Diagnostics report help

[khrisx42]

Serivce Engine Soon light came on so i stopped at autozone for a code reading. This is what the report print out sais:

The PCM hasdetermined that the catalys system effeciency for bank 1 is below threshold for the current engine operating conditions. (Bank 1 identifies the location of the cylinder #1, while Bank 2 indetifies the cylinders on the opposite bank.)

Defentions
Catalys Effeciency low-bank 1
Explanation
The oxygen sensors monitor the catalytic converters
ability to store oxygen

Do i need to replace the o2 sensor? if so where can get some info on how to do this myself. I have a 2002 Tahoe LS.

Thanks for the help.

 

[JennaBear]

It is possible. However, it is likely that it is just the cat converter. Switch the rear o2 from the driver to the passenger and see if the problem moves to bank 2. If so, then obviously it is your o2.

 

[scott99zx6r]

Replace the cat and the o2 sensors.