QuestionI have a 98 Ford e350 5.4l engine.
P401 code keeps coming up and keeping the service engine light on.
I have replaced the EGR valve and the EGR feedback sensor and cleaned out the EGR tube and hoses.
I did all this and the P401 code keeps coming up with service light on.
Is there any thing else i can do to fix this problem cause i was told you can lose gas mileage if the EGR system is not working.
Is there any thing else i can try?
also note..... after i clear the code, i dive the van about 10to20 miles and then service engine light comes on with P401 code.
What am i missing ?
Answeryou have a broken vacuum line coming from the engine to the E.V.R. ( the valve that controls how far the E.G.R.valve opens, or a break in the line from the E.V.R. to the E.G.R. follow the vacuum line off the E.G.R. backwards. look closely at where the connection is on each end of the vacuum line where it connects to each component. you probably find a small crack where the rubber connector on either end is. if i'm not mistaken, the vacuum line that usually breaks is white.
