P0401 code egr valve tube cleaning

[Chad Kennedy]

Still getting the P0401 code. I've replaced the DPFE sensor, EGR valve, gas caps, and the cracked elbow on the vacuum line. Anybody know if it would be alright to take of the pipe that goes from the egr valve down to the exhaust and spray carbon/intake cleaner down the pipe and the two tubes the DPFE sensor plugs into? Thanks for any info.



I also plan on trying another DPFE sensor, bought the last one from autozone or advance.

 

[Steve McKellop]

Non-FORD/MOTORCRAFT DPFE sensors give the F150 guys a fit. When you replace it again go OEM. On the 4.6L/5.4L F150's the passages in the intake elbow are real bad to stop up. I haven't gotten enough experience on these 4.0L SOHC motors to know if there are similar problems though. Maybe L1tech has more to offer on your problem.



edit:

Meanwhile here are the possible causes from the manual:

Vacuum supply

EGR valve stuck closed

EGR valve leaks vacuum

EGR flow path restricted

EGRVR circuit shorted to PWR

VREF open to D.P.F. EGR sensor

D.P.F. EGR sensor downstream hose off or plugged

EGRVR circuit open to PCM

VPWR open to EGRVR solenoid

D.P.F. EGR sensor hoses both off

D.P.F. EGR sensor hoses reversed

Damaged EGR orifice tube

Damaged EGRVR solenoid

Damaged PCM

 

[Todd Z]

The pipe is not that hard to remove.... BUT all the cleaner in the exhaust is not a good thing...



I would remove the pipe completly..... It is accessible by the tire and then clean away..



Todd Z

 

[scott degroot]

I have never seen the exhaust side get clogged, it's alwasy the intake side that is clogged up. trace the vacum line back from the egr valve to the egr solenoid adn make sure that it isn't broken. Next unplug the vacuum connection at the solenoid and with the engine running make sure it has vacuum there. If you have a vacuum gauge then you can hook it to where the vacuum line plugs into the egr valve adn go for a drive with the gauge tucked up under the windshield wiper. On a normal acceleration you should see about 10" on vacuum. If you don't have vacuum and the vacuum lines are ok then you either have a bad solenoid or the pcm isn't sending the signal to activate the solenoid. If you have access to a scantool that does bidirectional you can run the key on engine running self test and check the complete egr system in about 2 minutes without getting dirty if you know what you are doing. Also on a 4.0 they passage for the egr going into the intake is large enough that I have never seen one get plugged....but there is always a first.



When you replaced the DPFE did you use an OE one? Are you sure the hoses are connected correctly? It is possible there is a problem with the DPFE electricial circuit but unless you have access to a scanner it is impossible to check.