Engines reduced power?

[lb7diesel]

I put a very mild tow tune in a friends LMM. He was coming back from a rodeo pulling a 30' goosneck full of horses when the " Clean exhaust filter" light came on. He continued to drive it home when the 'Engine reduced power" flashed and the truck would only run 30mph. He had to drive another 50miles to get home. I loaded the stock file back in, and cannot get the truck to regen, or even not throw the reduced power code. It goes right into limp mode when started. What can i do to get this to regen? I was thinking of raising the DPF Pressures? Any ideas would be great.

Thanks
Joey