Finally got it figured out and fixed. There is one more ground wire, that grounds to the mounting bolt of the ECU. Loosened it up, and tightened it back down, and no more issues. Must have just had a little corrosion on the bolts loop wire connection.

Thank you all for the help!!

With battery voltage at 13.0v, it still blinks the codes with the key on/engine off.

Is there a possibility that when the mouse chewed the 02 sensor wires, that 2 of the wires could have touched each other and burnt a ground trace inside the ECU? I keep leaning towards a ground issue since there are soooo many codes.

Believe it or not, 12.3 volts is a problem. Static on a good battery should be at or above 12.6. Codes historically on these are not saved or need cleared. They are there until the problem is remedied. Load test that battery. What does it show for voltage running?

That's good to know. I will try it again this evening with a charger on it with key on/engine off, and see if that makes it quit blinking codes. And then check the voltage with it running and report back.

Thanks for the help!

That's what I was thinking as well about the grounds. I checked as much of the harness as I could see from the engine back up to the ECU. I cleaned both of the chassis ground locations. I just checked key on/engine off battery voltage, its at 12.39. That should not be causing any issues.

Once it starts, there is no check engine light. Do historic codes remove themselves from the ECU, or does a dealer have to reset it to clear them?

Thanks for the reply. I have all the plastics off that are hiding most of the wiring harness, and the front trunk bucket out so I can see the ECU and wiring. I have looked it over really good and cant see any more damage. I removed both of the chassis ground bolts, and cleaned the wiring connections (were already in great shape) and then tightened it all back up.

Good idea with low battery voltage with the engine off. I will check to see what the voltage is with key on and not running. I will put a charger on it, and turn the key on and see if it still blinks all the codes.

Thanks for the help!

I recently bought a used 2021 zforce trail 800 that only has 130 miles on it, because it ran terrible.  Someone had been digging around trying to figure out what the problem was, and I believe the owner said that he had replaced a fuel injector with no luck...

So I dragged it home, and it was blinking a check engine light while running. With the key on/engine off, It blinked out several codes about injectors, 02 sensors, speed sensor... So I started looking around and found that a mouse had chewed through the wiring on the 02 sensor closest to the seats. I fixed the wiring, fired it up, and there is no check engine light at all while its running, and it runs good now....

But, if I have key on/engine off, it still blinks out 9 different codes
0201
0202
0352
0131
0174
0138
0037
0500

But as soon as you start the engine, no check engine light at all.

Are these historic codes that just somehow need to be cleared? Or do I still have an issue that I need to track down?
I took it out on trails for a few hours, and it performed great, no check engine light at all while the engine is running. It is only blinking out the codes with key on/engine off.

Any help is appreciated!