My s40 failed for 3 codes p0420,p0700,&p0705 I had a hole in the exhaust fixed & the 705 netutal safety code went away and the 420 code is pending will this code go away?

Codes like these need their tests run. Google them or seek the glossary and possible causes at enginecodes.com. codes that come and go have reasons why they set. they may return in some cases because healing is not something the vehicle can do.

since you fixed he hole in the exhaust, you may have fixed the problem. as long as you are not having drivability problems, turn the code off and see if it comes back. if so then you still have an issue.

And you can save a week, by following the code read, pinpoints, and resetting the power supplied to it, a relearn would take a day . lets see what actually happens....let us know how it actually goes

My s40 caterlist converter is blocked can I drive it without them