Ok...I've read a few post about this but I'm just making sure I understand this. My CEL is has been on for awhile It says my down stream o2 sensor is bad. The car is seems to be running just fine. I have Corsa cat back exhaust and KN CAI. From what I understand those 2 parts might be causing the CEL to come on???? I have the 02 sensor I'm ready to replace it, but will this fix the problem? And if changing it out doesnt fix the problem what would? Thanks

 

It sounds like its just a bad sensor. The K&N wouldn't affect the downstream O2 sensor, and the cat-back is after it, so I think its the sensor itself.

 

The downstream sensor won't have any bearing on how the car runs, its just there to make sure the cat is doing its job, which in your case it isn't or the sensor is actually bad.

There are different codes to indicate if the cat or the sensor is bad. Any of the P0130-P0160 codes usually indicate a problem with the sensor, while a P0420 or P0430 indicate a problem with detected catalytic efficiency.

 

I wouldnt mind that being the problem...the next question is I didnt put the car on a hoist or anything i was just laying on my back looking but I couldnt see where it was at. I have never changed an o2 sensor b4 but I heard it was pretty simple. But I didnt see it.

 

Its on the driver's side of the car across from the front door (if its a 4 door). Its located in between the cat and the forward resonator (the long canister in the middle of the car). The only other o2 sensor on the car is located either on the manifold or directly below the manifold depending on model and year, and of course its located before the cat.

 

well i just checked my paper work and the code it threw was the po420 so does that mean I need to replace the catalytic con. cuz that would suck its well over 300 bucks lol

 

P0420 is usually a cat problem. There are a number of things that can set that code off such as high sulphur gas or an exhaust leak. They are under a warranty for up to 80,000 miles I believe so there shouldn't be any trouble with having the dealer run a diagnostic and replacing it with no out of pocket costs.

 

ok that sounds good to me but what about the after market mods. I also have a fuel controller on there....not set up but it is on there. I've been having problems with dealers where I am....and Thanks for your help

 

Anything that alters air metering or fuel delivery may be a problem when you take it in, whether its installed or not. Most dealers will try everything to not cover the repair and have you pay for it out of pocket and if they get a hint that something you added to the car could have caused the cat failure most will immediatly blame that.

All this just from prior experiences, all dealerships are different however.

 

ya....I'm hoping to take it off since I dont use it. And hopefully there wont be any problems then....I apprciate your help I'm not the brightest when it comes to cars lol

 

Are you in limp mode?

 

whats limp mode?

 

Ask Witt lol

It was more of a joke...don't think you're in limp mode.

 

lol @ u

 

When your DIC reads "reduced power" you'll know what limp mode is!

If you ever see it you'll be lucky to get home -- find a safe place ASAP to park instead!!!