2005 Chevy Silverado with a 6.0. Has near 200,000 miles and is due for emissions test. Boss doesn't want to sink any money into it because it's due to be replaced within 6 months, but emissions test is due now.

It has a recurring P0420 and P0455 code coming up.

I was asked to disable these two codes to "no error reported", but didn't know whether there is any negative or ill effects that may come about from doing this? Will it pass the "readiness" tests?

Thanks.