930M Aft SCR Operator Inducement issues

[Monkeywithawrench]

We have a 930M loader, PN KTG00960
Been having issues with it going into 'Safe harbor mode' (This is derate/ limp mode) since this past fall.

I keep getting codes:
E1389(2) Aft 1 SCR OPERATOR INDUCEMENT
First 9781.5 Last 9835.3 Count 3
E1389(3) Aft 1 EMISSIONS FAULT
First 9781.6 Last 9835.4 Count 4
E1389(1) Aft 1 SCR OPERATOR INDUCEMENT
First 9766.5 Last 9835.2 Count 6
E1410(2) AFT 1 CONVERSION EFFICIENCY INVALID
FIIRST 9766.5 LAST 9835.2 COUNT 6

This is when it first started:
(These are my service notes)

10/10/23 9782 Codes for SCR operator. E1389(2) and E1410(2) active events. Machine in SAFE HARBOR mode. Run After Treatment Functionality test. Codes clear…………..unknown why or what caused it.
WHAT THE f**k??!!!
Create warranty report and create product status report for review later. It's 7pm!!!

Latest incident was last night:
2/20/24 9894H Codes for SCR operator…again. E1389 (1), E1389 (2), and E1410 (2)Invalid Aftertreatment #1 SCR Conversion Efficiency. active events. Run after treatment functionality test.

60H since last reset………..need to figure this out.

DPF SOOT LOADING @ START 79.85%
FINISH 26.19% SOOT LOADING
Functionality test success………..codes cleared!!

So I'm getting between 40-60 hrs running time on the machine between it going into limp mode. Every time it goes into limp mode I just run a After Treatment Functionality test and the codes clear. There is no direct indication as to what is causing this......sensor, SCR pump/module, etc.

I've talked to the CAT Tech help line a few times. This guy is knoweledgeable ........and sadly, he is going to retire in a few weeks. He is at a loss........other than to start shotgunning parts at it. One thing that did strike me as odd..........he was VERY SUPRISED I was able to get it out of Limp Mode by running the After Treatment Functionality test. He said it usually locks the ECM out and you need to enter the SUPER SECRET CAT FACTORY PASSWORD to get it out of limp mode.

So I'm just wondering if anyone else has run into this issue and what they found the problem to be??

Nige........any guesses on this one??

 

[Nige]

Nige........any guesses on this one??

You need one of the Tier 4 guys to chime in here. This new-fangled exhuast aftertreatment gubbins is all double-Dutch to me.

I've talked to the CAT Tech help line a few times. This guy is knoweledgeable ........and sadly, he is going to retire in a few weeks. He is at a loss........other than to start shotgunning parts at it. One thing that did strike me as odd..........he was VERY SUPRISED I was able to get it out of Limp Mode by running the After Treatment Functionality test. He said it usually locks the ECM out and you need to enter the SUPER SECRET CAT FACTORY PASSWORD to get it out of limp mode.

I do know that once the alarms/warning to the operator pass a certain point the machine is locked into Limp Mode and according to the SysOp it requires Dealer ET to return it to normal operating state once the required mechanical repairs/adjustments have been performed.

 

[Monkeywithawrench]

So I've been dwelling on this today and made a few phone calls to friends in the trade.
The E1410 code for AFT 1 CONVERSION EFFICIENCY INVALID relates to the NOX sensors (inlet and outlet) not getting what they expect for readings.
I replaced the DEF injector back on 1/13/21 7490H. DEF filter hasn't been done from what I can see.

I'm going to replace DEF nozzle and the DEF filter and sock. Hopefully that will take care of the problem......we'll see.

Thanks for your input Nige.......I appreciate it.

I'll probably do this on Friday. I'll post some pics of the nozzle when I replace it. If the DEF nozzle is all gummed up and crusty......then that will be a good indication it was the nozzle.

I was joking with the owner last night while the loader was running the test.........."I'll just leave a laptop in every truck and machine, you guys can do your own resets........LOL" Been fighting with another emissions issue on a Mack MP8 dump truck.
And I'm going on vacation with the family next week!!LOL
So much to do in so little time...........

 

[ahart]

E1410 event means the nox sensors are installed in the incorrect locations. That being said, I have seen machines throw that code when the nox sensors are sending incorrect data. There are new versions of both sensors and new software that works best with them. If the NOx sensors are original, they’re due to be changed. Also, make sure there’s no DEF build up inside the SCR mixing tube from a previous injector failure. Tends to happen when they don’t shut off like they’re supposed to.

 

[Monkeywithawrench]

Thanks ahart,
Both NOX sensors are original........you are correct. I'm going to hit the cheap stuff first. DEF filter (I believe) has never been done. DEF nozzle is 3000H old?? DEF nozzle $350, DEF filter $20

NOX sensors $1000/ each.........need 2 of them. But the machine has about 10k H on it.

It's weird how running the After Treatment Functionality test clears the codes and the machine is good for a good period of time afterwards.

NOX sensors definitely not in the wrong locations............and I believe, if memory serves; one has a longer lead than the other............really tough to put them in the wrong locations.

I do see they offer REMAN NOX sensors now. How the hell do you REMAN a sensor??

So I'll do the nozzle and filter first. If it comes back, I'll hit the $2k worth of sensors.

 

[ahart]

I was confident they weren’t in the wrong locations which is why I shared the experience I’ve had there. You can do those other things but it likely won’t fix your issue. DEF filters cause low def pressure and the spray pattern/volume delivery/shut off quality can all be easily tested on the def injector. Another thing that can cause this issue is a problem with the NRS system so make sure the EGR valve is working properly.

 

[Monkeywithawrench]

I was confident they weren’t in the wrong locations which is why I shared the experience I’ve had there. You can do those other things but it likely won’t fix your issue. DEF filters cause low def pressure and the spray pattern/volume delivery/shut off quality can all be easily tested on the def injector. Another thing that can cause this issue is a problem with the NRS system so make sure the EGR valve is working properly.

I did have the tubes to the EGR differential pressure sensor get clogged with crap. Took those out and cleaned them. New pressure sensor, etc.

Good point on the def filter and pressure........still going to change it.....10k H on it. Won't hurt to take a peek at the EGR valve.......I honestly didn't even think of that.

OH HOW I DO LOVER INTERMITTENT PROBLEMS!! LOL

 

[Monkeywithawrench]

Ahart.......you ever used any REMAN NOX sensors?? Just curious........

 

[ahart]

Yes, they only recently started offering them, I usually try to order them because if they don’t have any they fill order with new part for reman price.