egr valve replaced / code reset

It is more likely that the DPFE snsor has failed. To be sure, it will need to be scanned. It should read about 1 volt DC with the key on, and engine off. If it reads higher, like in the 2-4+ volt range with the key on and engine off, then P0402 will set, and a new sensor will be required. this is not an uncommon failure. Just make sure that the hoses on the sensor go back in thier right spots. They are different sizes, but they can be reversed, which will also result in faulty readings.