I have a 2001 F150 with a 4.2 Liter. The service engine light came on. I went to Auto Zone and they said I needed a EGR Valve; which I replaced. Code P0402. The light stayed off for a day and came back on. I put another EGR Valve on it. The light came back on. Any suggestions? I am sick of this light. I have heard all kinds of reasons why this light will come on.

 

PO402-EGR- excessive flow detected
Just out of curiosity,did you disconnect the battery before replacing the EGR?

 

Dont know much about EGR but i know that those codes can be misleading...a problem with one thing can trigger a sensor in another thing that aint broken. Could the EGR be the symptom of another problem. Dont let the code send ya on a wild goose chase...and dont keep feedin it parts. But hey I know less about this stuff than any of the guys on this site...so dont take me too serious.

 

I had Auto Zone erase the code three times and I have unhooked the battery about a 100 times. The light still came back on

 

Is the truck idling normally? Does everything else seem ok when driving? It may just be the DPFE sensor. Its a silver gray rectangular metal box (approx. 2"x3") connected very near to the EGR valve just off to the left. You'll see 2 rubber hoses coming out of it and an electrical connecter.

Also, do a search on within this forum for: DPFE
and see what the other guys have to say......

 

I think the DPFE Sensor might be the cause. Does anybody know how much they cost

 

under $50.00...

 

 

It was the DPFE sensor. Thanks for all of the help. It cost 61.00. The truck is running fine and the light is off