2006 corolla. In the pics I am poking a rusted hole on this part (which I dont know the name of). What is this part called? It appears to connect to the exhaust system. How would a hole like this affect the car? Could it trigger a P0420 error code? (I am currently experiencing that)
In the mean time I covered it with metal tape.
4 images of the part / damage: Imgur: The magic of the Internet
I can see exhaust hardware with the springs.
Rusty heat shield?
Tester
+1
If it is a heat shield, that would not cause a P0420 code to pop up.
The remedy for that code could be as easy as the replacement of an O2 sensor, or–worst case scenario–it could necessitate replacement of the catalytic converter.
Seems like multiple layers rusted, does exhaust leak out of it? If not, then it’s just the heat shield rusted.
Ask your shop to use their pro-level scan tool to inspect the pre- and post-cat o2 sensor signals. When they see the the voltage vs time traces side by side, they should be able tell you if your Corolla’s cat is good or bad.
The exhaust system on modern car’s must be air-tight for the engine to work correctly. If you have an exhaust system leak, that could confused the powertrain computer to make it think there’s a cat problem when in fact there isn’t. So it is a good idea to also ask your shop to check for exhaust system leaks.
very important question 
