P0560 troubleshooting

I have code P0560 that I’m not sure how to proceed with. I’ve seen a couple other threads that mention checking the engine ecu / ecm. The ecu fuse is good and I have 13-14 volts at the fuse terminal. Once I figured out where the ecm e7-6 pin was, I’m only getting 0.2 volts there but it is difficult to get a good connection with my multimeter. I did measure 13-14 volts on pin e7-5. While I was behind the glove box I checked the cabin filter and found a mouse nest that’s probably been there a while since I haven’t checked it in a couple years. Where should I check for wire damage causing the low voltage? I don’t see any damage from mice behind the glove box.
I also found the diagnostic instructions for this code that say to check the HV fuse and the battery ecu. The HV fuse is good and I have 13-14 volts at the fuse terminal but I have not dived into the battery ecu yet. Could a battery ecu problem cause the ecm low voltage?
Any help is much appreciated. The car does drive normal.