SPN 3226 FMI 10

[Billdozer2]

Hey guys, so the "Time to open your wallet" light, aka Check Engine Light, came on today. Checked with Insite, SPN 3226 FMI 10 Aftertreatment Outlet NOx Sensor Circuit - Abnormal Rate of Change. After looking at the diag tree in quickserve, it seems that the outlet NOx sensor malfunctioned and needs to be replaced. Anyone else have any experience with this fault before I go digging into it later today? Truck has 442k miles and I have never replaced the NOx sensors (which I guess is pretty good). The fault also shows "Inactive" now, but I know if I just clear it, it will come back. They always do. I thought about swapping the inlet and outlet NOx sensors to see if the fault moves with the sensor. Or I could finally "fix" my truck, the right way, and be done with it. Thanks!