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2001 Ford Crown Victoria P0402 Code: EGR Excessive Flow - Diagnosis & Fix Guide

Model: 2001 Crown Vic Fault Code: P0402 Posted: 2007-10-20 19:47

I own a 2001 Ford Crown Victoria LX (4.6L SOHC V8, single exhaust, 71,000 miles) and am currently experiencing a persistent 'Check Engine' light. The diagnostic trouble code reading is P0402 — 'EGR Excessive Flow Detected'. I've reset the code multiple times, but it returns after short drives. I took my vehicle to a mechanic who replaced both the EGR valve and EGR regulator. After this work, the same P0402 code reappeared. This has led me to suspect that either the Powertrain Control Module (PCM) is faulty or there's another underlying issue. After reviewing extensive forum discussions on P0402 in Crown Vic models, I've confirmed with my mechanic and Ford documentation that this vehicle does not have a DPFE sensor — it relies on an EGR vacuum system. However, many sources suggest the P0402 code is typically associated with a clogged or blocked EGR passage rather than a failing DPFE. I'm seeking clarity: Is the PCM malfunctioning? Could carbon buildup in the EGR passages be causing excessive flow? Are there known common fixes for this issue on 2001 Crown Vic models? I’m not inclined to replace the PCM unless absolutely necessary, as my vehicle has otherwise driven smoothly with no performance issues. Any insights or step-by-step troubleshooting tips would be greatly appreciated.

Related fault codes

P0402

Comments (6)

Anonymous 2007-10-21 18:08

It sounds like you should have consulted a technician experienced with older Crown Vic models early on — that could have saved you money on parts like the EGR valve and regulator. All Ford Crown Vics built from 1991 onward, including your 2001 model, are equipped with either a PFE or DPFE sensor. However, these codes typically show as P0401 (DPFE failure), not P0402. The Crown Vic and Marquis have their own dedicated vacuum system for EGR flow. To access the passages, remove the throttle body (four bolts) from the top of the engine. Underneath, you'll find blocked or gummed-up tubes — clean them thoroughly. If you have a scan tool, check the DPFE voltage; it should read around 1 volt (KOEI standard). If not, replace the sensor. It's typically an aluminum rectangle about 2 inches by 3 inches with two hoses attached. This fix has helped many owners with similar issues.

Anonymous 2007-10-22 11:42

If the P0402 code appears immediately upon driving, it’s more likely related to a faulty DPFE sensor than clogged EGR passages. However, if the code sets intermittently over months or years, it may point to blocked EGR ports causing excessive flow. Excessive EGR flow usually triggers this code when there's a mismatch between the PCM’s expected signal and actual readings from the DPFE — often due to a sticking or failing sensor.

Anonymous 2007-10-22 20:35

Thanks for the helpful advice! I found the correct part on AutoZone’s website. Now I just need to locate it under the hood — seems like the EGR passages are accessible with some basic tools.

Anonymous 2007-10-22 21:06

Just one question: Where exactly is the DPFE sensor located on a 2001 Crown Victoria? If it's present, can you describe its position?

Anonymous 2007-10-23 07:34

Always refer to an official service manual for accurate part locations and procedures — especially when dealing with emissions-related codes like P0402.

Anonymous 2007-10-23 18:16

To access the DPFE sensor on a 2001 Crown Vic, remove the plastic cover at the top of the engine. It's located at the rear, behind the intake manifold — a small rectangular plastic unit with two hoses and a three-wire connector.