your first repair step. Under California’s Clean Air Act, parts and labor are covered for this repair. However, you must pay for diagnosis at a dealership — which costs $169 and is not covered. I paid $62 for the part and completed the replacement in under 3 minutes. I disconnected my battery to reset the system. It’s been two months now, and the vehicle runs perfectly. My 2002 Ford Explorer Sport Trac has 35,000 miles. Thanks to all of you for this helpful forum! Big Al

I just got a P0401 code at AutoZone today. I have a 1997 Explorer with a 5.0L engine. Has anyone replaced the DPFE sensor? Where is it located?

Hi — I have a 2002 Mitsubishi Galant. I'm getting a P0421 code (catalyst below threshold during warm-up). A year ago, I replaced the catalytic converter with both sensors. Now they're saying the front manifold with catalyst is needed. I checked part stores and found one priced at $849 for a Dorman Direct Manifold w/catalyst — is Dorman a reliable brand? What are some good alternatives? The store offers a 2-year warranty. Also, my car feels like it's struggling to accelerate — could this be due to the catalytic converter issue?