# Exhaust Fluid Quality Poor



## dmusselm (Jan 21, 2021)

2014 with 95k miles. I replaced the nox2 sensor to fix a code. It was great for 30 miles and then it started the countdown. It also now has p249e and p22ee. I’ve topped off the DEF tank, have done a service regen, and driven 90 miles at 80mph. I have torque pro and biscan and it shows soot at 0-3g and nox1 to nox2 is about a 40% reduction with my foot on the pedal (nox1:450-500 and nox2: 250-300). I do find it odd that neither sensor ever drops below 199 ppm. I’m hoping I’m missing something simple. Is there something else that needs to be reset? It seems like the pump/ injector must be working for there to be a drop like that. Is there any other useful information I can get from the scan tools? I’m stumped!


----------



## dmusselm (Jan 21, 2021)

also, torque pro shows these tests as failed. I’m guessing that’s a torque pro bug that is misinterpreting those 16bit minimum values? Or is this a giant clue..


----------



## Detrious (Jul 5, 2017)

So it is doing something if you have some NOx drop between sensor 1 and 2. I'm not sure what % drop is normal as it isn't a % that is required, only that the NOx 2 reading be lower than whatever threshold the EPA says this engine at this speed with this HP rating etc etc etc. That being said I have seen systems on Detroit engines read 98% efficient at reducing NOx so it is possible to get close to 100%. Since it is doing some kind of work, and since you said you have topped off the system with fresh DEF (how much did you add?) I am wondering if your DEF injector is partially clogged. If you've ever done an oil change on this car it is just about a foot behind the oil drain plug, there's a hose that runs to it on the exhaust pipe. I've seen them clog up on larger engines and cause issues. If you decide to check you can take that injector off and look at the tip see if there is any dried white material. Usually it dries in clumps and will almost look like chalk. Look in the hole in the pipe too for any dried DEF. If there is any clean it with warm water and put it back together then see what you get on your NOx readings.

Also, using BiScan or Gretio apps you can reset NOx data for when you need to change sensors. I don't know if that is absolutely required to do or not though.


----------



## dmusselm (Jan 21, 2021)

Awesome advice. I will do that first thing tomorrow. Thanks.


----------



## dmusselm (Jan 21, 2021)

Not sure what did it. I drove 100 highway miles with countdown going and the light wouldn’t turn off. Then I did a service regen, topped off DEF, fresh fuel, reset all the sensors, cleaned injector. I was 60 miles and 3 trips into being limited at 65 mph when the light turned off.


----------



## Detrious (Jul 5, 2017)

How did the injector look? Any deposits?


----------



## dmusselm (Jan 21, 2021)

Detrious said:


> How did the injector look? Any deposits?


No it wasn’t bad at all. And none of the sensor data seemed to change. I don’t know what “resetting nox sensor” does but I’m half convinced that’s all I needed to do.


----------

