What Predator do you have? Is it Dr Performance Stage 1 or 2 for 325/600? Does the box connect to the Fuel only, or Fuel and Map connections? I had a Stage II that did not throw any codes. They now have an adjustable 50-90hp box I see.
To see what the DTCs are, turn key to on position, then on to off three times. The actual trouble code(s) that caused the Check Engine Light will display on the OD display.