Wiring Diagram to CAN Bus needed?

Okay, well let's see what the Alternator does. I'm worried something is causing these internal PCM failures. Thats really what the P0606 code is. So, I hope the Freeze frame data has something in it.

I looked over these codes in service info again and these U0101 no comms w/ TCM, U0121 no comms w/ ABS, and U0155 no comms w/ Cluster are all being set from the PCM. So, it's not the other modules setting these codes, it's the PCM not being able to talk to those modules. Not the other way around, which is why you probably had good voltage readings at the data link connector.

These are the PCM connector with the network wires and testing in diagram 1. Check to see if theres any issues from the PCM to the rest of the modules. Let me know what you find.

Okay, are you still getting the same 4 codes as before (P0606, U0101, U0121, and U0155)? And how do you have the Fan wired up right now? This sounds like a temperature related issue. Sometimes when a PCM or any other circuit board gets a cracked solder joint, the crack won't open up until the board gets hot, causing an open circuit. The A/C compressor is a large load on the electrical system, that's why I'm curious about how exactly the Fan is wired, that way we can possibly have you back probed into a connector somewhere to monitor the voltage and catch the fault when it happens. I would do this same type of diag but with a scope on the network wires to see if the PCM comms (can bus) are dropping out at some point.

The disconnecting the negative battery cable is just resetting the PCM, some faults need to be detected a number of times (or key cycles) before any codes are set, so you're just erasing any of the fault data when you disconnect the battery.
Just looking back on the previous case folder, it has been a while, you mentioned the wires for the fan were getting hot, I assume you have the relay wired into the Ignition switch, is the load side of the relay coming from any specific fuse? So, the side of the relay that feeds power directly to the fan? I know you're planning on restoring everything to its original setup, I'm just wondering if the fans power feed is coming through the PCM in any way. If the power is coming off any fuse, which one is it? The wires getting hot means there is too much current flowing through those wires, sometimes when a fan fails, it will take out the original relay or fuse panel first, appearing to be a fault in the relay or fuse panel, when the actual failure was the fan drawing too much current, it can be deceiving. Especially when you start getting communication codes popping up as well. It's difficult to find the root cause of what is really happening. That is definitely the issue here.
So, if we can track down the circuit that the fan is on right now and see if it leads to any circuits that can't handle that much current flow. With excessive current flow, it can take a longer time until something finally burns out. Since most automotive components are designed for some heat and exposure to the elements.

Okay, good. It's been a while, glad you got it figured out.