C 15 cat running a little rough

Easy fix. Take off the valve cover and swap in a new pig tail to those actuators. Maybe 30 bucks. If like mine and code changes to a "not responding", change the solenoids. Sold in pairs at CAT for under $200.

 

That code is normally for a bad IVA solenoid or the wiring going to it. CAT ET has a test you can run to energize all 6 solenoids and run down the harness to check for shorts. Also on a lot of our C15s the plug going into the IVA solenoids get loose and backs out, they sell a new style pig tail that's way better - part# 366-9748. If you pull the rear valve cover off, the IVA solenoids are right there. Easy to change, just 4 small torx screws holding them down in the IVA housing. You can get a kit from cat that will come with a set of two solenoids. I think its part # 10R-7302.