# P11CB Code Set



## pacolino (Aug 1, 2015)

oreo382 said:


> Just had this code set the other day.I searched the posts and did not find any similar references.
> From what I can determine it is a NOX 1 sensor problem? I just had this sensor replaced a few months ago
> but am sure the code at that time was different.40,000 km on the car.Any thoughts on this?


Are u sure is Nox 1 sensor? It's first time I see it.

Sent from my SM-G930W8 using Tapatalk


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## boraz (Aug 29, 2013)

https://service.gm.com/gmspo/mode6/pdf/2014/14OBDG04 Engine Diagnostics.pdf

p119

nox 1 sensor


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## MRO1791 (Sep 2, 2016)

From the GM Diagnostic ECM Summary: 

P11CB: 
Component / System: NOx Sensor Performance - Signal High Bank 1 Sensor 1
Monitor Strategy Description: Detects a high deviation of the measured NOx sensor concentration from the modeled NOx concentration.

The 3 images are all for P11DC, splice them if needed to read the details.


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## snowwy66 (Nov 5, 2017)

An obd2 app should give you the defenition.


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## MRO1791 (Sep 2, 2016)

Also, 
The "enable" conditions needed to get code P11CB


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## MRO1791 (Sep 2, 2016)

If you had this sensor replaced, then got the code.. one thought I'd have is did the dealership reset the fuel trims with the replacement? That should be standard practice. The ECM has to learn the characteristics of the new sensor and it compares it to calculated values.. this data is built up over time of running the engine.. replace a sensor with no reset, and a perfectly good sensor could look bad to the ECM expected values based on data it has stored from the old sensor.. If I had to guess.. I would say there is a chance that is it, or perhaps it's just a bad sensor from the factory.. that does happen at times. Good luck.


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## oreo382 (Sep 17, 2014)

Yes the dealership reset the trims according to the paperwork.They replaced the sensor about 4 months ago.
I'm taking it in tomorrow so i'll let the forum know what was done. Thank you everyone for your replies to this.
This cruze is becoming an emission nightmare,lucky I have extended warranty,however either a delete or trade in is coming up.As far as emissions is concerned "lemon" comes to mind. Too bad because the engine (power and torque) is one of the best I have owned.
One other thing I just remembered,prior to this code I noticed the trans shifting very late a few times?


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## oreo382 (Sep 17, 2014)

Another update.Went out today and after a few shutdown and restarts the check engine light went out?
Still going in tomorrow as there should be a code in the memory.


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## MRO1791 (Sep 2, 2016)

oreo382 said:


> Another update.Went out today and after a few shutdown and restarts the check engine light went out?
> Still going in tomorrow as there should be a code in the memory.


Yes, it will still have the error code in memory, and freeze frame data of the problem. Given the descriptions I found it could be a transient condition that may not come back. What is your drive profile? The emissions system does not work well in short drive/city type driving, and fares even worse in that pattern in a cold climate, which I'm sure you have.


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## oreo382 (Sep 17, 2014)

Yes my driving is mostly city. Interesting you mention that because yesterday I went on the highway for about 1/2 hour and today the code went out. Maybe it needs an Italian tuneup once in a while.


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## oreo382 (Sep 17, 2014)

Update, I decided not to take the car in unless the code came back and so far it hasn't.
My best guess is the sensor was soot covered from cold and short tripping and the highway trip cleaned it off.
Will keep an eye on things and if it happens again will try the highway before taking it in.Knowing this may save someone not under warranty some cash.


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## MRO1791 (Sep 2, 2016)

oreo382 said:


> Yes my driving is mostly city. Interesting you mention that because yesterday I went on the highway for about 1/2 hour and today the code went out. Maybe it needs an Italian tuneup once in a while.


Spot on, if you are able to do at least a longer drive once or twice a week, it could save many issues. I monitor for Regen using Snipesy's Bi-Scan for GM with the Torque App. Others use the ScanGuage 2. If you can know when the car is in, or near regen.. you can let it finish by doing a bit longer drive, and it will prevent many issues. 

The Bi-Scan app lets me force a normal regen early, if it is close, so I can have it complete before I arrive at my destination. It also lets me command a service regen, if that becomes needed.. Something the dealership will charge about $200 to do.


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