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Ron Z.
Ron Z., - Ford Tech -
Category: Ford
Satisfied Customers: 18958
Experience:  18+yrs experience. State Inspector & Ford Diagnostics/Repair
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1999 ford f150: v8..egr valve and looked for leaks..manifold

Customer Question

1999 ford f150 4.6l v8 p0401 code will not go away changed egr valve twice is there a sending unit or something else that could be wrong ? already changed electrical sensor next to egr valve and looked for leaks and used a shop vac to try and clean manifold at egr port. truck runs and idles great but wont pass emission test. any ideas? thanks
Submitted: 6 years ago.
Category: Ford
Expert:  Ron Z. replied 6 years ago.

Welcome to! My name is DriveFast71(Ron) and I will do my best to answer all of your questions completely and accurately.


The most common problem associated with the P0401 is a fault in the DPFE Sensor. Inspect the 2 rubber hose at the bottom of the sensor for any crack, holes, or disconnections. Inspect the electrical connector for any loose, broken or rubbed through wires. If the visual inspection checks ok, suspect a faulty DPFE Sensor. Very common fail item.


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Customer: replied 6 years ago.
just double checked wires and vac lines all look fine also i have already replaced the dpfe sensor. any other ideas or suspect areas to check out? thanks
Expert:  Ron Z. replied 6 years ago.

The only other component in the EGR system is the EGR Vacuum Solenoid Regulator. If this is not the problem either, it has to be in a vacuum line somewhere. There are only 3 components that when faulty will set a P0401 - EGR Valve, DPFE, and/or Vacuum Solenoid.