P0455 & P0441: Cleared Engine Light, but not Codes?

This morning i let my truck warm up for 5-10mins as it was in the low 20's and i was taking my 1 year old to daycare. When I got in my truck I noticed my check engine light was on... great.. Then I remembered two days and 30 miles ago I got gas. Most of Oregon an attendant pumps for you so I checked my gas cap. Yup, definitely was a little loose. Half/three quarters turn or so before click. Once home I cleared the codes and the engine light went off. However, both codes still show on my scanner as permanent every time I refresh it.

My question: Are the codes still popping up because my truck has to go through the EVAP cycle again? At that point the codes should drop off or the check engine light will come back on. Does that sound right? I put 15miles on my truck after clearing the light and that's about it.

What makes me nervous is that my left rear bed panel was replaced recently which is where a lot of the EVAP junk is. I also had my truck on a lift yesterday to get the repairs inspected and I wonder if they could have messed with something on accident..

I tried forcing an EVAP test with my OBDII scanner, but it doesn't look like the truck would accept it. Hopefully after a few drive cycles and cold soaks everything will show as normal.

 

Has the codes returned since you cleared them/check engine light on?...evaporative system is checked at key off

 

Check engine light has stayed off, but have only driven it like 15 miles since clearing.

Codes show on my scanner even after deleting them. They come right back as soon as I refresh.

My scanner has to have the key to the “on” position otherwise it won’t connect up. Just says “Test request sent successful” when I select the EVAP test. Maybe it’s not supported?

 

what kind of scanner you got?

 

These are probably tentative/pending codes, some codes require repeat occurrences to trigger the actual CEL.

 

Zurich ZR8s. Harbor freight special. Haven't used it much, but seems to always have done the job. Going to check to see if it needs an update.

 

Gotcha. I read on here somewhere that the EVAP test only happens under specific circumstances. Truck has to be off/cold for like 8hrs, certain idle time, drive speed, etc. I am hoping the next time it does it that the codes fall off. If the engine light comes back on then I will know I probably have bigger problems.

I bought a new OEM gas cap, but will wait to try it out. I want to give it a few days to see if the engine light comes back on first.

 

What do you use to clear codes? I usually use techstream to clear permanent codes on my 2012

 

Why was the panel replaced? If it was due to a accident it may have caused a line break in the filler area.

 

Yeah, that could be it. Although there was 3 instances of these two codes. I was able to delete two of three instances, but the one set of both codes always stays. I think @TACOTU3 may be right. These codes need repeat occurrences before they trigger the check engine light. I will keep checking to see if another instance shows up.

 

its that guy so that could be the problem.

 

Explains why there were three sets of these two codes when I first plugged in the reader. I was able to delete two of them, but one set always stays.

 

Old man who should not have been behind the wheel hit the back left corner of my truck. Maybe 10-15mph hit, but a big enough dent to replace the bed panel and not just try to pop it. My worry is something didnt get put back all the way on and it just came off. I dont smell any fuel at all from there. All connections looked good, but I am going to go back under there here in a bit.

 

I don't remember hearing a "click" when the guy put my gas cap back on. Then again its only one click for our Tacoma's so I could have easily missed it.

The engine light showed up two days and 30 miles later. Two 8hr+ long cold nights, some idling, mainly 45mph driving. Probably a few EVAP test/cycles in there which explains the 3 occurrences. Have more driving to do today. Will let it sit over night and let it idle tomorrow morning again for 5-10 min. Then I will check for the codes.

Edit: Appreciate all the quick responses.

 

Not familiar with this type. Could be some emulation issues while performing a function.
Check the regional thread for access to techstream.

 

Thats enough to break plastic. Could have a hairline fracture in a vent line or like you said, something was not reattached right. Knowing most of the evap system is down by the tank I would think it was out of harms way but the vent to the filler neck is not. Would be nice if you had a tool to run a evap test.

 

I think you are right about techstream and permanent codes. Found a few threads on these types of codes.

https://www.tacomaworld.com/threads/clearing-permanent-codes-emissions.511391/

https://www.tacomaworld.com/threads/obd-permanent-fault-code.625848/



And when i said early i was able to delete 2 of the 3 instances this is probably why:


Reading the two threads it sounds like i either need to do the drive cycle or use techstream.

Someone did mention putting the truck into check mode. Then maybe trying to delete it i guess?

Another post on tundra forum saying the same:

 

Based on my experience with 2012 car, permanent won't go away after numerous drive cycles. As I said, lots of folks in your area have access to techstream and probably would do it for a 6 pack.

 

I am not too worried about it so long the engine light never comes on. Don't have really strict emission testing here so wouldn't have to worry about them seeing that permanent code either (although it sounds like they wouldnt care about it being its usually the gas cap and the engine light hasnt popped back up). I imagine a metric ton of cars have this permanent code stored and most people dont even know.

If it really was the loose gas cap then I shouldn't see the engine light again. If my engine light does come back on soon then I will try the new OEM gas cap. If it still comes on after that then I know i have a bigger problem..