2004 Chevy Trailblazer error code P0141

That would be the sensor behind the converter. It is possible it is the sensor, however it could also be a broken wire or bad connection to it.
I would check the wiring first, make sure it isn't chaffed or hitting the pipe so it got damaged. Unplug the sensor and look at the connector. Make sure it's clean. Clear the code and see what it does. If the code comes back, replace the sensor.
Don't use a cheap sensor though, they have a nasty habit of causing other codes.