ProStar CM871 Turbo (Before Milk2)

[D_Y_F_B_A_E]

2010 International ProStar Premium
Cummins ISX CM871

I'm pretty sure my DPF is super clogged-up.
My truck won't allow me to do a regen(the regen button just blinks), I had a forced regen done at a TA. The regen failed, due to inability to get hot enough, as they put it They say it spit out an emissions code"diesel oxidation catalyst", but they have no idea what it means. I took the truck to an International dealer, and they told me it MIGHT be the turbo. They wanted to fix that and the doser injector first, to see if it was the issue.

Some guys told me to pull the truck from the shop and examine it myself, so I did. I will take some high-def picture and or video as soon as I can, if anyone would be willing to examine them and give me some advice on what repairs are actually needed, if any. And how to do any possible repairs myself. I would greatly appreciate any and all help.

I have attached the repair quote from the International Dealer ->
  Quote copy.pdf (Size: 6.63 MB / Downloads: 226)

Here's a Google Link to the repair quote-> https://drive.google.com/open?id=1IaQUih...ptCRSRq2uy