2001 Blazer LT 2wd 4-door 4.3L Automatic.

Sunday night while driving back from Tampa, the T-pipe located under front end, blew apart/melted. Loud Exhaust noise is coming from this pipe.
The T-pipe has 3 rubber hoses connected to it. I believe one is going to the smog-pump behind the front bumper. The other two rubber hoses connect to a metal pipe and what I believe has a check valve on its way back to each exhaust manifold.

Found P0410 check engine code.
I replaced the plastic T-pipe that night, cleared code, tested vehicle to be okay. The next afternoon on mid-day start up the pipe broke again.

If I understand correctly, the smog pump it to pump fresh air into the exhaust system while the check valves are to prevent exhaust from taking this path to the smog pump. Correct?

So what could be causing this t-pipe to blow apart?
Could the smog-pump do this?
How do you check the proper function of the check valves?
These check valves are dealer only items at $50 each.

Thanks for the help.

 

If you have exhaust flowing out of the pipes, then one or more of your check valves are bad.