# Codes tonight



## Eddy Cruze (Jan 10, 2014)

Depending on your State we have heard some great stories. Why not go to My Chevrolet . Com where you can register for everything related to your CRUZE, including any current warranty coverage. I hate that site and they even use a different CRUZE forum. Plus you want to check your State Warranty Chevy booklet & your State laws


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## revjpeterson (Oct 2, 2013)

If it's a 2014, the NOX sensors somehow got exempted from the 8/80, so they were only covered under B2B. warranty. NOX1 is covered for 1 replacement at the time of the ECM programming recall, if you're subject to that, but not NOX2. If it's a 2015, they updated the warranty to include the NOX sensors in the 8/80. With the pairing of codes you have, it's possible it's a faulty NOX sensor, but also could be a failed/clogged DEF injector, or even a wiring issue.


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## MackNCheese (Jan 19, 2020)

Nothing is clogged. I have Biscan also. Soot is only at 16 grams. It's been 615 miles since last regen, so that's not terrible! I think it's getting close. I just got it so I believe maybe someone had a bad tank of gas since I used only shell in all of my vehicles.


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## revjpeterson (Oct 2, 2013)

MackNCheese said:


> Nothing is clogged. I have Biscan also. Soot is only at 16 grams. It's been 615 miles since last regen, so that's not terrible! I think it's getting close. I just got it so I believe maybe someone had a bad tank of gas since I used only shell in all of my vehicles.


The potential clog wouldn't be in the DPF (the part between the engine and radiator that collects soot and is cleaned during re-gens). It would be in the injector for the Diesel Exhaust fluid--the nozzle inside the exhaust, under the car and behind the engine, which is part of the SCR system to reduce Nitrogen Oxide emissions. Sometimes the car will think a NOX2 sensor has failed, but really there's just not enough fluid being injected into the system. The "catalyst efficency below threshold" code especially sets off a warning of a problem in the fluid delivery or injection, because a failed NOX2 usually doesn't set that code with the NOX2 circuit low code.


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## MackNCheese (Jan 19, 2020)

revjpeterson said:


> The potential clog wouldn't be in the DPF (the part between the engine and radiator that collects soot and is cleaned during re-gens). It would be in the injector for the Diesel Exhaust fluid--the nozzle inside the exhaust, under the car and behind the engine, which is part of the SCR system to reduce Nitrogen Oxide emissions. Sometimes the car will think a NOX2 sensor has failed, but really there's just not enough fluid being injected into the system. The "catalyst efficency below threshold" code especially sets off a warning of a problem in the fluid delivery or injection, because a failed NOX2 usually doesn't set that code with the NOX2 circuit low code.


Well my DEF fluid has gone down from ok to 30 percent.


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## revjpeterson (Oct 2, 2013)

The NOX 2 sounds like it might be the leading candidate, then. If that's not it, then you could be still using DEF, but it could be flowing at a reduced rate, have a poor spray pattern, or be escaping somewhere on the way to the injector.


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## MackNCheese (Jan 19, 2020)

Well I did a regen tonight and no codes. Maybe it was just dirty?


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## Snipesy (Dec 7, 2015)

MackNCheese said:


> Well I did a regen tonight and no codes. Maybe it was just dirty?


Possible. Regens clean the entire exhaust system, including the DEF injector.

Although not in BiScan, Gretio has various test procedures which tend to set off emissions code much quicker than just driving it. They do things like DEF quality tests, Heater tests, NOx sensor tests, and some other random things.

Sadly between those tests and the Regen we don’t really get anything to diagnose emissions problems


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## MackNCheese (Jan 19, 2020)

Snipesy said:


> Possible. Regens clean the entire exhaust system, including the DEF injector.
> 
> Although not in BiScan, Gretio has various test procedures which tend to set off emissions code much quicker than just driving it. They do things like DEF quality tests, Heater tests, NOx sensor tests, and some other random things.
> 
> Sadly between those tests and the Regen we don’t really get anything to diagnose emissions problems


I just did a normal regen and was very pleased with how quickly it went through its cycle. I was only at 18 grams, but did it because of the NOx sensor. The car did feel to stumble some at one point, but was short lived.


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