P0402 - Keep getting this code...

[ufgators68]

I have a 2001 Ranger 4x4 ext. cab, w/ 4.0l v-6, AT and 146,000 miles, and I keep getting the code P0402. I've replaced the EGR valve, gasket and DPFE sensor. All of the hoses appear to be fine.

The CEL will go off after about 2 - 3 days and won't come back on until we go shopping. I can drive around for weeks at a time, just going to and from work, and not have the CEL come on.

Is there anything else I can try to fix the problem?

 

[YamahaWR200]

did you ever get an answer? I've been chasing a similar problem, changed the dpfe, egr, etc... I am making no head-way...

 

[Sasquatch_Ryda]

With the engine idling and you pull the vacuum line off the top of the EGR valve, is there vacuum present? If so replace the EGR Vacuum solenoid. I know mine went bad and was constantly opening the EGR when it shouldn't be.

 

[ufgators68]

did you ever get an answer? I've been chasing a similar problem, changed the dpfe, egr, etc... I am making no head-way...

Nope. The CEL hasn't flashed that code in some time. I don't know what was going on... only thing I can figure is maybe some moisture got in there, somehow.

 

[ufgators68]

And it's back again. W.T.F.

CEL came on two days ago, after my truck stuttered a little, while passing a car. Had the code read and it's P0402. Cleared it and a day later it came back on.

Any ideas? Voltage at DPFE is around 5v. The EGR valve looked clean. The hoses leading to the DPFE felt fine.

Time to change the vacuum solenoid??