REGEN ISSUE: DOSER OR OTHER?

i WILL... with that being said though... this will make the 3rd NOX sensor that this truck has required for replacement. These things suck for some reason. the first - Legitimate cause I had just purchased it... However the ones after that and the wiring harness to the sensor and now the third one.... something would be causing this. (if this is the case.)
I will definately follow up on this thread in a couple of days to advise the outcome of all of this just so those following along are advised. Still have a thought floating around in the back of my mind about the recall that was brought up by another early on Definately following up on that early tomorrow....
Will return soon.... and thanks again.

 

180613 - last six VIN

 

WELL... I certainly appreciate the heads up on the issue... It would explain the (3) seperate failures on the NOX sensor in 150k miles. I have to investigate other reasons then. That is once i find the cause as you suggested earlier.
As stated earlier I will update this post forthwith as soon as I have it all sorted out.

 

What I wound up with was a number of things. Something was sooting up the entire system. One of the sensors in the DOC wasn't producing the output while at the same time not throwing a code. I wound up going through 3 different shops, and 1 of them being warranty related replacement of the DPF before figuring out one of the input sensors were fouled up. However not before completely ruining the DOC. In the long run... the saturation of the DOC was the culprit, the DPF was the symptom, and the SCR was the casualty.
For a period of over 3 weeks of turning over loads, i was noticing the frequency of the problems mentioned earlier was being stomped on with a non stop regen required and everytime techs would hook up to the system the temps and pressures would fool them in to thinking the scr was bad, and they would dis-assemble to investigate it was fine - the cleaning of the DPF would then put off the symptoms long enough to make a few loads, and the whammo.... Finally back in February - I turned the truck over to my hometown dealership tech, and told him i didn't want the truck back until it was fixed. After I provided him with all the printouts and the symptoms explained to all you nice folks - he advised me that for some cummings engines the DOC will commit suicide in a way that's difficult to detect. Something to do with the input sensors in the DOC itself. something to do with exhaust gas pressure, and the amount of fuel being oxidized.... He told me there was a diagnostic test that should have been run that would pick up the issue that simple physical inspection of the DOC wouldn't pick up on - which is what the other dealership were doing. Just dismantlling and phyically inspecting it. It wouldn't surprize me if the DOC was the problem all along, and the only way to figure out the problem was to get home to my HomeBased Pete Dealer. - which is what i tried for sooo long. So After 4 months of trial and error, and $7,500.00 in total repair costs + other warrantied labor involved repairs... I have new components from DOC to SCR.
So if your exh inlet pressures start going unexplainalby and erratically in different directions and shutting down or failing to shut down the regen... Look at the DOC. it won't scream out in pain, it will just wimper and whine while emptying your piggy bank.
And for what it's worth... the other thing that was noticed that put me in the shop thinking DOC was the mileage dropped on the truck by 30% - less than 4.0 m.p.g Now that the problem is fixed and running out now the mileage is better than it's ever been. over 7.5 m.p.g.