I have an 02 cummins i was traveling down the interstate and all of the sudden my volt meter dropped to 0 so i pull over check everything and can't find anything so i start it up and the guage goes to about 12 so i start movin get a mile down the road and it drops out again... now i have replace the alternator still doesn't fix the problem deep cycle charge both batteries nothing now i have a ton of codes :p1682,p1693,p0252,p1689,p0215,p0236, and p0500. any help at all will be appreciated i've got no idea on what i need to do

 

you need a scan tool to check to see what your pcm voltage is the voltage regulator is
pcm computer. most likly volt reg is bad.but i would ohm the wire harness from alternator to pcm to confirm!!! low voltage to ecm on side of engine will throw lots of codes or a bad wire harness.check it out and let me know. hope this helps/72fj