# DEF Quality Poor Message - Countdown To Limp Mode



## ShaunH84 (Jun 22, 2021)

Hey guys - I’m currently stuck at 65 MPH with 55 next and I’m looking for help with a few codes - 2014 Chevy Cruze TDL 2.0 - 150K miles

P2463
P2002

I have ran manual regen 3 times using BiScan - it seemed to run successfully, but the DEF light remained on as well as the countdown and error codes.

Previous work:
DEF heater replaced
Sensors - So many sensors
The car has gone into limp mode at least 5 times in the past year. I have used dealers to reset and do whatever work needed done up until now, when I decided I needed a way to force regen myself with BiScan because the costs were often upward of $300 for a dealership regen.
I otherwise absolutely love this car, but man, this DEF system is the pits.


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## MP81 (Jul 20, 2015)

Interesting that it's got a DEF quality message, but the two codes relate to the DPF. 

Since you have Biscan, what do your NOx1 and NOx2 values look like?


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## Snipesy (Dec 7, 2015)

Well tldr you’ll have to use an OBDLINK MX+ and Gretio








Gretio - Automotive Scan Tool - Apps on Google Play


The missing pocket scan tool for GM Vehicles.




play.google.com





And then perform a DEF FLUID QUALITY TEST. Which is kinda like a Regen but not really.

Why is it not in Biscan? Take your pick

At the time I did not know about the importance of SCR functions.
It uses legacy technology that Google won’t support anymore. _There is seriously not enough time to explain this._
Torque Pro is slow and it felt dumb paying $30 for a $5 app.
BiScan costs money outright annnnd this is just a bad model. Gretio is free to download and try out.


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## MP81 (Jul 20, 2015)

Do you expect Gretio to be functional in Android Auto at any point in time? I know Torque was...and then it wasn't.


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## Snipesy (Dec 7, 2015)

MP81 said:


> Do you expect Gretio to be functional in Android Auto at any point in time? I know Torque was...and then it wasn't.


Google would ban me before forever for doing that. There has only been one app that ever got an exemption by Google annnnd it was Waze. And then Google bought Waze.

Bypassing Google requires root. Complete bs monopoly if you ask me. If you are rooted you can do basically whatever you want.


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## MP81 (Jul 20, 2015)

Snipesy said:


> Google would ban me before forever for doing that. There has only been one app that ever got an exemption by Google annnnd it was Waze. And then Google bought Waze.
> 
> Bypassing Google requires root. Complete bs monopoly if you ask me. If you are rooted you can do basically whatever you want.


_Supposedly _AA is supposed to allow more apps again...supposedly...

Guess it doesn't matter much at this point in time, since I haven't found a way to get AA in the car with it basically retaining all factory features and looking factory, so...


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## ShaunH84 (Jun 22, 2021)

Thanks for the advice all - I’ll get the correct link and Gretio and see what happens


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## Snipesy (Dec 7, 2015)

ShaunH84 said:


> Thanks for the advice all - I’ll get the correct link and Gretio and see what happens


You *should *get Gretio until July 2022 so as long as BiScan is also installed. If not let me know annd I can fix that.


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## sailurman (Sep 29, 2016)

ShaunH84 said:


> Thanks for the advice all - I’ll get the correct link and Gretio and see what happens


...and the survey says???


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## Snipesy (Dec 7, 2015)

sailurman said:


> ...and the survey says???


I be curious too.

Normally when people get their issue fixed they celebrate and forget about the people who helped them 

Or they come back angry cause it didn't work.


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## ShaunH84 (Jun 22, 2021)

I’ve certainly not forgotten, I just today received my MX+ and am currently attempting a test. I will keep you all updated


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## ShaunH84 (Jun 22, 2021)

SUCCESS! It took two def fluid tests, but after the second, I am officially back on the road with no countdown. I am beyond stoked about it, I have probably spent $1200 having those resets done at the dealership level. It makes me sad to know I could have been doing it myself all along.

it’s even better now that gretio is officially available on the iPhone - however, my android subscription did not carry over from my biscan purchase. How does that work?


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## Snipesy (Dec 7, 2015)

ShaunH84 said:


> SUCCESS! It took two def fluid tests, but after the second, I am officially back on the road with no countdown. I am beyond stoked about it, I have probably spent $1200 having those resets done at the dealership level. It makes me sad to know I could have been doing it myself all along.
> 
> it’s even better now that gretio is officially available on the iPhone - however, my android subscription did not carry over from my biscan purchase. How does that work?


Im working on making the subscriptions universal. That’s why the iOS has you login. Eventually even the Android will have you login as well. And then the subscription will be tied to the account you login with instead of your ‘store’ account.

There are some technical hurdles to do the transfer though.We need to somehow transfer the App Store purchases to the account.

This will likely involve a prompt saying “Would you like to transfer your subscription” since there isn’t really any way to automated it.

Anyway if you had to buy both PM me. I can fix that.


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## ShaunH84 (Jun 22, 2021)

I’m currently on the 3 day free sub on iPhone, but if it’s ok, I’ll go ahead and let it move into the subscription, and then PM you about it - or however is easiest. It’s honestly saving me so much cash, I’m happy to donate an extra $20 if it’s a pain in the butt.


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## Snipesy (Dec 7, 2015)

ShaunH84 said:


> I’m currently on the 3 day free sub on iPhone, but if it’s ok, I’ll go ahead and let it move into the subscription, and then PM you about it - or however is easiest. It’s honestly saving me so much cash, I’m happy to donate an extra $20 if it’s a pain in the butt.


It's pretty painful. But I don't want to be in the business of screwing people over.


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## usswv9696 (Nov 18, 2021)

I cannot thank you enough for the thread you posted about using the OBDLINK MX+ and Gretio!!! I had a poor DEF quality error and the countdown was on. I followed your instructions and presto....NO MORE COUNTDOWN!! I threw my hands in the air, stripped naked, and did the happy dance all the way around the block!!!!!!! I cannot even begin to tell you how much that advice saves the average Joe like me. Keep up the great work you're making a big difference!


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## bumpinalta (Feb 26, 2018)

usswv9696 said:


> I cannot thank you enough for the thread you posted about using the OBDLINK MX+ and Gretio!!! I had a poor DEF quality error and the countdown was on. I followed your instructions and presto....NO MORE COUNTDOWN!! I threw my hands in the air, stripped naked, and did the happy dance all the way around the block!!!!!!! I cannot even begin to tell you how much that advice saves the average Joe like me. Keep up the great work you're making a big difference!


Is there a link to this thread somewhere. I have the countdown running right now and need to get it fixed.

Also, do I need to look into changing my upstream NOx sensor. I have already changed out my DEF fluid. Def heater and pump were replaced ~ 2 years ago. Thanks.


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Is there a link to this thread somewhere. I have the countdown running right now and need to get it fixed.
> 
> Also, do I need to look into changing my upstream NOx sensor. I have already changed out my DEF fluid. Def heater and pump were replaced ~ 2 years ago. Thanks.


Probably referring to this
The Diesel Cruze Emissions Diagnostics Guide | Chevrolet Cruze Forums (cruzetalk.com)


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## bumpinalta (Feb 26, 2018)

OK, I need help with this. I got the Gretio app. I was working on trying to run a DEF fluid quality test, had to do a DPF regen first due to NOX readings per the instructions. After regen, NOX2 quit reading, just stayed locked at reading 99ppm. Reading other posts told me NOX 2 must be bad. Ordered a new one, and installed it. Once I started up I got a CEL for U029e which is NOX2 not reading. I reset NOX 2 sensor and cleared the CEL. NOX2 is still just reading 0ppm, CEL has not come back on though. Did a DEF quality test, NOX2 read 0 the whole time, NOX1 was 73-90ppm the whole test. It did not clear the "Service Exhaust fluid system" message or the death clock. Ideas??? suggestions???


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## bumpinalta (Feb 26, 2018)

Also is it normal for NOx 1 to take ~ 5 minutes before it reads anything after starting the engine? Also the CEL came back for U029e, NOx2 not reading.


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> OK, I need help with this. I got the Gretio app. I was working on trying to run a DEF fluid quality test, had to do a DPF regen first due to NOX readings per the instructions. After regen, NOX2 quit reading, just stayed locked at reading 99ppm. Reading other posts told me NOX 2 must be bad. Ordered a new one, and installed it. Once I started up I got a CEL for U029e which is NOX2 not reading. I reset NOX 2 sensor and cleared the CEL. NOX2 is still just reading 0ppm, CEL has not come back on though. Did a DEF quality test, NOX2 read 0 the whole time, NOX1 was 73-90ppm the whole test. It did not clear the "Service Exhaust fluid system" message or the death clock. Ideas??? suggestions???


Wiring harness failure.


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Also is it normal for NOx 1 to take ~ 5 minutes before it reads anything after starting the engine? Also the CEL came back for U029e, NOx2 not reading.


Yes. It is an O2 sensor…. Just calibrated for NOx. Needs to be warmed up.


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## bumpinalta (Feb 26, 2018)

Snipesy said:


> Wiring harness failure.


Where would I be able to find a replacement harness??


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Where would I be able to find a replacement harness??


You don’t. You use a multimeter to find the bad wires and run a new one. If it’s a connector you chop it off.

Those harnesses are very expensive. And very time consuming to replace.


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## 15cruzediesel (Sep 30, 2019)

bumpinalta said:


> Where would I be able to find a replacement harness??


First you will need to get the wire diagram for that sensor and what signals normally are present with given conditions.

Then you will need to back probe it and/or unplug it and test voltages and signals with a volt meter or an oscope to verify if communications are getting that far.

I don't know what signals would be there but I'd say at least one of them would be 12dc.

Or

Use a scan tool to observe what the sensor is and is not doing.


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## Snipesy (Dec 7, 2015)

15cruzediesel said:


> First you will need to get the wire diagram for that sensor and what signals normally are present with given conditions.
> 
> Then you will need to back probe it and/or unplug it and test voltages and signals with a volt meter or an oscope to verify if communications are getting that far.
> 
> ...


They all look like this










Pins 5 and 6 are for daisy chaining CAN. So, from Sensor 1, pins 5 and 6 go to pin 2 and 3 on sensor 2.
Pins 1 and 4 are controlled by the GPCM.


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## bumpinalta (Feb 26, 2018)

Okay. I put the old sensor back in. NOx2 went from reading 0, to reading 99 and stayed locked at 99. Gretio is telling me that reset is successful to NOx2 on either sensor. I still have the U029e code and Gretio says it's not ready to be cleared. Also fwiw the new sensor is the old part # 12641557, but the old sensor on the car has the same part #. The updated sensor #12662659 is not available anywhere and on indefinite backorder. I don't see why it would make a difference though. Also the wiring is only using 4 of the 6 pins. Pics included. Does anyone have info on where the other end of the wires is to test for continuity?


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Okay. I put the old sensor back in. NOx2 went from reading 0, to reading 99 and stayed locked at 99. Gretio is telling me that reset is successful to NOx2 on either sensor. I still have the U029e code and Gretio says it's not ready to be cleared. Also fwiw the new sensor is the old part # 12641557, but the old sensor on the car has the same part #. The updated sensor #12662659 is not available anywhere and on indefinite backorder. I don't see why it would make a difference though. Also the wiring is only using 4 of the 6 pins. Pics included. Does anyone have info on where the other end of the wires is to test for continuity?
> View attachment 295611
> 
> 
> ...



Don't test continuity. Test resistance. I know they are kind of the same thing but the "idiot light/sound" is a bad test and can make you miss a problem.

With vehicle on, follow the pic I posted. Test the connector on the vehicle harness for Nox Sensor 2.

Potential bertween between pin 1 and pin 4 should be 12V... Maybe 5V. As long as there is something you should be good. If not let us know and we can discuss next steps.


Resistance between pins 2 and 3 should be 120 ohm or 60 ohm... Depends how its setup...

If its not 120 or 60 ohm, test resistance end to end between NOx Sensor 1 to -> NOx Sensor 2. So pin 5 -> pin 2, and pin 6 -> pin 3. This should be close to 0ohms. Probably need some long ass leads for this but it can be done.

While doing all of this wiggle the connector to test for connector failures.


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## bumpinalta (Feb 26, 2018)

Snipesy, first and foremost, a sincere thank you for all the help. I'd have no hope of fixing this without your input, so thanks, its much appreciated.
Just want to clarify, on the testing you described above so I do it correctly tomorrow. First, I do ALL??? the testing with battery connected and key in "ON" position, correct? I don't want to fry something doing this.
I'm first checking for voltage on the harness for NOX2 between pins 1 and 4? Should be 5V or 12V.
Second, I'm checking ohms between pins 2 and 3, 60 or 120 ohms, if it's anything other than that, then I check NOX1 harness to NOx2 for resistance; NOX1 pin 5 to 2 on NOX2 and pin 6 to 3?
Also you said in the diagram 5,6 are for daisy chaining CAN. What is CAN?
1 and 4 controlled by GPCM, again what is GPCM?
Thanks again.


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Just want to clarify, on the testing you described above so I do it correctly tomorrow. First, I do ALL??? the testing with battery connected and key in "ON" position, correct? I don't want to fry something doing this.


When testing for that +5V or +12V (again I am not sure which it is) yes you will need key 'ON'. Otherwise, there will be no power.

For testing the CAN lines no engine can be off for that. Or on. Doesn't matter really. You're not going to fry anything.

Hope that clears that up.



bumpinalta said:


> *Second, I'm checking ohms between pins 2 and 3, 60 or 120 ohms,*


Yes



bumpinalta said:


> if it's anything other than that, then I check NOX1 harness to NOx2 for resistance; NOX1 pin 5 to 2 on NOX2 and pin 6 to 3?


No.
You'll have to forgive me I am referencing LML material (6.6L Duramax) but its the exact same system used in the Cruze.
CAN is one of the networking physical layers the truck uses... The wires that connect computers. The CAN network we are talking about is not the one on your OBD2 port. It is known as the powertrain expansion bus.
By daisy chaining I mean one module leads to the next module in the line. So in this case. ECM -> NOx 1 -> SCR -> NOx 2.









If you look at this picture you see the 2 resistors I am talking about. With the last sensor disconnected you should get 120 ohms across pins 3 and 2 of NOx sensor 2 (on both the sensor itself and the vehicle harness).

If that's not the case, we likely have wiring fault somewhere and need to find it. So, you start testing resistance across these wires.



bumpinalta said:


> 1 and 4 controlled by GPCM, again what is GPCM?
> Thanks again.


Glow plug control module. Its where the Ground and Power comes from.


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## Snipesy (Dec 7, 2015)

I'll just say it I am going to suspect that connector for NOx Sensor 2 on the vehicle's harness.

You mention previous work and there is a solid chance the dealer tech broke it.
This is not the first time I have heard of that speciific connector failing... And the good news is there is a GM pig tail
Genuine GM Connector 13579574 | eBay 

Although just chopping it off and making your own would be cheaper.


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## bumpinalta (Feb 26, 2018)

OK, test results, engine running.
DC volts pin1 to pin 4 13.0V, AC volts 27
Resistance pin 2 to pin 3 50 ohms with pos pin 2, neg pin 3; when I reverse polarity (neg pin 2, pos pin 3) resistance is ~190 ohms. My initial read is that my harness is good. What are your thoughts??? Thanks.


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> OK, test results, engine running.
> DC volts pin1 to pin 4 13.0V, AC volts 27
> Resistance pin 2 to pin 3 50 ohms with pos pin 2, neg pin 3; when I reverse polarity (neg pin 2, pos pin 3) resistance is ~190 ohms. My initial read is that my harness is good. What are your thoughts??? Thanks.


Can you take a picture of the label on NOx Sensor 1?


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## bumpinalta (Feb 26, 2018)

Here's the picture


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Here's the picture
> View attachment 295620


Well that’s the right one. Could you quick unseat the connector and spray some contact cleaner in while you’re here?

Also do that for “big blue“ which is the massive connector in front of the def tank. It has an arm you must push over.

Then see if it works.


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## bumpinalta (Feb 26, 2018)

Do you mean this one


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## bumpinalta (Feb 26, 2018)

Okay check ed and cleaned both NOx connections and all the ones on top of the def tank. No change. NOx 2 still not reading.


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## bumpinalta (Feb 26, 2018)

Okay. I put the old NOx 2 sensor back in. Gretio immediately changes the reading from 0 to 99. Why would it read differently than the new sensor if there is a wiring issue?


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Okay. I put the old NOx 2 sensor back in. Gretio immediately changes the reading from 0 to 99. Why would it read differently than the new sensor if there is a wiring issue?


It likely is getting some messages through but stops working for some unknown reason. The 0ppm is probably correct, but since there is no reliable comm, the heater never engages and thus the sensor never starts up. So, it simply reads 0 ppm.

We can attempt to clear the issue maybe get lucky:
1. Start Engine. Wait until ECT is up to temp and DEF Temp is above 23F (or its over 30F outside).
2. Run NOx Sensor 2 Reset
3. Run Reductant System Malfunction Warning Service Bay Test

That test should run for 30ish minutes. If the sensor is still locked at 99 or 0.... Ugh. There is that connector.

The next step would be to invest in something like these. So, you can observe those wires while running these tests to maybe find something. It also may be beneficial to hook a scope to the CAN lines.

But that's all time consuming. And I am still suspecting that connector. Considering it's only $50 it's probably worth replacing.

There is also the possibility that your new sensor is defective. I mean it is an older model, and it could be remanufactured or a restock. Was there anything to signify this? Lack of packaging maybe?


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## bumpinalta (Feb 26, 2018)

Okay to reset the sensor, engine must be off. So should I heat it up first then shutoff and reset? Also is the reductant system malfunction warning bay test the same as the fluid quality test? 
The only thing that makes me question the new sensor is I got it off eBay. It appears new and in the box, but like you said it is the old model. Not sure what to do about that because the new model is unavailable.


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> Okay to reset the sensor, engine must be off. So should I heat it up first then shutoff and reset? Also is the reductant system malfunction warning bay test the same as the fluid quality test?
> The only thing that makes me question the new sensor is I got it off eBay. It appears new and in the box, but like you said it is the old model. Not sure what to do about that because the new model is unavailable.


Yeah that’s fine. You can reset then warm up. Or warm up, shut off, reset, turn back on. Doesn’t matter really. I wasn’t sure if the engine had to be off for that one.


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## 15cruzediesel (Sep 30, 2019)

"There is also the possibility that your new sensor is defective. I mean it is an older model, and it could be remanufactured or a restock. Was there anything to signify this? Lack of packaging maybe?"👍

I really think you got a bum replacement sensor and your original is bad. It clearly doesn't know what to with the new sensor but does communicate with the old one.

I am guessing both sensors cause the u code your car is throwing.

I think it would be interesting to start it without the sensor being hooked up and see if it doesnt go to zero like the replacement sensor.

This is some good stuff although it sucks your having to deal with it.

I have noticed that nox2 generally takes awhile from a cold start to start giving data. Nox1 immediately chages. This makes me wonder if it hasn't been run long enough to get any data from it??


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## bumpinalta (Feb 26, 2018)

So I decided to return the sensor. It has to be bad. I don't know where I am going to find another though. My NOx 1 sensor takes about 5 minutes to read. It says -1ppm until then. NOx 2 reads 99 with my old sensor and 0 with the new and doesn't change.


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## 15cruzediesel (Sep 30, 2019)

bumpinalta said:


> So I decided to return the sensor. It has to be bad. I don't know where I am going to find another though. My NOx 1 sensor takes about 5 minutes to read. It says -1ppm until then. NOx 2 reads 99 with my old sensor and 0 with the new and doesn't change.


Somebody in here recently bought a PRC made sensor and I was hoping they would report back if it worked.

I believe this is what they bought.









1x Nox Nitrogen Oxide Sensor 12641557 For Chevrolet Cruze 2014-15 2.0L 5WK96736 | eBay


Find many great new & used options and get the best deals for 1x Nox Nitrogen Oxide Sensor 12641557 For Chevrolet Cruze 2014-15 2.0L 5WK96736 at the best online prices at eBay! Free shipping for many products!



www.ebay.com


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> So I decided to return the sensor. It has to be bad. I don't know where I am going to find another though. My NOx 1 sensor takes about 5 minutes to read. It says -1ppm until then. NOx 2 reads 99 with my old sensor and 0 with the new and doesn't change.


Yes. It is an O2 sensor, just calibrated for NOx. Which means it has a heater and needs to warm up. Usually only takes a few minutes


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## bumpinalta (Feb 26, 2018)

Snipesy, I am currently waiting for a new NOX2 sensor. On a FB Diesel Cruze forum, another member said he had the same issue as me, when replacing NOX2 he got code for not reading sensor. He said his prob ended up being DEF heater, and he reused old sensor. At any rate he recommended I try a "service bay test". Is there a way to verify temp of the DEF using sensors??? The supplemental guide states need to verify DEF is over 19 degrees C. Thanks.


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## bumpinalta (Feb 26, 2018)

Also FWIW, he said his new sensor was an original OEM, AC Delco part.


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## bumpinalta (Feb 26, 2018)

OK a bit of new info. So I ran the service bay test. during that test I noticed the warning on the DIC now stated "Service Exhaust fluid system" with the same death clock. The DTC for NOX2 never cleared and NOX2 read 0 the whole time. I swapped the old sensor back in and the DIC now shows the original "Exhaust fluid quality poor" message with the death clock. NOX 2 still reads 99 with the old sensor. I am now running service bay test with the old sensor to see what happens. Will update.


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## 15cruzediesel (Sep 30, 2019)

bumpinalta said:


> Snipesy, I am currently waiting for a new NOX2 sensor. On a FB Diesel Cruze forum, another member said he had the same issue as me, when replacing NOX2 he got code for not reading sensor. He said his prob ended up being DEF heater, and he reused old sensor. At any rate he recommended I try a "service bay test". Is there a way to verify temp of the DEF using sensors??? The supplemental guide states need to verify DEF is over 19 degrees C. Thanks.


Where did you end up buying the new sesnor you're waiting on?


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## Snipesy (Dec 7, 2015)

bumpinalta said:


> OK a bit of new info. So I ran the service bay test. during that test I noticed the warning on the DIC now stated "Service Exhaust fluid system" with the same death clock. The DTC for NOX2 never cleared and NOX2 read 0 the whole time. I swapped the old sensor back in and the DIC now shows the original "Exhaust fluid quality poor" message with the death clock. NOX 2 still reads 99 with the old sensor. I am now running service bay test with the old sensor to see what happens. Will update.





bumpinalta said:


> Snipesy, I am currently waiting for a new NOX2 sensor. On a FB Diesel Cruze forum, another member said he had the same issue as me, when replacing NOX2 he got code for not reading sensor. He said his prob ended up being DEF heater, and he reused old sensor. At any rate he recommended I try a "service bay test". Is there a way to verify temp of the DEF using sensors??? The supplemental guide states need to verify DEF is over 19 degrees C. Thanks.


There should be a “DEF Temperature” pid. You can also look at the “Inhibit Reason” for the reductant injector, if it says “DEF Frozen” then it’s too cold. Normally it will say “NOx catalyst temp” or something along those lines.


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## bumpinalta (Feb 26, 2018)

15cruzediesel said:


> Where did you end up buying the new sesnor you're waiting on?


I found a different ebay vendor with one, shipping from China, and not arriving until med Feb. I ordered it, then found a different online vendor that seemed like a US vendor and said 5 days to get it. So I cancelled the first one, paid more for the second, now it shows shipping from Szenchen province in China. No idea when I will see it. Seriously frustrating.


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## bumpinalta (Feb 26, 2018)

Also, I have read on a couple of different sites that special programming is required, "This part requires programming and/or special setup procedures. GM Service Information describes the procedures and special tools needed to ensure proper operation in the vehicle." Do you have any info on this. Gretio app has the NOx sensor "reset", which I did with the one I had ordered. Clearly didn't work. Is there another function available to tell the ECM to detect a new sensor that you are aware of??? Thanks.


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## 15cruzediesel (Sep 30, 2019)

Check out this post. Especially towards the end where he actually fixed it.









Exhaust Fluid Quality Poor, YAY


Had this pop up on me on the way home from work yesterday. Able to get home and its showing 20 miles before my first reduction. 2014 with 142k miles. It has had the Nox and DEF tank recall done last year. I took this car over from my wife about a month ago when I bought her a 4 Runner. Her...




www.cruzetalk.com


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## bumpinalta (Feb 26, 2018)

15cruzediesel said:


> Check out this post. Especially towards the end where he actually fixed it.
> 
> 
> 
> ...


I had read that thread before, but I had forgotten about his experience with NOX2 not reading until at least 10 miles of driving on a car that had already been warmed up. Still not 100% sure this was the problem I had with the new sensor that failed for me. I did the EFQT which runs the engine at 3K rpms for 30 min with the new sensor and got nothing. I don't remember EGT's from the time, but certainly all 3 were plenty hot, so it seems unlikely that the SCR system didn't get to operating temp. 
I'm still waiting on the other new sensor I ordered. I have already sent the other one back and got a refund, (couldn't wait because I only had a week to return it.) 
Like I said, I have read a few people comment that a new NOX2 sensor read zero and they couldn't get it to read. I honestly wish I had just decided to take the car for a decent drive now to see what would have happened. Right now I still have a CEL u209e for NOX2 sensor not detected which only came up after I put the new sensor in. Old sensor is still just stuck at 99, new sensor was stuck at 0.


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## bumpinalta (Feb 26, 2018)

OK...... I got the second new NOx2 sensor. I installed it. If anything it was even more of a problem. I warmed up the car and then drove about 20 miles. NOx2 read 0 the entire time, NOx1 took far longer ~10 minutes before reading. I got and tried running the service bay test, and it wouldn't run, gave me an error message and "limit out of range". A new DTC popped up in addition to the U029e for lost communication with NOx2, now has code for U02A3 for lost communication with particulate matter sensor. I thought maybe DEF was below temp so I put a heater under the tank for about 45 minutes, still wouldn't run the test. I swapped the old sensor back in, NOx2 immediately read 99 and stayed there, but now the service bay test was able to run. The DTC for NOx 2 status still showed but went from "current" status to "history", the code for the particulate sensor showed history both times. Codes will not clear though. Any ideas???? I ready to sell/ trade in the car. I've been without it for almost a month. It's really sad because the car runs perfectly and drives great. I drove it to the Rose Bowl ~1600 miles round trip just prior to all this BS. and car was awesome. Very frustrated right now.


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## bumpinalta (Feb 26, 2018)

Oh also with the new sensor in the warning message changed again from "Exhaust fluid quality poor" to "Service Exhaust fluid system". With the old sensor back in it stays reading fluid quality poor.


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## 15cruzediesel (Sep 30, 2019)

Complete guess here but are you able to put the new sensor onto the old sensors electronics by unplugging the old sensor and plugging in the new sensor? If not it would be cut and splice.

I am speculating the electronics work but the actual sensor doesn't.






How to fix and replace a faulty Nitrogen Oxide NOx sensor control unit


All of the sudden "Check Engine Light" appeared in dashboard and it's pointing to faulty nox sensor error code? Visit this guidline to fix this by yourself!




xenons4u.co.uk


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## 15cruzediesel (Sep 30, 2019)

Also have you tried to clean the original nox sensor?


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## bumpinalta (Feb 26, 2018)

Well its gone, sold it earlier today. Hopefully the guy that bought it has better luck. He definitely knows diesels better than me. He also has the option to delete if he can't fix it because he can register in a county that doesn't do emission testing. Thanks for all the help.


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## 15cruzediesel (Sep 30, 2019)

Looks like there is hope....


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## sergeantspud (Dec 5, 2014)

Okay for a 3rd highjack on this thread? It sounds like I'm late to the party, from what I gather I might be close to bumpinalta (~1600mi round trip to rose bowl from northern utah) and we could have shared parts. 

So anyways I got the DEF quality poor light on, I drive 45mi one way all highway 65mph+ to work every day. 2014 cruze, original owner, 154k miles. I had the NOX recall done early on, like sub 50k miles I think. Only recent repair is p227b which I had the dealer fix with a new ECU, that was about 1000 miles ago. I did the DEF heater around 20k miles ago.

Pulling the codes on gretio I get: P249D and P204B. We all know what P249D is but P204B appears to be: "Reductant pressure sensor performance general failure". Both of these code are in "history" though so I don't know how long ago they were present.

First thing I did was pull the DEF injector, the nozzle looks clean and was visibly wet. My assumption is that the wetness on the nozzle tip and inside the pipe is indicative that DEF is being injected. I cleaned the external surfaces and reinstalled.

Pulled up Gretio and ran a service regen, then a DEF quality test. Failed. NOX1~58ppm and NOX2~20ppm

Replaced NOX2. I was lucky enough to find a OEM one on rockauto go in stock briefly, I sort of feel bad for the other guys waiting and looking for one. Anyways I installed it, drove it around 10 miles, service regen, DEF quality test. Failed. NOX1~65ppm NOX2~16ppm

So now I'm thinking maybe my pump or injector is not functioning right. I pulled the injector and performed a DEF quantity check. It spit out about 50ml of fluid which is a pass according to the bulletin I referenced. So that would rule out my pump and injector.

Drained and filled with a new bottle of BlueDEF (date code 2/21 - a little old but I read 1 year is still okay)

Ran a DEF fluid quality again to attempt to purge the DEF lines- NOX1~68ppm NOX2~14ppm. Then I ran a service regen, and a final DEF fluid quality: NOX1~70ppm NOX~12ppm.

I feel like every time I fluid quality test it gets slightly better, but I'm worried about stressing the DPF with too many service regens. At this point I'm not sure what to do. Wondering if maybe NOX1 is under reporting, or my SCR is just getting tired. Any one have any thoughts?


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## 15cruzediesel (Sep 30, 2019)

It might not be passing because of the "history" codes.

It might just need a drive cycle completion to go back to normal IF it doesn't throw any new or previous codes during the drive cycle.


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## sergeantspud (Dec 5, 2014)

That did it!!! After work today I pulled and inspected the NOX1 sensor, didnt look too sooted up but I cleaned it with MAF cleaner and reinstalled. Then I ran a DEF quality test, failed NOX1~70ppm NOX2~19ppm. That's about the time I saw your message and wondered, maybe I should clear the codes and try again. I tried to clear them on Gretio but could not get it to go through, KOEO nor KOER. I pulled up a different scanner app and cleared that way then went back to gretio to do another DEF quality test. PASSED! NOX1~70ppm NOX2~18ppm. No more death clock countdown!

To clarify, my CEL was not on. It went on right after it started the death clock countdown but the CEL cleared about halfway home that day and has remained off since then. Now hopefully it stays cleared. I'm not sure what ended up actually being the problem, all I physically did was: NOX2 sensor replacement, DEF drain and fill, DEF injector cleaned, NOX1 sensor cleaned. I performed at least 4 service regens and probably around 7 or 8 DEF quality tests in between all those actions. Advice for anyone else, clear the codes before trying to clear the countdown with a DEF quality test!


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## 15cruzediesel (Sep 30, 2019)

sergeantspud said:


> That did it!!! After work today I pulled and inspected the NOX1 sensor, didnt look too sooted up but I cleaned it with MAF cleaner and reinstalled. Then I ran a DEF quality test, failed NOX1~70ppm NOX2~19ppm. That's about the time I saw your message and wondered, maybe I should clear the codes and try again. I tried to clear them on Gretio but could not get it to go through, KOEO nor KOER. I pulled up a different scanner app and cleared that way then went back to gretio to do another DEF quality test. PASSED! NOX1~70ppm NOX2~18ppm. No more death clock countdown!
> 
> To clarify, my CEL was not on. It went on right after it started the death clock countdown but the CEL cleared about halfway home that day and has remained off since then. Now hopefully it stays cleared. I'm not sure what ended up actually being the problem, all I physically did was: NOX2 sensor replacement, DEF drain and fill, DEF injector cleaned, NOX1 sensor cleaned. I performed at least 4 service regens and probably around 7 or 8 DEF quality tests in between all those actions. Advice for anyone else, clear the codes before trying to clear the countdown with a DEF quality test!


Sweet. Nice to hear a success story for a change.


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## Snipesy (Dec 7, 2015)

sergeantspud said:


> That did it!!! After work today I pulled and inspected the NOX1 sensor, didnt look too sooted up but I cleaned it with MAF cleaner and reinstalled. Then I ran a DEF quality test, failed NOX1~70ppm NOX2~19ppm. That's about the time I saw your message and wondered, maybe I should clear the codes and try again. I tried to clear them on Gretio but could not get it to go through, KOEO nor KOER. I pulled up a different scanner app and cleared that way then went back to gretio to do another DEF quality test. PASSED! NOX1~70ppm NOX2~18ppm. No more death clock countdown!
> 
> To clarify, my CEL was not on. It went on right after it started the death clock countdown but the CEL cleared about halfway home that day and has remained off since then. Now hopefully it stays cleared. I'm not sure what ended up actually being the problem, all I physically did was: NOX2 sensor replacement, DEF drain and fill, DEF injector cleaned, NOX1 sensor cleaned. I performed at least 4 service regens and probably around 7 or 8 DEF quality tests in between all those actions. Advice for anyone else, clear the codes before trying to clear the countdown with a DEF quality test!


These newer vehicles are very temperamental on when you can clear codes. That’s why it says stuff like “Conditions not Correct.”

Generally if you power off and then on again (no start) your chances are better.

Just fair warning good chance the other tool did not clear codes. Most tools just send the message but do not check if clearing actually worked.

Worse case scenario just drive the vehicle a lot. 10 minute drives. Drive cycles clear codes.


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## BDCCruze (Jul 12, 2017)

@Snipesy - Do these cars do DEF quality testing on their own periodically? I can't imagine the intention from GM is that you must have it done at a dealer. Shouldn't the cars 'self heal' after a false positive code? Is draining the DEF and refilling and driving it until death clock countdown goes away enough?


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## Snipesy (Dec 7, 2015)

BDCCruze said:


> @Snipesy - Do these cars do DEF quality testing on their own periodically? I can't imagine the intention from GM is that you must have it done at a dealer. Shouldn't the cars 'self heal' after a false positive code? Is draining the DEF and refilling and driving it until death clock countdown goes away enough?


During normal highway driving yes.

The advantage of the quality test is it’s stationary. And after 4mph it’s basicially your only option.


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## 15cruzediesel (Sep 30, 2019)

BDCCruze said:


> @Snipesy - Do these cars do DEF quality testing on their own periodically? I can't imagine the intention from GM is that you must have it done at a dealer. Shouldn't the cars 'self heal' after a false positive code? Is draining the DEF and refilling and driving it until death clock countdown goes away enough?


Anytime nox1 and nox2 are working correctly it is doing a def quality test.

Let's say you put "bad" def in the car:

It will command the appropriate amount of def to control nox emissions. 

If at some point nox emissions are excessive and can't be controlled, it would throw a def quality poor. 

This is assuming everything is working correctly, since the amount of def needed isn't working.

The car would be correct and the def fluid isn't effective in this scenario.

I know when you look at block diagrams for solving diesel emissions problems, they all contain a concern for tampering when it comes to def.


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## Snipesy (Dec 7, 2015)

15cruzediesel said:


> The car would be correct and the def fluid isn't effective in this scenario.
> 
> I know when you look at block diagrams for solving diesel emissions problems, they all contain a concern for tampering when it comes to def.


Those we’re written back in like 2011 where they wrongly thought DEF Quality would be important. And that people would try and fake the system.

In reality it’s insanely rare. And DEF QUALITY errors means the SCR is just not working as effective as it should be. That could be a sensor, injector issue, etc… but it’s rarely because of def quality.

This is because said error comes from monitoring NOx sensor 1 and 2. And thus it’s purely a measure of SCR efficiency. Not DEF quality.

GM did change this. And now new diesels use a dedicated quality sensor. But not on the Gen 1.


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## 15cruzediesel (Sep 30, 2019)

Snipesy said:


> Those we’re written back in like 2011 where they wrongly thought DEF Quality would be important. And that people would try and fake the system.
> 
> In reality it’s insanely rare. And DEF QUALITY errors means the SCR is just not working as effective as it should be. That could be a sensor, injector issue, etc… but it’s rarely because of def quality.
> 
> ...


Sorta.

You have to ask yourself what an scr needs to work and it most be fresh or it won't work.

Without the oxidizing agent the scr is worthless to meet the emissions requirements the government imposes.

I agree it is probably rare to be bad.

Sadly stealerships have made a ton of money charging people to flush and refill def tanks.


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## TyGeR (Oct 24, 2016)

Hello guys, 2 years after I resolved my issue (the other post someone one linked) Im back to having the same issue. This time I have a P20EE code, I replaced the tank heater again with no luck, then replaced the upstream Nox1 sensor, (toe P20EE code) it cleared the fault for 30 mins or so but came back. The tablet I use with my USB cable took a dump so Im debating on getting another tablet an see if the USB cable will work with the Gretio app or buy the MX+ OBD tool and use it bluetooth with my phone. The guide that Snipesy put together looks like really good info. Once I get either a new tablet or the MX+ tool I'll start working on my car again an hope I can get everything cleared up!

On a side note, its funny I already have the exact BAFX scanner that he said will not work. I use it in my truck pulling my camper to watch oil and trans temps with TorquePro


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## TyGeR (Oct 24, 2016)

I wanted to post an update. I ordered the MX+ OBD tool that Snipesy posted in the Youtube video. After swapping the DEF tank heater again and the NOX1 sensor, I ran the DEF Fluid Quality Test per the guide FOUND HERE. My car passed the test, after the test finished and my car showed passed the DEF Fluid quility poor fault cleared. My car is out of limp mode and back on the road. I understand why all the emission junk are on newer vehicles but I still wish I could rip it all out and tune it out of my car so I never deal with it again!


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