I tried searching for this code, and surprisingly only got 2 results. I also tried searching for the hose I need, but I don't actually know what the hose is, so my searches result in nothing.

I own a 2016 IS200t. I have been getting P0455 codes for months now. I have tightened the cap, and even bought a new cap from Lexus. When the tank is full the code seems to come more often. I started noticing a gas smell almost all the time, but even more so after filling up. I only allow the pump to click once and then stop fueling.

Today I removed the rear inner fender lining and went to the gas station and filled up. First click, I see nothing. I decide to do one more click, and then suddenly, I had gas pouring out from directly in front of the axle and onto the exhaust. I ran out for about 3 mins. I pushed the car out of the way and notified the clerk who came out and cleaned up the fuel. I sat there for 45 mins to allow it all to dry. Once home I jacked up the car and found the hose that goes above the driveshaft had been mangled by the driveshaft flange bolts. It was hard to get under there and I couldn't really see where the hose came from or where it went to.

Does anyone know what hose this is? Thanks for any help.

 

Any chance you too a pic of it?
I'm fairly sure we could find the hose and part number for you, and even where it starts and ends, but we're flying a little blind without a pic to start the process.
Here's a pic of the fuel system at the back of the car, and the link to where that pic came from: https://parts.longolexus.com/v-2016-...tem-components
Maybe this might help you.

 

So, it turns out that it's the hose that comes off the breather line (#11) in that pic. Unfortunately, it's not in that pic. It goes from the filler line to a green barbed connector on top of the tank.


It's highlighted in yellow. No part number that I see.

https://parts.hiltonheadlexus.com/a/...2430-7701.html

 

I hate to say this, but the line you highlighted comes with the gas tank by the looks of it.
You can confirm with the dealer, but I'm pretty sure it's made in a way the it's assembled onto the tank during production and cannot be physically removed.
That's why there is no part number in the diagram, it's part of the tank.
Note in the pic below the red arrows. The line in question is molded onto the green unit, same with the line that goes between the two pink units.

And the green and pink units are bonded onto the tank...they can't be removed either.

 

That is horrible news. I've only had the vehicle for 5 months now. Bought it as is.

I really need to think about what I am going to do here. I started getting the P0455 code about a week after I bought it. I found that the gas cap was not original. I thought this was odd, but who knows why the previous owner replaced it. I got a new one from Lexus and cleared the code. It stayed clear for about 2 weeks and then came back. I thought for sure it was just a loose hose, and I could only smell gas when I filled up.

What bothers me the most is that even though I bought the car as is, I feel like the code was cleared when I went to purchase the car. I think they replaced the cap, cleared the code and sold it to me. I say this because the code would continually come back between 1-2 weeks. And no one has been under the car. Especially in the area where that hose is. It's really hard to get to. This really sucks.

At this point, being the breather tube, I might consider repairing it. Not sure yet. If I can get the part, I will just replace it. I guess I will find out tomorrow.

Thanks for your help.

 

You can pretty much guarantee that the code was there prior to you purchasing the car.
The gas cap was likely their best guess as to what the issue was. Since it's actually leaking gas, the likelihood is the leak was there before, meaning the code was there before.
Although, like you said, you bought it "As-Is", so that kinda leaves you SOL for them fixing it.

Consider that hose shouldn't be anywhere near anything that can touch/impact it, first you should see how it possibly got damaged, and address that...then look at either fixing the hose or replacing the tank with a used one.