P0455, changed gas cap but still get code

[rtfm17]

I've been fighting with a stubborn P0455 that's still there even after replacing with an OEM gas cap.

If it's not the gas cap, what else can I check?

What conditions that trigger the PCM to do an EVAP test? Is there an easy way to trigger one (without just random driving, waiting & hoping)?

Thanks!

[Sleeper626]

what r we working on. that makes and big difference

[Asuna]

Yeah man liek what kind of car you running lol.

[rtfm17]

Doh!!! Sorry. Darn thing is making me crazy.

1999 Protege LX 1.6L.

Sine then I've also replaced the purge solenoid, used a hand vacuum pump to verify the line from intake manifold, vacuum chamber, and charcoal filter have zero leaks. So front to back is A-OK.

[Djlockjaw80]

Have you tried undoing the battery for 10 mintes to clear the codes?

[R2s99zoom]

Have you tried undoing the battery for 10 mintes to clear the codes?

I'm guessing theres an easier solution, like a fuse to pull for just a moment, w/out having side affects of resetting some stuff, like your radio presets, etc... (my '99 miata has a fuse i just pull for ~30 seconds to reset the computer)

[rtfm17]

I can clear the PCM, which clears the code & all onboard tests. (I have the autoenginuity OBDII package). That's no problem.

Problem I'm having is getting the PCM to actually *run*the EVAP test. I can't even tell if any work I did made it happy or not for several days.

I did get a service manual, and we've tried to reproduce 'mode 4', there is a cool-down cycle. It took 3 days to get it to trigger (and it promptly threw a P0455 again, arrrgh!)

(Manual also hints if I had a Mazda OEM scan tool (about $3-5k) there's probably a 'run test' button I could press...)

Any ideas? Suggestions? Magical incantations? ;-)

[Mazda_Tech]

i'd say you probably need a fuel filler neck.

[R-X-R]

ur problem is the sensor on the rear left underneath the tank.,..,