derate 3712, 3714, 2976

[Rawze]

(09-19-2025 )montrose818 Wrote:  code 2976 def dosing unit temperature - data erratic, intermittent, or incorrect

codes show a wiring issue with harness to Doser unit, or a bad doser unit.

Also, it shows a nox sensor is wearing out, or is an after-garbage branded uint.

and .. when is the last time you did a full EGR tune-up so that the engine itself was not producing too much Nox and soot?.
info: https://rawze.com/forums/showthread.php?...121#pid121

[montrose818]

Mr Rawze, that is an old code, indeed from a faulty or afternarket sensor I bought off someone. I have returned it and installed one from Cummins directly, and code went inactive.

Have not done egr tuneup, we have 12 little daycabs we use and I only play mechanic when backed into a corner. Unfortunately I only have time to repair trucks when theyre broken down, as I run the business day to day and try to avoid the wrenching. This truck is located 55 miles from our mechanic and is on a 5mph derate, or I would have taken it to him already.

Doser is a genuine unit brand new, so I am down to wiring then. There were other doser codes that are now gone, but this one popped up.

I am trying to understand the logic - if the only 2 wires going to doser are to trigger it, how does temperature come into play? Trying to understand what I am working with.

Thank you so much.

[montrose818]

Question, dosing unit,.are.you referring to the one on the exhaust, or the dosing pump ?

[tree98]

I would say disregard the temperature part of that code. It's a generic code used in many cummins engines, some with the hardware to see temperature and some(2 wire doser) without.

What your looking for is a wiring issue from the ECM to the doser unit, or a bad dosing unit.

[Rawze]

(09-23-2025 )montrose818 Wrote:  Mr Rawze, that is an old code, indeed from a faulty or afternarket sensor I bought off someone. I have returned it and installed one from Cummins directly, and code went inactive.

Have not done egr tuneup, we have 12 little daycabs we use and I only play mechanic when backed into a corner.
...

THEN STOP COMPLAINING ABOUT EMISSIONS SYSTEM ISSUES!!!...

IF YOU CANNOT TAKE THE TIME TO KEEP AFTER PROPER REGULAR YEARLY MAINTENANCE OF THE ENGINE ITSELF, THEN ITS TIME TO START FINDING ANOTHER CARREER OR SOMEONE ELSE TO WORK FOR WHO ACTUALLY GIVES A DAMN!!.

[montrose818]

Update, we swapped doser pump from another truck and codes went inactive. Now I know that doser unit refers to pump and not the injector on the exhaust, which was leaking and needed replscement anway due to leaks.

Thanks all