Hi guys! First time trying to diagnose a car here. I have a 2013 prius C which just been to maintenance at 80k miles. A few weeks later I got a check engine light on. I was informed that I could use a OBD2 to check what the warnings are, so I bought one and see p0441 and p0455 codes. Looking up the codes and see it’s usually about the tank cap which I already tried tighten before using obd2 but it didn’t turn off the light. One of the guide I found just tighten the cap and clear the codes. So I did the same. I looked at the cap and don’t see any cracks. My question is that when I clear a codes, would it reappear if the problem persist? In my case if the problem wasn’t the tank cap, would the check engine light show up again? I’m just wondering if I actually fixed it or I’m just ignoring a problem that could cause future damage
These errors relate to the evaporative emissions control system. Basically all the stuff that prevents your gasoline supply from evaporating away on a warm day. The bad news: this is a very complex system and there's a long list of potential causes for those two codes. The good news: even when it is all broken, it doesn't affect the way the car drives. It might prevent you from passing an annual inspection if that is a thing where you live. It can be as simple as a bad o-ring on the gas cap, or a rotted or mouse-eaten vacuum hose up under the hood somewhere. Sometimes they don't figure it out until somebody hooks the car up to a smoke machine- you blow theatrical smoke into the vacuum system and pay attention to where it comes out. Usually when you reset an evaporative code without actually repairing the car it takes a while to come back, but certain failure types can be detected immediately and would re-fail immediately. Because the list of possibilities is so long, it really is worth renting the factory service manual and stepping through it. Or pay a shop to do it. Good luck!
Thank you for your the answer! The links will come in handy as I plan to start doing more DIY repairs.
I've recently fixed the same problem on a 2015 Prius С. It looks like some kind of animal has chewed on the pipe.
