Hey guys, This is actually a freind of XCRuna1201, he's at work right now. We just put on a zzp header and downpipe combo last night, but on his way to work in the morining it threw a CEL. I got my scanner out and its saying P0102 and P0420. Anyone have these issues, I think it might be the first O2 sensor after the header, it seemed to not screw in far enough, but I'm no cobalt expert. Help please?

Thanks,

skipthedrummer

 

well, p0102 is MAF low frequency code....not sure how the header would affect that

p0420 is catalytic efficiency code.....I hear lots of people get that w/ the zzp combo....Make sure the rear o2 sensor is in all the way. If it's loose and air is getting in it will alter the o2 readings and set that code as well

 

p0420 is low cat efficiency, and p0102 is for the mass airflow.

 

thats what i thought, it said catalytic threshold not met, so I figured air's leaking somewhere, i guess if its the cat its gotta be the second o2.

-edit: lol I know what the codes mean, I'm asking really if anyone has had the problems and how they fixed them. Sorry if it seemed like I needed the code description.

 

well, sometimes the high flow catalytic converters won't meen the factory emissions standards.......and that code will set. Probably just end up disabling it through HP Tuners or something

 

Has anyne tried the spark plug fouler mod with this car? What it does is trick the computer from seeing that the car no longer has a cat.

Here's what you do...

1. Disconnect battery (positive or negative side, doesnt really matter)

2. Purchase 18mm spark plug foulers (comes 2 in a pack, and can find them at any local auto parts store)

3. Drill it out with a 7/16th drill bit. (Needs to open up so the sensors probe will fit inside.) DO NOT DRILL ALL THE WAY THROUGH!

4. Once drilled, screw it into the o2 sensor bung then screw the o2 sensor into the fouler.

5. Connect battery back up.


NOTE: Sizes may be different for the cobalt. Hell, this mod may not even work, but for 3-4 bucks it wouldnt hurt to try. If it did it would be beneficial to those who dont have HPTuners to clear the code.

 

so is the computer not gonna try to lean it out or anything? As I understand, stage 2 is a little rich, and nated 2.9 lowers it down a little. He's not gonna lean it out if the computer trying to cut back on fuel or anything?

 

well, changing the pully isn't going to really lean it out the right way......the computer will still command the same AFR, but now the injectors will work harder to get there.

 

is there a site you can go to 2 get all the codes an what they are? couse im also throwing a few myself

 

the p0420 code is just from the high flow cat. im assuming you have it. its just a difference in reading between the two 02 sensors. i got that same code after i put my zzp head/dp on too. not sure about the other one.


and search "DTC Codes" there is a whole list of them on here.

https://www.cobaltss.net/forums/problems-service-maintenance-69/cobalt-dtc-thread-merged-12015/

 

There is a program you can use. All hail ALLDATA

 

the other one is about a mass air flow sensor i believe?



How did you get the codes to go away?

 

i have an aeroforce interceptor scan gauge so i can delete the code, but it will come back 5 mins later....i just drive with it on, but i regularly check to make sure i dont have any other codes.

With HP tuners you can delete the code compeltly so it never comes back.

 

hmm now I gotta find soimebody with an HP tuner....damn...anyone in Georgia?

 

So is the P0420 code the 1st or 2nd o2 sensor, I have had this code for almost a year and my car is running like ****, I am going to tighten both of them nice and good but I'd like to know which one it is PLEASE. for future reference i suppose

 

the p0420 is a catalyic efficency code, not really for either o2 sensor

 

http://www.obd-codes.com/p0420

http://www.obd-codes.com/p0102

 

Im replacing all gaskets and bolts etc with the original GM ones, and I'll need both o2 sensors as well. Anyone know the part numbers or something I can go by. Only way to fix this is to replace everything with known brand new working parts and secure them properly and see what happens.

 

it has nothing to do with the o2 sensors really, its the computer thinks its supposed to be reading a certain number but since you have the high flow cat (or not cat) the readings are off, and to be safe, whenever somthing is off the car will throw the CEL just as a precaution...BTW o2 sensors are expensive as **** man, like 250CDN.

and my car runs fine, maybe you have another problem...

 

try the spark plug fouler approach first.

Then move on from there

 

Im not sure exactly what that is but my plugs were white a few months ago when i pulled them out and replaced them, i went back to an earlier tune and the plugs have been fine since.