Howdy jaws, anyone with a 6.7L that doesn't tow every day has probably seen this code. As Vis wrote you have to get out on a highway on ramp every now and then and really get on her to create boost in order to clean the Turbo. Driving around town doesn't create boost thus not moving the sliding vane, thus not desooting the Turbo. Here's a couple of threads that will explain how the Turbo works and why it's important to create boost to keep that old P2262 away,
Cummins 6.7L VGT Exhaust Brake Operation
Cummins 6.7L Turbocharger Information