what does code 0422 mean? and 0455 mean? what needs to be repaired

 

Well P0455 is a large evap leak, P0422 there no such code, unless you mean P0442 which is a small evap leak.

 

P0422 indicates that your computer thinks that the catalytic converter is not working efficiently. This can be because it isn't, or because your computer thinks it isn't. The downstream O2 sensor (after the cat, if equipped) is where the compter gets it's info from. It may be the culprit.