Hi Everyone,
My exhaust started to make some noise. Couple weeks after that i got a trouble code 0420. I didn't notice any power loss. Can it be just just a crack or a bad gasket in the exhaust system?
Thank You

 

Look under the car below the drivers seat on the exhaust, do you see a hole? Where a 02 sensor used to sit, but has now rusted off and is now dangling.

 

I just had this code and the dealer ended up replacing the cat on the y pipe. $700 for the job...

 

Does the RX sound different? any droning especially at fast idle?

The code means the computer isn't seeing enough difference between the precat O2 sensor and the post cat O2 sensor. The way to know for sure is to put it on a scanner and compare the O2 data to the FSM's spec and a visual and auditory inspection of the exhaust.. But the likely culprits are 1)the cat, 2)exhaust leak, 3)one or both O2 sensors.

 

Replace the rear O2 sensor....99 times out of 100 it has always solved my p0420's on any vehicle