2014 780/D13 Exhuast temp/ACM/SCR, what?!

Please help if you can. 2014 780/D13

I have been getting different codes for the past week regarding, ACM then SCR fail and all kinds of threats to derate me in 165 min then 60 then goes to 135 then to 15 then bounces to 30..
then it all goes away for a few days. I have read in other posts regarding similar issues and have checked and rechecked all the wiring, the harness; checked for corrosion, The undercarriage is actually in pretty good condition overall.
I did see that the DEF doser hole (not doser itself) was clogged in crystalized def. I also found a wire going to the doser that was a little chewed through by the zip tie. I repaired that. At one point I had an open circuit for th doser but that went away before I fixed the wire.

But I am now derated to 5mph,(I removed the speed sensor so I can move if I have to).
But for me the curious thing is this: for the past week I have no exhaust temperature reading when I scroll through the gauges screen. I think its the 7th screen on gauges. It juts has to dashes --. All other gauges read a temp but nothing on the exhaust.

SO the question is: Could this signal a bad exhaust temp sensor? If so, why no fault code? Also can a faulty exhaust temp wreak this kind of havoc? Or is it really a bad Nox sensor that's causing this? But if its a Nox sensor, why no temp reading from the regular exhaust sensor? DO they work together?
(I think I saw they splice together in the harness not sure). View attachment 257782

Please anyone, before I go out and start buying parts. Thanks again.

 

Quick update, just went out to the truck and the code I have now is under the after treatment screen "204713"..If I read the DTC codes correct, this is for After treatment SCR dosing valve-Open circuit.
the Last two digits 13 is for open circuit.

So Im glad I know how to read, but what the Heck does that mean?
And still no exhaust temp reading.

 

sounds like def doser is not getting the proper power and not spraying def, sounds like you have an electrical issue with the wires somewhere check outside doser they tend to go bad rightthere.

 

I found this, right at the clip that goes to the doser. But will this me responsible for not giving me an exhaust temp reading?

 

Could be corrosion inside the wire causing the issue.

 

With the Doser? Or with the no temp reading. That's my confusion. Will one affect the other?
I am going to try and "refix" that wire. But the rest of the wire looks really good..actually the entire harness. With my old Pete all you had to do is look at it wrong and it would crumble.

 

So I bought a new exhaust temp sensor and a Def Doser. Got two cheap clamp pliers at Harbor freight to stop the coolant line from leaking.
Thank God that did it. No more codes; all gone. Except at power up it keeps reading "Acm Fail" but no codes and no longer derated to 5mph. Took her for a test drive and all was smooth. Maybe it will go away?

One thing is that I didn't realizeis that the Def doser ticks when the engine is off. It tick for a couple of minutes. The old doser didn't do that any longer, that should have been a clue I think but Im not that familiar with the D13 yet.

Thanks Nasriza correct again and also Uncleal- you can see the break in the temp wires.
Hope this helps someone else.

 

Wow, good eye.

 

Wow really good eye something is going on with acm possibly need to delete all codes and retest again, but overall it wasn't that complicated the problem always is just to find the problem.

 

Thanks..and yeah after I started her up again, I had no more warning signs. Drove from CA to CT no issues.