C-12 No Start

I'd get it repaired. They guy that used to work @ Pittsburgh Power has a "dyno" for them.

 

I got one from cat and programmed buy them 2 years back which came to a total of 2000 bucks. With warranty

 

Did you ever fix your truck?

 

On a 2002 Sterling I just had a similar problem crank and no start. I did not have my PC with me so I couldn't run codes, couldn't get manually through cruise control. We checked fuses, power and ground to ecm pins all good, so I went searching and checking sensors found the coolant level low and filled it up. Started right away. So any sensors that can cause a shutdown situation can cause this problem also.
Hope that helps they towed this back because the driver hadn't bothered to check the levels before taking off.
Preventive maintenance checks and services if not performed will eventually come back and bit you.