CCM

Yes we have PTT. Last time I ran the regen all the temps looked great. But I don't remember what the soot level is right now but I will check We are in the valley area of California so no real cold climate here. Unfortunatley we are just a small company playing in the big boys playground so we don't get a lot of help and tech support from the delaership. I hope someone could give some insite on a direction to go. I know a little bit about this stuff and have had some training in it but sometimes you just get stumped. I appreciated you giving me any info you had.

Pulled pipe and only found just a small....small amount of build up in the bottom of the inlet of the SCR. Nothing that I would call extreme. I have seen it really bad before.

I'll see what i can find. Thanks

I'm an independent shop and new to the forum. I need some tech support on a 2012 Mack MRU613 MP7 non catalyzed system. Active codes SPN 5246/FMI 0, SPN 4094/FMI 18 keep returning. I have ran the DEF nozzle pressure test,flow test and measured the amount of DEF fluid and all shows to be good. I went ahead and replaced DEF dosing nozzle and pump filter, cleared codes and unit was returned to customer but returned a week later with same issue. I looked up a few things and found that it could be a faulty NOx sensor. I replaced both Nox sensors and performed a crystal sublimation test and it allowed the codes to go inactive. released unit and again it returned with the same codes. Could this be a possible SCR catalyst failure. Any help would be appreciated.