SOURCE: 1996 Mercury Sable with a
Before replacing anything else, it's important to clear the code before determining any more repairs are necessary. You can take the car to an autoparts store that features free diagnostic tests or you can disconnect the negative battery cable for 10 minutes to clear it. If after clearing the code P0401 still appears, then it comes down to 1 of 2 problems:
An illustration of both are found at the link below:
http://www.chiltonlibrary.com/content/images/9117/images/91174p58.gif
The DPFE is located at #1
The EGR is #2
Best of luck with your Sable.
Greg
SOURCE: 1997 pontiac grand prix se has code po401. I
the egr value tubing also gets corroded with carbon. take tube off and use a wire brush to clean tubing. i talked with a mechanic and he said he has never seen an egr valve fail. most if not all egr problems are due to carbon build up in the egr tube. clean egr tube interior.
SOURCE: I have a 99 Windstar 3.8L Keep getting DTC PO401
Does the egr vavle open ? You will need to use a scanner to test the dpfe voltage when the egr valve is energized you should read around 3.5 4.00 volts. Also you could remove the vacume line from the egr valve and with the engine running you should see around 100 rpm drop in engine rpm at least this would indicate the egr valve is capable of flowing egr gases through the system to the cylinders.
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).
SOURCE: oseneck99 toyota camery got a
Recheck all the vacuum lines near the EGR solenoid. The new codes are for the EVAP emissions system. they are codes for incorrect purge flow. You may have left a vacuum line of, switched a couple of lines or forgot to plug something back in.
I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa
& DPFE voltage. There should be a noticable difference in RPM's with the EGR open39 views
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