ISX15 450 Pete 386 EGR/DPF Error Code

First in advance; Thanx for those who may be able to help on this issue.

Engine is ISX15 450 2010 Model on a 2011 Pete 386.

Had a EGR Plugged several weeks ago, took it to the shop in TX, had the Cooler and Valve replaced along with all gaskets in the Exhaust.
Picked up the truck and no errors everything looked well, left out got to PA. And then got a "DPF Fuel Presser Voltage" error on the dash LED.
Now, the error went away the next day then by the end of the day it came back with an error of "See Qwners Manuel", then that went away, and the next day returned
with the error, "DPF Fuel Presser Voltage", then same display over and over back and forth.
It seems to regen more often than before, but not a constant every 15 min thing like the Volvo's are doing, it is more like 3 to 4 times during a 500-600 mile run,
Once it did it twicw with in a 300 mile run.

Is this just a simple sensor problem or does this sound like they (The Shop) didn't do something for the repair they should have, for you see, they cracked my glass fuel filter casing on the PM, and replaced my brand new shocks with out asking me, so my trust in the Pete Dealer in Sealy, TX. is not that confident.

Again Thanx for the time and consideration on this Prob.