Fabio-Z06

I have codes that went on my car (P0030 and P0135) which is for the oxygen sensor on the drivers side before the cats. I just can't seem to find it though?

Can someone please direct me to exactly where the o2 sensor is on the drivers side? Anyone have a schematic or an actual picture or video of where it is and how difficult it is to get to and replace?

LeftLane Z06

pic of the cats.... located right off the exhaust manifold.

LeftLane Z06

Probably have to drop exhaust manifold to change the pre cat 02 sensor.

Fabio-Z06

God forbid it was the o2 sensor after the cats that could be changed out in two minutes....

Thank for the help guys.

By any chance anyone have a video of this being done?

Fabio-Z06

Forgot to mention that I do have dynatech headers and full corsa exhaust. Would the o2 sensors still be in the same area?

LeftLane Z06

should be easier to get too. Still might have to remove all the header bolts to allow for movement to get 02 sensor out. Not a hard job...maybe a hour or two.

LeftLane Z06

But I think you can get it out with no problems. You should be able to see and get to it once you get under the car.

Fabio-Z06

Really appreciate the info.

redbird555

Just for anyone who read this thread you can change out the top O2 sensor without dropping the manifold on a stock car. Usually under the car is easier

Fabio-Z06

Hopefully that is the case and maybe a bit easier as mentioned above with the dynatech headers. I guess once I have a minute to get under the car I'll figure it out.

Fabio-Z06

Their are only 2 oxygen sensors per side right?

I just went under the car and literally removed the first (bank one) o2 sensor in about 3 minutes. By reading a few of the post above it seems as though this should have taken me at minimum, an hour. Did I remove the wrong one? The other sensor closer to the back of the car seems like it would be more difficult to remove.

Here is a pic if both spots.

Fabio-Z06

One more

Dan_the_C5_Man

The one you removed is a pre-cat O2 sensor, the other pic with the two next to each other, those are post-cat sensors.

The location and relative difficulty of removal is going to vary based on the brand of header. For example, it would take me a lot more than five minutes to replace the front O2 sensors on my Kooks.

Pre-cat sensors provide the ECM with a feedback loop for fuel mixture adjustments. The post-cat sensors are just there to check the cat efficiency and operation.

Fabio-Z06

Yes. I removed the "upstream" as I've just learned it to be called while
trying to order it from auto zone.

Hardest part was getting a jack under the car. While down there should I replace others? Probably not worth it I'm guessing right? I guess just change if another one goes at some point.

Dan_the_C5_Man

Well, unless they were poisoned by coolant or other foreign material, O2 sensors are very durable and last for tens of thousands of miles..

How many miles on these? If very high mileage, then yes, replace the other pre-cat O2 sensor.

Remember, the pre-cat sensors are critical to engine fueling. The post-cat sensors are more like a yes / no feedback loop to make sure you haven't removed the cats or to validate they are working properly. Most tuners eliminate the post-cat O2s from the ECM configuration.

Fabio-Z06

My car only has 9000 miles. I guess I'll leave the others alone. One of the wires seemed to have been a bit melted from being to close to the exhaust.

Fabio-Z06

I received my o2 sensor and replaced it. Do I need to have a code reader eliminate the check engine light or do I just drive it a few times and it should shut off?

Not sure when I'll want to drive it if I need to go that route since they salted the roads. I don't want to take it out on salted roads.

Dan_the_C5_Man

You can either reset it with a reader or drive it a few cycles until it clears on its own. Also, check the related fuse.

Fabio-Z06

Thank you.

Would you happen to know how to check which fuse is related to the specific o2 sensor?

Dan_the_C5_Man

IIRC there are two, either tied to fronts and rears, or left and right pairs (if I was home I'd go down and look). Either way, just look at the labels on the inside of the fuse box lid in the engine compartment - you'll see it.