Hi,
The P1457 is specific to the EVAP system and sets when there is a leak. In this case, the code is related to a leak in the canister system.
The P0420 is related to the catalytic converter. In most cases, the converter is worn, no longer performing, and needs to be replaced.
I'm not sure where you are located, but if you are in an area where salt is used during the winter to clear roads, there is actually a technical service bulletin related to this code that points out that in areas where salt is used, there is a higher chance of the problem. I attached the TSB below for your review. In addition, the TSB also includes the diagnostics related to the code.
Take a look through the TSB and let me know if you are comfortable performing the tests.
Take care,
joe
see pics below.
Images (Click to make bigger)
SPONSORED LINKS
Saturday, October 28th, 2023 AT 10:15 PM