[MINIAC12]

P015B seems 02 sensors, if you havent i would just replace them both, and P0171 is 02 sensor i think. I have a 2012 LTZ RS i fought the 171 code for a while. There is a purge sensor it has a hose connected to it. It is a hose that runs on top of the motor I replaced it and the code hasn't come back on. I'm not going to say this is your issue. I tend to do my own work. I trouble shoot by throwing parts at it and i still come up cheaper than the taking it to the Stealership. Thats the part number. Look into it. I might have had more going on it my car. Mine happened at the same mileage as yours 93,XXX. Hopefully this helps.
[h=1]PURGE CONTROL VALVE - GM (55577313)[/h]

 

[GreaCesar7]

i will replace the pcv hose when it comes in the mail but this will def be the next one i put! TY for the info!

 

[Gus_Mahn]

My daughter is 1000 miles away in college, so I had a mechanic change her valvecover on the side. It ran fine but started throwing the P0171 code on and off. Long story short, he lost the o-ring out of the PCV to turbo hose at the intake manifold.

The car was home for Christmas, so I changed the intake manifold (her check was missing) with a $20 pick and pull intake with a good check valve, replaced that hose, and did the front brakes which were fine at 72,000 miles other than pitting on the inboard rotor surface.

I have two Cruzes, so I trained my wife to change the purge valve and gas cap before her last trip to visit my daughter a few months ago. It didn't cure the P0171, but both can cause issues. Both were cheap enough to take the chance.