I started my truck this morning and saw my first check engine light in 93,000 miles since I have owned the truck. I almost thought it didn't work.

I recently dropped the fuel tank to change the fuel sending unit. I finished the repair Friday evening. All seemed well and the truck drove and ran fine. It still runs and drives fine. I have put on 60 miles or so.

I pulled the codes this morning and saw P0455 and P0441 (I think). My scanner also stated that there were some pending as well. Not sure if that meant that the CEL is only triggered after the code is set multiple times first.

I also did a google search for Toyota EVAP system and it appears to only check the EVAP after certain conditions. E.g., Time after driving, fuel level, etc.
Maybe that explains why I didn't see the light the following morning or evening after the repair. Meaning, in the morning the gas level was very low since I only had about 4 gallons in it. Later in the day I filled it up and started the truck with pretty much a full tank.

I opened my gas cap this am after the code and it appeared to feel odd. Didn't seem to have a lot or any pressure. Maybe I left the cap loose. I most likely doubt that since I have never done that in all the miles I drove.

I did have a problem with removing that big vent line that runs from the top of the tank to the canister. I also tried to remove that hose from the canister side but gave up and went to the tank side where eventually I got it off.


How should I proceed at this point?
Do I just bite the bullet and look to take it to a dealer to diagnose it? Not sure what the diagnose would cost.


To be honest, I wasn't even going to fix the fuel gauge issue but my better half was always concerned when driving the truck. It never really bother me since I would fill up and the look to fill up again after 300 miles of driving. I kicking myself for messing with it especially after what seems to be a successful head gasket repair.

I appreciate the feedback as always.

Before you take it to the dealer, check every one of those f*&#in quickconnect hoses on top of the tank. The bigger one I could have sworn was connected. Got the error, and sure enough it popped off in my hand with no tool or froce.

Each of those hoses has an o ring that goes around the point its connected to. They tend to not be in great shape, so I'd get a set of O-rings from your local hardware store and replace them. When they are old, they get loose, and then when you go to seat the hose they end up out off the track, which keeps it from sealing.

Try checking those hoses, and see where you are at.

Thanks. I truly believe I was very careful with any fitting with the exception of trying to remove the big fuel tank vent hose on both the fuel tank and canister itself. I was really squeezing and pulling on those things. In hindsight, I didn't realize how difficult it would be, at least for me, to remove the fuel tank vent hose. It looks like the most folks are using pick tools on this connection as opposed to simply squeezing with your fingers which is near impossible to do.

Is there an o-ring in the big vent hose or just on the fuel tank breather (blue connector)?

I am not considering the two main fuel lines as those carry fuel and not air or vapor. I assume my issue has to be with either the fuel tank breather line that I disconnected at the blue lock claw (in pic below), the big fuel tank vent hose, fuel tank filler hose, or the two plastic male pieces on either the gas tank or canister which the big vent hose connects to.

Quick update here. I just wanted to close out this thread. I ended up taking it in to the dealer for a diagnostic test on the evap system. I figured I would be out the diagnostic fee but would know definitely what was wrong. Just like I suspected, it was coming from the top of the tank were I struggled to get the main vent hose off. The tech suspected the o-ring rolled or was torn. I could have walked away and paid the diagnostic fee but ended up letting them go forward. After further investigation, the tech said that one of the o-rings was torn.

It does sting a bit to pay so much money for a single $70 vent hose especially after doing a fuel sending unit myself for $160 which included a new retaining ring, gasket and fixing a broken tank strap bolt. My logic at the dealer was once I heard what was wrong, I was already in it for the diagnostic fee plus the cost of a hose (~$250) if I took it home and did it myself. At that point, I just figured I would spend another $200 or so to have it done.

That's how this P0441 and P0445 story ends. A bit embarrassing especially after doing a head gasket job myself. To be honest, I really didn't want to go back under the truck.


@gimlithepirate - You were spot on about what was wrong. I guess woke up lazy yesterday....

i pulled my fuel pump assy to change the fuel pump and filter, cos of a persistent p0230 code. i got the assy out, but the fuel pump is encased in plastic housing, which i a peear unable to dismantle. any tips on how to get access to the pump?

I only changed the fuel sending unit and didn't touch the pump. Looking at the FSM, it appears to be straight forward.

Here's what the FSM says. Not sure if I am able to share this material.

https://i.imgur.com/iL2VfiB.png

Thanks.. yeah this is quite helpful. the 4 snap claws on the housing were quite tight and since i want sure of the correct procedure..didnt want to pry too hard. with this diagram, i can go all out and pry the shit out of that bugger