I did try unhooking the egr valve tube to see if relieving pressure that way would make a difference , but it still had lack of powerupon acceleration in my 2001 chevy impala

oh yes i know its you EGR valve (Exhaust Gas Recalculation)

A code P0401 most likely means one or more of the following has happened: The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced There is a blockage in the EGR (tube), most likely carbon buildup The EGR valve is faulty The EGR valve may not be opening due to a lack of vaccuum Possible Solutions In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit. Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open Clean out the EGR valve and/or tubing to remove deposits Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model) Replace the DPFE sensor (with a good quality / OEM one) Replace the EGR valve Related EGR Articles: P0400 - P0402 - P0403 - EGR System Explained

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A code P0401 most likely means one or more of the following has happened:

• The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
• There is a blockage in the EGR (tube), most likely carbon buildup
• The EGR valve is faulty
• The EGR valve may not be opening due to a lack of vaccuum

Possible SolutionsIn fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

• Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
• Clean out the EGR valve and/or tubing to remove deposits
• Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
• Replace the DPFE sensor (with a good quality / OEM one)
• Replace the EGR valve

A code P0401 likely means one ormore of the following has happened:

• The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
• There is a blockage in the EGR (tube), most likely carbon buildup
• The EGR valve is faulty
• The EGR valve may not be opening due to a lack of vacuum

PossibleSolutionsTo fix this code, it is quite commonfor people to just replace the EGR valve only to have the OBD code return. TheEGR valve is not always the culprit.

• Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticeable difference in RPM's with the EGR open
• Clean out the EGR valve and/or tubing to remove deposits
• Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
• Replace the DPFE sensor (with a good quality / OEM one)
• Replace the EGR valve

• The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
• There is a blockage in the EGR (tube), most likely carbon buildup
• The EGR valve is faulty
• The EGR valve may not be opening due to a lack of vaccuum

It is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

• Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
• Clean out the EGR valve and/or tubing to remove deposits
• Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
• Replace the DPFE sensor (with a good quality / OEM one)
• Replace the EGR valve

The EGR valve is located in the engine compartment. Its should look this

A code P0401 most likely means one or more of the following has happened:
- The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
- There is a blockage in the EGR (tube), most likely carbon buildup
- The EGR valve is faulty
- The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions: In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
- Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
- Clean out the EGR valve and/or tubing to remove deposits
- Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
- Replace the DPFE sensor (with a good quality / OEM one)
- Replace the EGR valve


Keep us updated.

A code P0401 most likely means one or more of the following has happened:
* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
* There is a blockage in the EGR (tube), most likely carbon buildup
* The EGR valve is faulty
* The EGR valve may not be opening due to a lack of vaccuum

In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
* Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
* Clean out the EGR valve and/or tubing to remove deposits
* Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
* Replace the DPFE sensor (with a good quality / OEM one)
* Replace the EGR valve

Check it and send us your advance.

• Restriction in the EGR passages, usually caused by carbon buildup
• The EGR Valve is defective
• Lack of proper vacuum or electrical signal to the EGR valve
• Malfunctioning EGR Vacuum supply solenoid
• Lack of proper EGR system feedback to the computer from the:
  
  • Manifold Absolute Pressure Sensor (MAP)
  • Differential EGR Pressure Feedback Sensor (DPFE)
  • EGR Valve Position Sensor (EVP)
  • EGR Temperature Sensor

DTC P0401 - Insufficient EGR Flow

EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.

Causes: A code P0401 most likely means one or more of the following has happened:
* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
* There is a blockage in the EGR (tube), most likely carbon buildup
* The EGR valve is faulty
* The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions: In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
* Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
* Clean out the EGR valve and/or tubing to remove deposits
* Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
* Replace the DPFE sensor (with a good quality / OEM one)
* Replace the EGR valve


DTC P1401 - Differential Pressure Feedback Electronic Sensor circuit High Voltage

I think that you need a new DPFE; first check it, you could also have something restricted. There are ports in the throttle body that can cause this as well. Check THIS LINK.

Hope helps.

A code P0401 most likely means one or more of the following has happened:

•The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
•There is a blockage in the EGR (tube), most likely carbon buildup
•The EGR valve is faulty
•The EGR valve may not be opening due to a lack of vacuum

In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

•Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticeable difference in RPM's with the EGR open
•Clean out the EGR valve and/or tubing to remove deposits
•Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
•Replace the DPFE sensor (with a good quality / OEM one)
•Replace the EGR valve

Just an idea but the Ford Mondeo ( european car ) from which I believe your engine
is taken has a habit of splitting a low pressure tube at the back
of the engine this is a relatively
cheap, easy fix. The other symptom this used to throw up was a
little more black smoke from the exhaust and a pacing/ surging from
the engine.