Zach06CobaltSC

My interceptor gauge says I have a code, and I have the CEL. The code is obviously P0420. I am assuming it is because I do not have a catalytic converter. Is this correct, or is there/could there be another problem?

madmark

iTrader: (1)

gato =\

thatotherguy

Nope p0420 is low cat efficiency.

madmark

iTrader: (1)

which means leak or bad cat

Zach06CobaltSC

I have no CAT. I took out my cat. So isn't this code because I do not have a cat?

Zach06CobaltSC

it can't be clogged...i don't have one.... my cat is sitting in my trunk guys. Maybe i miss typed this.

I do not have a CAT on my car. Am I having the P0420 code because of me not having a cat, or is it for something else?

thatotherguy

Yes its just a big change flow in air so its hitting that o2 sensor and its not use to that.. theres an aftermarket 02 sensor i think you can get and there wont be a code for not having a cat

Doc

what happened to the sensor..??
These are the errors/codes you can get without changing/disabling the codes with HPTuners

• P0036
• P0054
• P0136-P0141
• P0420

Zach06CobaltSC

Great, so I am having this CEL/Code because the car not having the cat. I can clear the code with the interceptor however it will come back. Not to big of a deal. I am going to purchase HPTUNERS so I will be able to permanently kill this code =D.

My next question is. I am soon having a 3inch header/downpipe/magnaflow cat being put on. Will I throw the same code, or will I throw a different code, or will i NOT have a code because the cat is there?

Doc - I am not sure if the sensor is still there or not. If you are talking about the o2 sensor, I believe they put it back where it belongs. Like, my exhaust is a custom made 3 inch exhaust, so I believe they made an o2 bung and welded it in or whatever.

thatotherguy

you can go get a tune and they can disable it foreverrr.


all you will have to do is unplug your battery for no more than 10 minutes and it should reset itself.

Zach06CobaltSC

Thatotherguy - correct, however it will come back in like 10 minutes if i reset the battery.

I plan on getting a custom tune in july once all my parts are installed, and hopefully will get close to the 300hp mark to the wheels, thats the goal.

I am also buying hptuners here shortly just so I can change little things myself, or with the help of the people online.

FASTL61

i was told the downstream o2 senser has nothing to do with fuel trim,all it does is monitor the cat (p0420)....so you can run with no cat,throw the code and still maintain proper AFR's

thatotherguy

It comes back somewhere around 80 miles or less. but if your getting hp then you wont have to worry about anything. any codes that show back up you can delet them

Doc

Its a simple fix to do when you have HPTuners.
It is annoying to turn the CEL off but you won't suffer if you don't turn it off.

thatotherguy

yeah what i meant was a 02 sensor that wont throw a code for having no cat... sorry if i made it sound weird lol

Zach06CobaltSC

Oh don't get me wrong, it doesn't bother me having the CEL on currently. I just wanted to make sure the code was because I didn't have a cat. I wanted to make sure it wasn't because my engine was gonna blow up lol. I don't know much about codes, and I couldn't really find anything with the search engine.

thatotherguy - yea, the o2 sensors are there and in place and all good to go, i just dont have a catalytic converter. I had the shop take it off when i was getting my 3inch exhaust done.

My next question though, is when i put my header/downpipe/cat on will i have this same code?

Currently I am having this code because I dont have a cat. So if i install the magnaflow cat, along with my headers and downpipe, I should not have a code. Correct?

thatotherguy

No the code will go away. the CEL only comes on if you dont have a cat and if you do put a cat on it then it will be like stock with no codes

Zach06CobaltSC

Sweet, that will be great. I ordered a 3inch header and downpipe along with a magnaflow cat from zzp. So then once thats installed, hopefully on wednesday/thursday i will not have the p0420 code.

thatotherguy

yepp correct

Zach06CobaltSC

Great. Maybe then I won't have to worry about that cel. Do you guys know if the Injen Cold Air Intake will make me throw a code?

Also. Did I choose the right setup for my headers/downpipe/cat. Is zzp good? I ordered the combo with 1 3/4inch high temp paint, magnaflow cat, mild steel downpipe, 3 inch downpipe, with 3inch bolt in exit. Add extra o2 bung for wideband. Send me a prepaid return label.

So did I make a good choice on the header/downpipe/cat combo?