# Poor DEF Quality



## MP81 (Jul 20, 2015)

Just for reference, what are your NOx1 and NOx2 readings?


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## Burnzy (Dec 17, 2019)

NOX 1 13.3%
NOX 2 -0.6%


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## Burnzy (Dec 17, 2019)

Right after I replaced them they were NOX1 12.9% and NOX2 10.7%. Now NOX2 stays at -0.6%. It is a new sensor and I haven't driven the car since then.


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## MP81 (Jul 20, 2015)

What does the percentage relate to? I'm trying to think back to the last time I looked at Biscan, but the readings I always got were in ppm.

Did you have the countdown present when you replaced the sensor?


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## Burnzy (Dec 17, 2019)

Yes it was in countdown mode.
NOX1 325.0 PPM
NOX2 199.0 PPM
When I changed the sensor it was 
NOX1 277 PPM
NOX2 280 PPM


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## Burnzy (Dec 17, 2019)

Yes it was in countdown mode.


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## MP81 (Jul 20, 2015)

Okay - I found my old screenshot I had taken, I see how the percentage relates now.

After I replaced my sensors, on a cold start, they both read about the same, so that does look correct. Based on your before amount, your NOx2 reading didn't look off. This last time our NOx2 sensor went out (last year), it was reading _ten times higher_ than the NOx1 sensor. It also gave us a "Service Emissions Soon", not "Poor DEF Quality", for what its worth. Thankfully, it'd come and go.

The countdown, however, is not something you can get rid of - I believe the dealer has to do that, unless someone has managed to do it manually without paying them $150 to run the "diagnostic". The time before this that I replaced the NOx2 sensor (Feb of 2018), I had to take it to the dealer to run that and clear the countdown.


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## Burnzy (Dec 17, 2019)

Thank you. I was worried about the-0.6%. I guess it is time to pay Chevrolet. I was hoping it would clear itself. I have been in countdown mode before and it cleared itself. I ran the clock too low this time. I am over an hour away from the nearest dealer...Goodtimes!!!

Thank you for your help.


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## MP81 (Jul 20, 2015)

Yup - I think it needs a certain amount of time/mileage before it can self-clear. At 5mph, that's gonna take a while, haha.

Not a problem - let us know how it works out, just for reference later on.


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## sailurman (Sep 29, 2016)

Burnzy said:


> Thank you. I was worried about the-0.6%. I guess it is time to pay Chevrolet. I was hoping it would clear itself. I have been in countdown mode before and it cleared itself. I ran the clock too low this time. I am over an hour away from the nearest dealer...Goodtimes!!!
> 
> Thank you for your help.


Is that an hour at 5MPH?


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## Burnzy (Dec 17, 2019)

Yes. Usually it cleared itself before the 65 mph kicked in. This time I was on my way to work and had to keep going. 

**** emissions b.s. The only problem I have with this car is emissions problems. Using ammonia from a plastic jug to spray in my exhaust "to reduce emissions". What a p.i.t.a.


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## Burnzy (Dec 17, 2019)

sailurman said:


> Is that an hour at 5MPH?


An hour away at normal speeds. At 5mph it would be a 12hr drive...
I misread the question I meant yes it is limited to 5mph.


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## sailurman (Sep 29, 2016)

So you rolling again?


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## Burnzy (Dec 17, 2019)

No. I have been riding the motorcycle again. I have an appointment in New Orleans Thursday. I think USAA will tow it.


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## sailurman (Sep 29, 2016)

Good Luck!


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## Burnzy (Dec 17, 2019)




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## sailurman (Sep 29, 2016)

Nice....


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## e-iowa-o (Sep 2, 2015)

Hey Guys.

Burnzy.. Did you end up getting all the way down to 5 mph and it just cleared!!?

"Exhaust Fluid Quality Poor" is on my dash and I am limited to 55 mph with 35 miles away from 4 mpg (50 miles from dealer). I may have pushed it a little far, too

Before now I have been able to put it in a lower gear and run the RPMs up to like 4200 for 15 min or so and the next day the count down would go away. Not this time. 

I have never had or used any sort of scanner. I have always got by with a code reader of some kind, lately Bluetooth to Torque. Does anyone have any experience with this device? Chevrolet Cruze Diagnostic Scanner & DPF Regeneration Tool I don't know if it would benefit me. The add says it can force a regen, I don't know if that might help me

Would a bad O2, NOX, or EGT sensor be causing this? And would a scanner like this help me identify the problem?

I have about 175K on the clock. Have been in for the recalled sensors and a couple others replaced at the same time (thank you, sir. May I have another??) I hate to be at the mercy of the service department. Outside of these crazy DEF problems I have loved this car. Replaced the DEF tank heater twice, both fuel pumps (at different times), water pump and timing belt. 

I'm nervous that if I were to get the down-pipe and head in that direction that I would be lost regarding the interplay with all of these sensors. if I did and it were tuned properly could someone other than the dealer clear this countdown problem? Or would that clear out with proper tuning.

THANKS.. You folks have always had experience to share that has allowed me to keep this car rolling while handling all repairs right in my driveway.


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## Burnzy (Dec 17, 2019)

I re-tuned it.


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## Burnzy (Dec 17, 2019)

Usually "Exhaust Fluid Quality Poor" is the NOX2 sensor or the DEF injector from what I have read here. I replaced my NOX2 and tested my DEF injector but could not reset the limp mode. You can manually regenerate all day long but that doesn't reset the limp mode. If your restricted to 5mph you cannot drive it off, you have to go to the dealer....


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## Snipesy (Dec 7, 2015)

e-iowa-o said:


> Hey Guys.
> 
> Burnzy.. Did you end up getting all the way down to 5 mph and it just cleared!!?
> 
> ...


That’s some Chinese hot garbage scam. Get Gretio.


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## Burnzy (Dec 17, 2019)

If you have 35 miles left...PARK IT...then check the NOX2 & DEF injector. Then use the last 35 miles to hopefully reset the computer. 

GM Biscan can check your sensor readings.

You can pull your DEF injector and fill a syringe with DEF and feed it to the injector with plastic tubing. Use a 9 volt battery or a low voltage battery connected to the two leads on the injector...if it flows...this is probably not the problem.


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## e-iowa-o (Sep 2, 2015)

so a tune should get me past the countdown to death? I am seriously looking at the PF delete at this point. If I can get it together. I see this scan tool on line. Chevrolet Cruze Diagnostic Scanner & DPF Regeneration Tool Do you think there is any value to that if I can get it to regen could that possibly get me back on the road? this one is $300, and I 'd rather take a chance on that than take my chances with the service department.


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## e-iowa-o (Sep 2, 2015)

OK.. Thanks. I have regular freebie Torque. so I get Pro version and then get the GM Biscan app and that'll help me ck that Nox 2. can I trigger the regen with that app? Or, will it tell me if I need to?


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## e-iowa-o (Sep 2, 2015)

I dunno if it has done any harm but my slow oil pan leak has soaked the injector pretty good. and I was under it tryin to figure out how to disconnect the plug and get the DEF line off and hands froze and I quit . I'll get these apps set up and make another run at it. 

See.. you guys saved me $300 tonight!! Is Gretio an app similar to Biscan?


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## Burnzy (Dec 17, 2019)

I used biscan with the regular torque app. You can manually regen...but that will not reset the computer.

The emissions in tact programmers still require you to fix the countdown first.


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## e-iowa-o (Sep 2, 2015)

Loaded Biscan on and followed the directions to accept the PIDs.

Judging by Nox2 not moving at all between initial start up and warm up close to operating temp that it is my problem. Nox2 started at 199.0 over 0.06 and stayed there while Nox1 started the same and moved up to 330 or so when warm.

So Nox2 seems to be the culprit. Am I right?? I wonder why there is no code thrown?

I'll check back here to se if you guys concur then get one ordered. I'm hopeful that that'll get me squared away.


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## Snipesy (Dec 7, 2015)

e-iowa-o said:


> Loaded Biscan on and followed the directions to accept the PIDs.
> 
> Judging by Nox2 not moving at all between initial start up and warm up close to operating temp that it is my problem. Nox2 started at 199.0 over 0.06 and stayed there while Nox1 started the same and moved up to 330 or so when warm.
> 
> ...


NOx sensors sticking to a value is generally a sign of failure. Optimally NOx 2 should be about 70% less after warm up.

Gretio, which you get with BiScan, has a DEF Fluid Quality Test. Which takes up to 90 minutes but otherwise works similar to a service regen. Hood must be open, ECT greater than 158F. Only downside is it requires an OBDLINK device to work right.

Really the only advantage of quality test is you don’t need to drive the vehicle to clear it. It also guruantees that if there is no issue, then the warning will go away.


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## e-iowa-o (Sep 2, 2015)

Would that then verify that my DEF injector is working?


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## Snipesy (Dec 7, 2015)

e-iowa-o said:


> Would that then verify that my DEF injector is working?


If you know everything else correctly and are still getting a catalyst low performance DTC, then that’s usually a sign of a bad injector.

The injector can get clogged with junk which no DTC detects. The DEF just keeps building up in blobs until it falls off basically. Beyond manually cleaning the injector simply running the tests and a service Regen usually does a good enough job at cleaning.


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## e-iowa-o (Sep 2, 2015)

Th ODBlink is an upgrade to th bluetooth code reader I have now. Does that do away w Torque?


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## e-iowa-o (Sep 2, 2015)

I have no codes. Or, is the "Exhaust Fluid Quality Poor" my DTC?

To clarify, the ODBLINK is th plug in code reader/scanner ICan get off Amazon? If so I might get that while I wait for the Nox sensor. So I cld try to verify that injector is working before driving it.

Might the warning clear up after swapping out the Nox sensor without driving it?


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## Snipesy (Dec 7, 2015)

e-iowa-o said:


> I have no codes. Or, is the "Exhaust Fluid Quality Poor" my DTC?
> 
> To clarify, the ODBLINK is th plug in code reader/scanner ICan get off Amazon? If so I might get that while I wait for the Nox sensor. So I cld try to verify that injector is working before driving it.
> 
> Might the warning clear up after swapping out the Nox sensor without driving it?


You would want a Bluetooth one. LX, MX, or MX+.

A DTC has to execute its logic successfully and PASS for the warning to clear.

Sadly normal OBD2 tools don’t show this difference... For example in Gretio you can retrieve the “Unfinished Tests” which shows these hidden DTCs.

For the NOx sensor I don’t think idling the vehicle is enough to meet the test conditions. It must either be driven or the Fluid Quality Test needs to be done.


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## e-iowa-o (Sep 2, 2015)

I sure appreciate the guidance. I'm glad to find there's something I can use to look a little deeper into these sensor problems. So the ODBLink would serve as the interface for Torque just like Bluetooth code reader now? Or is ODBLink free standing and I'd use that instead.


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## Snipesy (Dec 7, 2015)

e-iowa-o said:


> I sure appreciate the guidance. I'm glad to find there's something I can use to look a little deeper into these sensor problems. So the ODBLink would serve as the interface for Torque just like Bluetooth code reader now? Or is ODBLink free standing and I'd use that instead.


You would download Gretio which would interface with the obdlink. Then you would just use that app. The Obdlink is backward compatible with Torque as well but it has extra features needed to do more fancy things.
You can actually download it in the mean time and play around.








Gretio - Automotive Scan Tool - Apps on Google Play


The missing pocket scan tool for GM Vehicles.




play.google.com






For SCR stuff you’d want to monitor something like this... Not sure why it’s rotated.


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## TheRealHip (Sep 1, 2014)

I'm trying to find SCR Diagnosis. How do I get there. Thanks.


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## Snipesy (Dec 7, 2015)

TheRealHip said:


> I'm trying to find SCR Diagnosis. How do I get there. Thanks.


Its a custom list. You go to the third menu -> Data View -> Click the + to make a new list -> Then you can press + again to start adding PIDs to the list. It works just like the dashboard except you can add multiple PIDs at the same time so it’s a bit faster and more convenient when you need to monitor a crap load of data.

Eventually I want to add common templates you can just pull from but I haven’t quite got there yet.


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## TheRealHip (Sep 1, 2014)

Ok thanks alot


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## e-iowa-o (Sep 2, 2015)

I got MX+ coming from Amazon. Excited to have another layer of access to detailed info. I know people can drop thousands on professional scan tools. I was considering something at Harbor Freight and this is 1/3 the cost. Plus with the familiarity that you guys have on this forum I feel a lot more confident that I can benefit from this and it wont just be a paperweight. 
[URLunfurl="true"]https://www.amazon.com/gp/product/B07JFRFJG6/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1[/URL]


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## Burnzy (Dec 17, 2019)




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## Burnzy (Dec 17, 2019)

1st tank of fuel since my new "tune".


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## Burnzy (Dec 17, 2019)

500 mile average


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## mkohan (Dec 19, 2015)

Nice!!!!


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