How do I check for leaks or cracks in the ehxuast system?
 

How can i do this myself?

MY 02 sensor throwing codes, some people say check for exhaust hairline leaks, or malfunctioning cat.... something i can do at home?

what code specifically is it throwing?

hairline leaks you can hear and see if you plug the muffler outlet.

You can do it yourself if you have a gas meter??

throwing p0156 AND p0133

Bank 1 sensor 1 and Bank 2 sensor 2 malfunction

Might be the O2 sensor itself, replaced one on a Civic throwing the same codes and they went away.

p0133 is slow sensor
p0156 is malfunction sensor

while it's easy to just replace the sensor for the 2nd one since it's not working as well as the first one since it's not reading as fast anymore, you should see why it failed if it's relatively low mileage.

2nd sensor could be failed because of a broken cat, and the 1st one could've failed because of an exhaust leak causing it to think lean and make the engine run leaner, throwing more fuel and burning out the cat.

or it could just be old age.