2007 F650 stop engine light

[STROKER_T]

I got an F650 flatbed tow truck that wont get out of it's own way,only codes recieved are 68 and 111,secondary turbo inlet pressure fault and coolant level sensor fault,of which i just replaced the coolant level sensor,code stayed gone for a bit then returned....i dont see alot of these 5.9's but it acts like it's in derate mode and will barely reach 40mph....wondering if the turbo is anything like the 6.0 as far as operation,i have a known good turbo available to switch with if needed...service engine soon light and stop engine light is on and stays on when running....anybody familiar with this 68 code? thanks for your help on this

[Bruce Amacker]

I know less than nothing about 5.9s but I'd start with a basic FP and cleanliness check followed by unplugging the MAP and trying it. I "think" the Cummins turbo works considerably different than the vane type we're used to- it has a sliding sleeve inside.

 

Good Luck!