I think the U02a3 is not related to the PMS sensor issue.
I'd do as Flan mentioned.
You have an intimate knowledge of that harness that feeds the particulate matter sensor from your previous troubleshooting and replacement of said harness. Which means you know that the power and ground circuits for the PMS are in the left harness. All three codes point to a low voltage or a bad ground for the PMS. The output voltage from the SCR relay feeds both the PMS and the DEF quality sensor. So the first place to look would be the harness connector after the splice for the DEF quality sensor, which is connector XY900A pin 5. And you are correct that XY900A is where those circuits cross over into the chassis right harness and ultimately exit at the PMS sensor connector. XY900A is located at the back of the cab, near the right frame. Seems like a big job to replace the right harness for just one wire. I would thoroughly eliminate any issues in the connector XY900A. And then I would strongly consider running a new wire to the PMS connector by itself but buried in or along the right harness.