EVAP Canister Code

[stir_fry_boy]

Hey guys got a EVAP canister code - malfunction, and I don't know the code number but it is a California car and wondered what it could be. Any help would be appreciated. Got it cleared going to drive it to see what it does. It is a 98 Cam XLE V6 with California Emissions. Mileage is 138k.

[Gary_602Z]

Could be Evap cannister or a vacum line off/cracked/loose. The code would help also!

Gary

[stir_fry_boy]

After looking at the vacuum lines, they look good, had the code cleared, didn't get the number but it hasn't come on in almost 100 miles. I think that it may be the vacuum pressure sensor, as I think the code was a malfunction with that. I looked at the Chilton book, and that is what it said. I will get the code tonight. There is only one EVAP canister code - malfunction on the list. But I don't know how much that sensor would be. Do I need to clean the canister out?

[stir_fry_boy]

Bump . . . . . .

[Gary_602Z]

I think the canister is a sealed unit . Probably no cleaning.

Gary

[BadChicken]

P0440 Evaporative Emission Control System Malfunction
P0441 Evaporative Emission Control System Incorrect Purge Flow
P0442 Evaporative Emission Control System Leak Detected (Small Leak)
P0443 Evaporative Emission Control System Purge Control Valve Circuit Malfunction
P0444 Evaporative Emission Control System Purge Control Valve Circuit Open
P0445 Evaporative Emission Control System Purge Control Valve Circuit Shorted
P0446 Evaporative Emission Control System Vent Control Circuit Malfunction
P0447 Evaporative Emission Control System Vent Control Circuit Open
P0448 Evaporative Emission Control System Vent Control Circuit Shorted
P0449 Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction
P0450 Evaporative Emission Control System Pressure Sensor Malfunction
P0451 Evaporative Emission Control System Pressure Sensor Range/Performance
P0452 Evaporative Emission Control System Pressure Sensor Low Input
P0453 Evaporative Emission Control System Pressure Sensor High Input
P0454 Evaporative Emission Control System Pressure Sensor Intermittent
P0455 Evaporative Emission Control System Leak Detected (Gross Leak)

Usually the codes will come in a pair or a set of 3 when the light is tripped

[Maim Menu]

I've had a P0446 (only) on my car for about a month now, it comes and go.

[stir_fry_boy]

Its a P0450 code. That is the only one. Just one code.

[idontspeed]

that fault is for the vapor pressure sensor circuit.

basically a sensor that switches between measuring pressure in the canister and tank. The sensor sometimes gets some carbon dust, which causes it to stick in one position. I had this problem once (but set a po460) and everything checked out OK. I'm sure that running the tests "freed" up the sensor so that it can switch back and forth.

I'm not sure if this part can be replaced seperately. Usually that and/or the canister purge vsv are built into the charcoal canister.

[Maim Menu]

I checked my engine again today and noticed something :

Attached to the top of the big intake hose is the EVAP hose, and it plugs itself on top of the throttle body. That hose makes a fast paced tsh-tsh-tsh-tsh-tsh sound when on Idle. If I press the hose the engine goes down a bit and the tsh-tsh-tsh stops.

I know there's supposed to be a vacuum through that hose when the engine is running. But isn't a sound coming from that hose an indicator of a plugged hose or vacuum leak? I searched carefully around by following the hose and found no air rushing out of anything. It drives me crazy since the sound is very crisp and in-your-face going tsh-tsh-tsh but I can't find a leak nowhere. I want to unplug that hose from the TB to verify the vacuum but before I go into this :

Anybody else's car doing the same sound? My trouble code is P0446 Evaporative Emission Control System Vent Control Circuit Malfunction