Ok so here i am after almost a year of trying to get rid of this code and it just wont go away! I have searched all of the cobalt forums with no 4 sure cure for the issue. All of my issues started last march when i installed a ottp long tube header, 50lb injectors, 2.8 pulley, zzp 3" exhaust, dynatech cat, hpt tune by me after, 3" zzp intake, 9" long dry flow aem filter, 1 step colder plugs, devils own water meth, duel pass, option b, and s3 front mount. All of these mods were done all at once and not in steps. B4 this i had a gm stage 2, injen intake and gmpp cat back. From the first time i started the car after all of the mods it had bad idle surge and very bad open loop drivability. I have tryed the following to try anbd get rid of the issue. Clean tb, clean maf, replaced intake and blower gaskets, net gm o2 sensor, relocated o2 in header, checked for voltage drops and short to ground on o2 circuit, performed case learn, installed my 42lb injecors back in, re installed 50lb injectors, new injector o-rings, new injector harness, installed extra ground on header, tryed to tune it out, turned off p1133 hpt. After doing all of this i have no change with my o2 lack of switching issues. And for everyine that seys just delete the code and dont worry about it cuz it doesent hurt power is crazy! for instance when i tuned this car on the dyno it under part throttle in open loop my car would lose almost 35whp because my o2 was not responding fast enough. If i force the car to run in closed loop off of my tune only all of my power, and surge issues go away so thats making me think its all in the long tube ottp header. Has anyone ever had these issues after they installed a ottp or zzp header or anyother long tube? Or has anyone had this p1133 or p2a01 and actuly fond a way to fix it the correct way and not just delete the code

 

Sound like you may just have a bad 0-5v regulator in your ecu board. Replace ecu with another and retune. If problem persists maybe get a O2 extender bung..

 

what does the codes say exactly..?

 

When i datalog with my hp tuners the o2 volts swinging from .1 to almost 1 volt as it should but it does this very slow. Its causing my air fuels in closed loop to be all over the place and swing from 16.0 to 12.8 all the time. This is causing the car to surge all the time unless i am at wot. These codes are also causing my long fuel trims, short fuel trims, and timing to be all over the place. All if these pids are swinging up and down just like my air fuels are. I will also add that my air fuel cmd is staying @14.7 when all of this is going on so the computer wants a steady 14.7 but its not doing it. The p1133 code is HO2S insufficient switching bank 1 sensor 1. The p2A01 code is o2 sensor circuit range performance bank 1 sensor 1. All of the wires all the wat from sensor to pcm have been load tested and ohm checked and are ok. Brand new gm front o2 sensor as well

 

I solved my P1133 code by replacing my REAR O2 sensor. I know that it says bank1 sensor1 but I troubleshot that code on and off for over a year and finally heard from a few other guys (non cobalt) that reported having solved it by replacing the downstream sensor so I gave it a shot and it worked.

I even had the secondary O2 sensor codes turned off since I went catless so I figured it definitely wouldnt be that, but when i replaced it, the wire going to the sensor had frayed and the sensor part inside the exhaust was beat to **** when my honeycomb broke off inside my old hi-flow cat. Was fine for a while but i guess it eventually caused issues because my trims are back in line after being slightly off and I havent had a CEL in 2 months.

Weird that its a primary sensor code caused by a secondary sensor but it worked. Hope this helps.

 

Yeah that makes sence, seeings how is a/f is all over the place.. you could also look into the MAF sensor as well. Just a thought.

 

WOW, Good to know. Thanks. I just got that code on my 06 yesterday.

So do I. I have the ZZP High flow cat.

That is strange...
I'll keep the rear in mind when Looking into this. Thanks.