hello i was wondering if anyone can help me out with this my car has a check engine light and ive found the code P0455 EVAP system leak detected (large leak) ON 2 EVAP system ´ (See DTC P0455 ) wondering if any one nows this ive searched but only came up with the loose gas cap but im sure thats not the problem. i will still be searching for this but if anyone could help it would be appreciated.thanks in advance.

 

ive found an old thread helpfull yet still not sure the same problem but will try a few things https://www.rx8club.com/showthread.p...ighlight=po455

 

What makes you so sure it is not a faulty gas cap? That seems to be the most common cause of a evap error. Anyway, here's the shop manual sheet listing possible causes. You can start your troubleshooting.

 

gas cap should trigger the small evap leak detection code not the large. take it in you have probably a seal problem with the evap pump

 

There's a TSB/Recall on this - MSP13. It cites P0455 as being a symptom, and a new gas cap being the cure.

I got a P0455 a couple of months back. When I searched, I found the same posts that beechwoodRX8 would have found, and came away convinced that it was the gas cap. Since then I've put an extra second of attention into putting the cap on, and have not gotten another code.

Doesn't have to be the gas cap, of course. One of the threads that turned up was the poor guy who accidentally ran a screw into the evap system while installing audio stuff. $$$.

Beech - search MSP13, and see if your VIN falls into the affected range.

Ken

 

thanks for the help ...yeah i've checked all that i can yesterday but nothing seemed wrong or any leak. so what i did was erase the cel and filled up with gas and started to drive a lot today . i read somewhere in one of the threads to add some gas atleast 5 gallons in the tank and after driving let the evap system do its thing when you turn the car off test vacumm i believe..any way i drove for about 150 miles driving around town with many times being turned off and on again no light what so ever yet...i figured if it did had a leak or somthing really wrong the cel would come up again ...if it does come up the service at the dealer here are very cool in helping out...

 

The vaccuum test is small leak, 1 in of vaccumm to close a switch and it passes small leak. does this only is large/med leak passes. If it is not a gas cap (left off is the usual case of large leak) then you have a broken evap hose. very easy to find if you can get your car in the air. it has to fail 2 times to set the MIL.

 

I got the same problem as well, but my gas cap is tighten all the time..........

 

Also, when I fill out my full tank of gas, there is a click on the nozzel to stop the thing itself, right? After the nozzel stops itself, some gas tend to leak out from the hole......... is it a sign of the malfunction gas tank or the gas tank level dector or something, and that's what trigger the P0455 EVAP on my car??

 

KaKui: if the pump shuts off and gas is all the way up the filler neck to where its leaking out of the filler neck you most likely have spider webs in one of the filler neck's tubes, more common in miatas but ive seen it on all kinds of cars.

As for p0455, gross evap leak can be lots of things, true most of the time it's the gas cap, but it can also be a purge valve which mazda's are notorious for (ask any mazda 3 owner, guarantee theyve had it replaced, purge's set off 442,441,455, whole bunch)

there are updated gas caps depending on your year, and just visibly looking at a gas cap or hearing it click doesnt mean it's good. mazda has redesigned the o-ring, the threads on the cap, the sealing tightness all kinds of things that youd never even notice, theyre on the like 5th or 6th revision of these caps.

anywho, id rec. going to the dealer for a proper evap test, otherwise its all just guessing.

kevin.

 

The gas cap could be defective. That's why they did MSP13. If you're still under warranty, let the dealer check it out.

Fuel overflowing when you fill the tank is a separate issue. It's a combination of the car's filler neck and particular nozzles. I've learned to turn the pump down to the lowest speed when I'm within a couple of gallons of full. I think I've seen a couple of posts about there being a fix, but it hasn't been enough of an issue for me to worry about it. If some splashes out, I just wipe it off.

Ken

 

That's interesting. Any idea on how to test for that?

Ken

 

My Rx-8 is a 2007 GT, with 12,000km on it....... The engine light just keep on going on and off all the time. (Stays on for like 7-11 days, then turn off for 2 weeks, on and on) I am still under warranty, i better bring it to the dealer..........

Thanks,

 

no test, gotta pull the filler neck and check. easiest way is under the car remove the smaller hose and insert something like a wire snake see if there's any resistance or if spiders come out at you.

we had one miata with tons of spider eggs and babies in the neck, definitely one of the worst things to find while diagnosing and evap code lol. easy to fix tho and free.

kevin.

 

i had the same thing, buy a new gas cap from mazda- $9

 

Oh, new Mazda gas gap solves your problem?? Mine is 2007 Rx-8, is that new enough?

 

First thing is you gotta find is an old lady with a bird, cat, dog, goat, cow, and a horse. Here's the TSB procedure:

http://www.enchantedlearning.com/rhy.../Ladycow.shtml

 

Excellent! That link should be added to the FAQ.

Ken

 

I had booked service appointment from the dealer this saturday, I told them to check it's the EVAP system leak that makes the check engine light to stay on...... see what they find out from my 2007 Rx-8......

 

I'd agree had that CEL and got a new gas cap and problem was solved.

 

Right now mine keeps throwing P0455... although Ive reset it twice in the evening, and not gotten it when driving in the morning, but I get it immediately when I drive home in the afternoon/evening. Maybe since its warmer, it allows the leak to occur?

Does anyone know if the CEL should appear immediately if its the gas cap, or would that take a few minutes to pop up?

Im gonna try a gas cap since I have free 10$ off at the dealer, and then go from there since it sounds like that's the fix most of the time.

 

i have the same problem too and somtimes my oil light come on... theres oil and its not too low eitheer... im going to do a oil change this week hopefully it works....

 

I have the same code pop out (p0455). The thing is that i already got like a full tune up on my car and got it back in good condition, just last night i had my check engine light come on and when i scanned it, the code came in.i got it a new gas cap but i over read on some website that the gas cap has to be the original brand of the car? Is that true??

 

I've gotten that code on three occasions, a couple years apart on my 04.
Each time I replaced the gas cap (I always have it on all the way) and it always fixed it.
The last time it happened (last summer) I decided to go ahead and polish the rim of the filling port, in theory to help the o-ring keep a good seal and stay smooth.
We shall see how long this cap lasts.

 

The caps they sell at autozone will work, but I'm getting about 2 years out of them until I need a new one.
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