PCM problem code P0601?

Hello, if it has been sitting that long I agree that most likely rodents have chewed the wire that the PCM communicates on to all the other modules, or just to the Body Control module. This setup has specific wires for scan tool communication and a single wire that communicates with all the other modules in the vehicle. I will put up a wiring diagram showing the network. But I have come across this code before and it turned out to be a burned communications trace on the Body Control Modules circuit board. That was a 2006, but the fact that the scan tool was able to communicate with the PCM, I'd be interested in seeing if they could communicate with any other modules besides the PCM and TCM (transmission computer).
I would look for this Violet wire with a yellow stripe on it, that is the PCI bus wire that goes from the PCM to the Body control module. Now if the default strategy is the same as GM, which I'll bet it is, the rest of the Modules in the vehicle will use the last known good data from the Body Control Module if the data network is down. So, focus your attention on that color wire for any chewed wiring harness. Under the dash, in the engine compartment, the highlighted wires in the 1st diagram are the wires that the scan tool uses to communicate with the PCM and TCM and the rest is through the violet/yellow wire. Where each module is labelled, it also states the location on most of them. The Body Control module is at the top, that's where I would look first, driver side end of the dash. Let us know if you find any and take a picture if possible. The CheckSum code means there is an error in reading data. It might be that the wires were chewed up and ended up shorting out, in that case, a look at the network and which modules can communicate and which are missing would be needed.

I hope they don't charge much either. If it's a good dealership, they should be able to check the network first without replacing the ECM first. Some shops will see a CheckSum code, and just through in a new module. Granted that might be the issue, but if there's open wires somewhere, they should repair them as well. Make sure to tell them it has been sitting for a while.

Here try these guys, they just preprogram the Vin number in and its plug and play. I have used them a couple times so far, it's much cheaper this way.

https://www.fs1inc.com/2001-dodge-intrepid-3-5l-engine-computer-pcm-ecm-ecu-programmed.html

After you get another ECM for the vehicle, if you want to send me the broken one, I'll see if I can fix it and send it back to you. If there is a broken solder joint or trace on the circuit board, that can be fixed. It's something I do in my spare time, there's no charge. Just leave me your email address here and Ill contact you on the side. We don't normally do this, but in certain situations I don't mind taking a look at it and repairing it if possible. If I can fix it, you'll have a spare just in case there happens to be a shorted wire in the vehicle. But get the new computer first and make sure it takes care of the code for now. I've dealt with this exact same situation before, with the same code before where other companies wouldn't even look at the circuit board because of a checksum issue. But it was just a small soldering repair. If I can't fix it, I'll let you know right away.