1997 Chevy Tahoe O2 Sensor or Cat Converter?

Hi
We recently purchased a 1997 Tahoe with 126,000 miles (5.7 L V8). At the time of inspection the Check Engine light was on. We had our mechanic check the codes and it indicated "Converter Efficiency and O2
Sensor Heater Failure on Bank 2". They recommed replacing the cat converter.
The gentleman we bought the car from was a mechanic and he was CONVINCED that the cat converter was not bad. He thinks it is a bad O2 sensor.
Any thoughts?
Oh yeah... and our horn keeps beeping?!? Previous owners had removed the fuse. We put it back in and the horn goes off once you start driving.
Thanks~
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Change both.After that take you negative terminal off the battery for 10 minutes or so.Computer will reset and codes will clear.The truck may or may not run a little ruff for a few miles,dont worry, its just the computer reseting all the perameters, it'll smooth out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.