# Poor def fluid light



## snowwy66 (Nov 5, 2017)

You'll have to go do the dealer for a computer diagnosis. Some sensor or possibly def or dpf is bad. 

Semis do the same thing.


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## Rivergoer (Mar 30, 2017)

Related thread, hope this helps:

https://www.cruzetalk.com/forum/201...1-exhaust-fluid-quality-poor-caution-dic.html


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## revjpeterson (Oct 2, 2013)

If DEF Poor message is due to a sensor, overwhelming odds are that it's NOX2 (NOX1 was replaced in your recall service). Actual problems with the fluid itself are rare, unless it's being contaminated, but the injector does sometimes become clogged, preventing the fluid from doing its job in the SCR unit.


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## MP81 (Jul 20, 2015)

Have you had any CELs to go along with this, as well?


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## Tdipwr (Dec 16, 2018)

Ok took car to the dealer last week and after 3 hours of diagnosis they said maybe the control module was bad. They reset the light and all was well for 4 days and Sunday the light is back on and we already down to 65 mph limited speed. This time check engine light is on with a code 249d. I feel like the dealer doesn’t know what’s wrong and is guessing at the problem. I hate to just throw money at it.


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## Rivergoer (Mar 30, 2017)

Tdipwr said:


> Ok took car to the dealer last week and after 3 hours of diagnosis they said maybe the control module was bad. They reset the light and all was well for 4 days and Sunday the light is back on and we already down to 65 mph limited speed. This time check engine light is on with a code 249d. I feel like the dealer doesn’t know what’s wrong and is guessing at the problem. I hate to just throw money at it.


The challenge is the source of your P249D and ‘poor DEF quality’ could be several possibilities, difficult to isolate which one. 

More related info HERE

If the dealer is throwing parts at it, maybe time to try a different one...good luck and post an update when you know more.


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## Ma v e n (Oct 8, 2018)

P249D denotes that insufficient DEF flow into the SCR has been detected. This can be due to poor DEF quality, a poisoned SCR catalyst unable to process DEF properly, something not unbelievable at nearly a quarter million miles. It could a NOX2 sensor failure to accurately read. Additionally a common cause is an electrically good, but mechanically failed DEF injector.

All of these require proper access to data to determine functions of components, and ideally functional controls.


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## Tdipwr (Dec 16, 2018)

Dealer did mention that the DEF doesn’t have a real long shelf life and they have seen it go bad. We been using the rural king brand DEF and haven’t had any issues before. I believe I’m going to take a stab in the dark and completely drain the DEF tank and refill it with the Blue DEF tomorrow and see what happens.


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## Rivergoer (Mar 30, 2017)

General Question...does the P249D code and countdown mean the car needs to be reset by GM dealer after drain/fill of DEF tank?


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## 14diesel (Feb 18, 2018)

I'd ask them to check NOx sensor 2. They can pull up the data stream for sensor 1 and 2. Accelerate to 45mph and coast. Both sensors should drop to near zero almost immediately. If sensor 2 is hanging, I would be suspicious. That's what gave us the poor DEF quality light and P20EE. I think the sensors need to drop below 5ppm after a certain amount of time. Our sensor 2 was hanging at 9ppm.


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## Dieselfever (Feb 23, 2017)

Problems with the SCR are frustrating and dealer service departments unfortunately are little help. What is impressive and encouraging is that the OP has 245k miles on a non-deleted CTD and is still ticking. We bought our Cruze to be driven like a rented mule. It is our hope to achieve at least 300k, hopefully without any major repairs.

No one has mentioned it yet, but OP could send his ECM to OZ tuner and have the SCR turned off. He will never experience a DEF related problem ever again. Now, this suggestion will trigger those that fear that turning off the SCR will kill old ladies and little babies. My only comment is to say that we already know how you all feel and there is really no need to regurgitate your opinions again. ITT!

I sincerely hope OP is able to find a solution and wish many more happy miles on that resilient Cruze.


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## Ma v e n (Oct 8, 2018)

Rivergoer said:


> General Question...does the P249D code and countdown mean the car needs to be reset by GM dealer after drain/fill of DEF tank?


General answer, yes most tamper DTCs need to be reset with a service test initiated by a scan tool in order to clear a countdown.

And yes it can be very frustrating to find a competent GM diesel technician...diesel and advanced technology vehicles(bolt,volt,hybrid) are the two GM mechanical certification focuses with the fewest certified technicians. Simply because so many dealers don't care if they can sell diesels or EV, so they don't bother to be sure that they have a certified tech on staff.

I've been asking and pushing for years for GM make available a resource that would allow consumers to locate a dealer with World Class and other speciality Master Certifications. They refuse to.


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## Tdipwr (Dec 16, 2018)

Well if up to me we would just delete the car and life would be great but my wife drives it everyday and doesn’t like the old diesel smell. I pulled the tank today completely emptied it and refilled with blue DEF I don’t expect a change but time will tell. We only have about 25 miles left until Speed limited to 55 begins.


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## Tdipwr (Dec 16, 2018)

Well I’ve emptied the DEF tank and refilled with new and removed the DEF injector and cleaned it and removed the nox 2 and wire brushed it off. Still nothing has helped I’m down to 55 now soon to be at 4 mph. I’m thinking of deleting the system any thoughts on how much this cost or where to get the parts?


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## 14diesel (Feb 18, 2018)

Brushing sensor 2 won't do anything. It should be pretty clean anyway as it is post DPF. You need a computer and dealer tool to see what the sensor is doing real time. From what I remember if you want to delete it's around $900-1000 for tune and parts.


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## Rivergoer (Mar 30, 2017)

Unfortunately to reset the countdown you’ll have to see the dealer. 

Delete and tune info here

https://www.cruzetalk.com/forum/169...npipe-egr-delete-oz-tuning-flash-install.html

About $1,260 on eBay (OZ Tuners)


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## Tdipwr (Dec 16, 2018)

Well took the car back in to the dealer yesterday and they had it for over 2 hours. They said nox 1 sensor was bad which we just had replaced under recall or so we thought. Turns out last time we took it in for the recall they just re-calibrated it. Anyhow after much frustration they replaced the nox 1 and all was well until today. Well over 4 hours from home it decides to come back on and now its at a dealer 2 hours away and we ended up with a rental to get home. I’m really at the end of my rope with this thing we love the car but dang is it ever gonna get fixed.


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## Dieselfever (Feb 23, 2017)

Tdipwr said:


> Well took the car back in to the dealer yesterday and they had it for over 2 hours. They said nox 1 sensor was bad which we just had replaced under recall or so we thought. Turns out last time we took it in for the recall they just re-calibrated it. Anyhow after much frustration they replaced the nox 1 and all was well until today. Well over 4 hours from home it decides to come back on and now its at a dealer 2 hours away and we ended up with a rental to get home. I’m really at the end of my rope with this thing we love the car but dang is it ever gonna get fixed.


Take the red pill and delete. It is diesel utopia. If not a full delete, a partial delete by having the def turned off can be accomplished. You will be happy.


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## Roger Ramjet (Oct 11, 2018)

I would call GM Customer Service and report that the dealership is unable to properly diagnose the issue and force the dealership to communicate with Tech to resolve issue.


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## Tdipwr (Dec 16, 2018)

Ok so car went to dealership agian last week and they replaced nox 2 sensor and had the car for 2 days. After day 2 they said we needed to replace the SCR filter at a cost of 1,700. I’m very sceptical if this is the problem. The dealer said they couldn’t get the countdown to reset so we decided to just pick the car up and bring it home. About halfway home the light went out but only lasted 3 days. The car only has 12 miles left until limited speed of 4 mph so it’s parked. I’m calling gm tomorrow just to see what they have to say but probably gonna bight the bullet and order the delete kit.


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## MP81 (Jul 20, 2015)

I can't say I've heard of a failed SCR yet.

They can only make the countdown go away if the system determines there are no other issues during the test/check procedure. We had the particulate sensor fail, leading to an emissions countdown. It was replaced (special coverage warranty on that), but the countdown wouldn't go away likely because the NOx 2 sensor was throwing a code (and had been for a year or two at this point - I don't think the NOx 2 itself will cause a countdown). I had to replace that, then have them re-run the check, and it went away.

But at $1700, the delete is cheaper, and you know you'll never have to deal with anything emissions-related ever again.


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## Lilygraham2023 (3 d ago)

revjpeterson said:


> If DEF Poor message is due to a sensor, overwhelming odds are that it's NOX2 (NOX1 was replaced in your recall service). Actual problems with the fluid itself are rare, unless it's being contaminated, but the injector does sometimes become clogged, preventing the fluid from doing its job in the SCR unit.


 What can u do if the injector is clogged I'm going through this right now and no check engine light just diesel exhaust fluid poor pls help


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