Welcome I'm Chris aka Moose
Below is a link to the diag steps for this code. This code indicates a switch, wiring or module issue. You mentioned the PVH losing its signal, that is normal after a period of time. The hubs get a set amount of vacuum for a certain length of time to lock in then its different to unlock. It is not like you would think vacuum always applied hubs always locked type scenario.
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I am in my upper 30's, have a wife and 2 sons. I farm, fish, hunt, build, and coach youth soccer. I work on anything with an engine, been to many schools and classes through my 12 years with the dealership to get trained and certified. I try the best I can to share what I know and or have access to with my customers. Please consider I base my questions and answers to you, solely on the information you give me since I am not there to see, smell, hear, touch, or test. I try my best to be here everyday starting at 3pm central. Rating an answer is required. Please let me know if your not pleased prior to rating or if you cannot rate me so I can try to help a different way. God Bless and have a great day.