If you do a full computer scan of that truck it should include ABS. My tool will tell me if the ABS computer is not responding (on my 2007). Heck the scan tool checks computers in my seats, stereo, nav etc. etc.
Some dealerships will also scan for free. I know some repair shops that will as well.
BTW, when you replace the master cylinder, did you do a full ABS bleed? On my '07, there is a special bleeding procedure that gets the air bubbles out of the ABS unit. That requires a scan tool that can do "special tests". Auto Enginuity is the one I used. I don't think my old OTC scanner will even do it (even though it covers up to 2014 or so).