POSSIBLE FIXES TO CORRECT 401 CODE ON 2001 ECLIPSE

SOURCE: code 402 0n 2001 mazda tribute

A code P0402 most likely means one or more things has happened. The DPFE (differential pressure) sensor is faulty and needs to be replaced, there is a blockage in the EGR (most likely carbon buildup) or the EGR valve may not be opening due to a lack of vaccuum.

SOURCE: 2001 Toyota camry 401 code came up. replaced the

egr position sensor. check items before you replace them, it gets expensive just guessing.

Testimonial: "thank you for the advise. and yes, it is getting expensive. "

SOURCE: 1999 FORD EXPEDITION 2WD 4.6L EGR VALVE,EGR

Remove the throttle body housing on the top of the intake, it is a 90 degree tunnel like small piece held by 4 small bolts, turn it over and look for two holes, these holes are for the EGR valve flow, they are probably plugged up with carboned crud, clean them out with the tip of a screwdriver if neccessary to remove all the crud, once its clean reinstall it and reset your check engine light, hope this helps, let me know

SOURCE: how to fix code 401 on 2001 eclipse

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

ZJ Limited

• 17989 Answers
• Posted on Jun 02, 2010

SOURCE: 2001 f 150 code po401

P0401 OBD-II Trouble Code - Insufficient EGR Flow

What does that mean?
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.

Symptoms
You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.

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

Re-Check the possible solutions and tell us news (remember rated this).