i don't have a list of codes just a paper manual.

c14 - deadman closed at start up. (should clear when sw. opens)
C28 - Master switch off (Red rocker switch beside batt conn)
e110 - brake system fault. check for shorted brake coil/wiring issues.

this system is very sensitive to low battery voltage, it is worth taking the extra time and eliminating the battery as a problem. if you have another working 24 volt truck close by try using that battery in the problem truck. if not load test the battery pack.