Derate and 20 psi boost due to EGR short or voltage below normal

[tree98]

What engine are we talking about here? How long has it been making 40 pounds of boost? That's quite a but too much and can cause serious engine damage. If it's in derate because of a bad EGR valve or Wiring to it, then yea demandate will straighten you out. I know a bad EGR valve will cause high boost on an 870, not sure if it would do the same on an 871 or 2250/2350. I'm assuming you don't have an 870 since they don't have an IMAP sensor.