2004 Toyota Avalon with 175k miles. Check engine light came on yesterday.(first time ever) I went to Auto Zone to use their OBD scanner and it diagnosed that the problem is the gas cap. They have a Duralast for $10. The Toyota Dealership quoted $38 for OEM. I know that with some parts OEM is better or even necessary for proper function. Which would you boys recommend? Thanks
get the oem from toyota then you know if its the cap or not? also take a close look at oem compared to the ones at auto parts stores the material the seal is made of is much higher quality then a cheap 10 gas cap... I assure you Scotty would tell you to get oem... you can get one on amazon or walmart for 28.00
@thdesha You present a compelling argument for OEM. I was beginning to think along that same line of reasoning especially your statement that by purchasing a genuine Toyota part I would know if it’s the cap or not. Thank you for your input.
I went to Auto Zone to use their OBD scanner and it diagnosed that the problem is the gas cap
What was the actual code? Probably the evap system. Gas cap is a common and inexpensive cause but certainly not the only one on a 21-year-old car. Remember, in the vast majority of cases a scan tool does not tell you what part to replace, it flags a condition that can have multiple different causes.
@chucktobias Thank you for your response Chuck. The code is P0442 which is, as you probably know, Evaporative Emission Leak Detected (small leak) which I just learned when I returned home and looked online. Among other causes listed are: - a faulty evap system vent valve, - a blockage in the evap system, - a leak in the evap system, - a malfunctioning fuel tank pressure sensor, etc. When I as at AutoZone I wondered how their computer could specifically identify the fuel cap as the culprit. Perhaps it is the only part that they have in stock for this car. But now knowing that the fuel cap could be a possible cause of a P0442, it seems to be a good place to begin. So I am wanting to learn if you have an opionion or experience with an aftermarket cap (the Duralast, in this case) functioning properly so as to properly seal the fuel tank fill neck or if you would recommend an OEM replacement. Thanks
I have not used Duralast gas caps but have used Stant replacements which worked well. OEM is probably better quality but a gas cap is not as complex as something like an O2 or MAF sensor and doesn't have to interface with computer modules - it just has to have a good seal.
@chucktobias Thank you for your additional comments.
@chucktobias Hey Chuck. Is there a way to contact you privately on this forum?
No, we don't have a private messaging facility here. Even if a post as marked as "private" all moderators and administrators can see it, there's no way to direct it only to a specific person.
@chucktobias Okay, so how could I send a “private” message to the moderators and administrators? Thanks.
I've been informed by management that there is really no way to do that.
I'm using an aftermarket gas cap from O'Reillys. Bought it several years ago and it's still fine.
@hixster Thanks Hixster
@avalon04 Mine cap cost $11 or $12 and has a tether.. a gas cap keeps the seal or it doesn't.
@hixster "a gas cap keeps the seal or it doesn't."
Thanks for that. For some reason I thought that they had a valve in ther center that would release excess pressure in the fuel tank and that yu woud need one properly calibrated for a specific vehicle. And I thought perhaps that was the reason that a Toyota OEM cost almost $40. So if I compare the current OEM cap with an aftermarket and the seal gasket thickness and overall diameter is the same then it should provide a proper seal and I should be good to go.
If the OEM one lasted 20 years then I would get that again
@imperator Thanks for your response MMJ. Actually my current fuel cap is OEM but not the original. I think It was about 12 years ago when I replaced the original when I left it on my trunk lid while re-fueling and drove off without it. Yeah....I know.
I suppose more specifically I was wanting to learn whether the Duralast fuel cap from AutoZone would function properly, excluding considerations of longevity/durablity.
Don’t know sorry. My caps were always tethered so I never lost them
Here's what I experienced: I was getting CELs with increasing frequency with codes suggesting gas cap issues. Finally the CEL would not go away no matter what I did. I then got some generic $18 cap at an auto parts store, which fixed the problem for about a month.
When the CEL resumed I said "phukit" got the OEM version. That fixed the problem permanently.
