Oxygen Sensor located and can this be replaced from the ground?

[quote:171186078d="John Beesley"]Other Category problem
2003 Chevy Trailblazer 6 cyl Two Wheel Drive Automatic 125000 miles
----------------------------------------------------------------
Where is the 02 Oxygen Sensor located and can this be replaced from the ground vs. elevated

Thanks[/quote:171186078d]
Look on the left side(facing under the hood). There is a heat sheild with approx eight nuts, Try the bottom nut on the sheild first,(8mm or 10mm)If it breaks, stop and bend the sheild out, and try an open end 22mm wrench via wheel well access, insert the wrench behind the sheild. If you can not get it loose you will have to cut the orginal oxy sensor and even break the end of the sensor off to get a socket on it. Make sure you have the correct one on hand.
Install the new one and use the open end wrench behind the heat sheild to tighten.
Autozone has it cheaper then oem. bosch part #15285.

There is a before converter and after converter sensor, this is for the before sensor, never changed the after.

Hello,

This vehicle is equipped with 2 oxygen sensors.
One is on the exhaust manifold and the second one is after the catalytic converter on the exhaust pipe.

It will be best to replace them from under the vehicle. It will provide easier access. The one after the converter must be replaced from the bottom.

Here is a helpful guide:

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

I have attached diagrams showing both of the oxygen sensors as well as replacement instructions below.

Please let me know if you have any questions.
Thank you.