P0135 and P0155
 

Ive tried to search and figure this out with no luck. Im throwing both of these codes.I know they are Heated O2 sensors but I dont know what ones or if I have more then 1 set. The parts guy told me they would be up on the manifolds but read a post where it says its near the converter.

Im gonna go fix the broken weld on my cat and hopefully some one will have a answer when I come back. its a 01 6.0 silverado.

alrighty.. leak is fixed.. any one? for whats its worth I think next time ill take it to the shop to have it fixed.