check engine on 98 explorer sport

I recently had my check engine light come on my 98 ford explorer sport. I went to Autozone, and they pulled code p1405. I have done a good amount of searching on this code, but can't seem to find any general discussion on it.

Does anyone know what the common occurance is for this? What the usual cost is for replacement/repair? Any details would be appreciated.

This is the only thing I can find on that code, You could call a ford dealer and ask a mechanic what that code means, If you don't have one invest in a Chiltons or Hawlings manual, You could practically tear apart your car and rebuild it with one of those.
P1405
DPF-EGR Sensor Upstream Hose Off or Plugged
I am not sure if this is the correct descriptiont to find it on you explorer, but it might get you close,

The EGR valve has a control hose that goes to the intake plenum and allows the EGR valve to open at wide-open-throttle, allowing some exhaust gas to mix with the intake stream. The exhaust gas conections to the EGR valve are 3 metal tubes. One goes to the driver exhaust manifold and the others to the bottom of intake plenum on each side