I had a bunch of codes come up on my 2019 Cummins in an all American. One was 1866.The others were for a bad EGR valve. I pulled both and everything had soot. So, I cleaned the ports blew air thru them. So, I replaced the DFN sensor and EGR.It still says my DFN sensor still doesn't read right so my amber light is still on. I clear it with Jpro and as soon as I turn the key back on it pops up as active. Tried 3 or 4 times. Ran the engine for a few minutes and still shows DFN is below or above threshold. Where do I need to look or do?
I wonder if your bus would still be covered under warranty? Also, did you try and force a regen? I've seen codes clear out by forcing the bus into a regen it normally wouldn't be doing unless warm and on highway.
Got things fixed. I took bus out for a drive. Came back light was still on. Hooked up my laptop and said I still had an 1866 sensor issue. While I was sitting there, I shut bus off and restarted looked and said the 1866 was inactive. So, I was able to regen, and it's fixed now.Thanks