Po455

[Billy Blaze]

Hey guys, I searched for code PO455 and couldnt find anything in this section.
Anyone remember off hand the fix for this code?
PO455 = Evaporative Emission System Leak.

Thanks!

[Billy Blaze]

Found this on the pointy board...
I think I will try a new Gas cap and some Seafoam in the tank and intake manifold first, I remember my old 99 responded very well to a good fogging...


Your cel is typical problem of 99-2000 model's. As you have undoughtedly read in this forum, many have spent a lot of money chasing it. My belief is that it is caused by a dirty fuel system, more specific a dirty fuel pressure regulator. The fuel pressure regulator is mounted in the tank next to the fuel pump. The fuel is only filtered by a mesh screen before it's pumped thru the regulator. The regulator is a simple spring-ball device that when it becomes dirty will not allow for adjustment of pressure depending on demand of engine for fuel. Because of this, the computer thru various sensors trys unsuseccessfully to compensate and you end up with a cel. If not corrected, the problem can increase and will cause expensive damage. Mazda has a service bulliten to test the fpr, but it only tests for leak down which only ocurs in some of the more advanced cases. Using fuel system/injector cleaner will clear up the problem temporarly, changing the fpr will clear up the problem for a longer time, but unless you remove the fpr from inside the tank and install an aftermarket fpr after the fuel filter outside the tank with a return line, simulair to earlier models, the problem will reocur. Bob.

[Titus]

Isn't that the code that is thrown if the gas cap is bad or not screwed on tight? I'd start with a cheap and easy new gas cap before messing with the FPR.

[Billy Blaze]

Yep

[SilverToy]

If you like, do the gas cap first and I'll come by and clear the code, you can drive it for a few days and see what happens.

[Billy Blaze]

Thanks man!
But I have put off buying a code reader for years and finally broke down and got one.
I cleared it today when I got the code, I cranked and ran the car and didnt come back on.
I unscrewed the gas cap and put it back on first.
I'm not much worried about it just wanted to know what it was.
I figured it was some little something because the car runs great! :)

[cam76034]

I've had the same code on my 99 for awhile now. Just for grins I cleared the code and put on a gas cap from an NA but it came back several days later. Which makes me wonder what the difference is, if any, in the gas caps between the NA's and the NB's? Is there something different in the design? I've got till May to get it figured out before inspection time rolls around.

[Sharpie]

My buddy with a 92' stopped by last night and asked to borrow my gas cap because his failed at his inspection. I hope it passes today. I didn't notice any difference using his on the way to work.

[Billy Blaze]

mine hasnt come back yet ; )

[cam76034]

Give it time...

[Billy Blaze]

LOL how you been Cam? I miss seeing you guys, hope you all are well