My 2016 Laramie Ecodiesel's backup camera works intermittently. When I don't really need it, it works fine. When it would absolutely help, it goes nuts. Of course, my truck is out of warranty, so going to the dealer isn't really my best option. The service manager there implied I was a fool...
I took my truck to an independent repair guy I trust, and he said it would need a software upgrade they couldn't do. I'd need to go to a dealer. Did that, and they replaced the valve also. Expensive, but the problem went away.
I'm getting the P26AB code also. No sign of coolant leak, so I don't think the coolant bypass valve has malfunctioned. Could it be the electrical connectors? I read one comment that cleaning them fixed the problem.