Check Engine Light Came Back On

[steelcity]

A couple of weeks ago my engine light came on and went and had it checked and the code said it was the DPFE EGR sensor, I changed it and got a new one, well afterwards I drove over 200 miles with it and the light never shut off, so I went back to the place Auto Zone it was still reading the same code.....

So the guy just erased the code and the light stayed off for 2 weeks, but now it's back on......

I know there's always a chance I got a defective sensor, but really don't feel like buying another, is there something else that can be triggering the light to come on and make this code come back..?

Thanks For Any Info
Error code P0401
2000 Ranger 3.0

 

[steelcity]

I finally got around to cleaning the connections with electrical cleaner,got the guy at the Auto Zone to clear the code...I'm hoping it doesn't come back on, but just in case is there something else I should look out for, last time he cleared the code it took around a week for it to come on again..
Thanks