EVAP Code P0446

J

J

OCCUPY LoD :)
I truly hate issues like this. I have a Continuous Memory Code on my Evergreen car. I just need a direction. The car still has a miss on the #6 cylinder that is related to a damaged piston/valve (just did a leak down test and it won't hold pressure at all).

Here is what my AllData says:

HX18 - DTC P0446 OR P1450: Check For Visual Causes Of Excessive Fuel Tank Vacuum

Continuous Memory Diagnostic Trouble Code (DTC) P0446 or P1450 indicates that Self-Test has detected the Evaporative Emission Control System has excessive fuel tank vacuum. Also, a DTC P0446 indicates a vent control malfunction. Possible causes:
EVAP canister purge outlet tube (EVAP canister purge valve to EVAP canister) blockages or kinks.
EVAP canister tube (fuel tank to EVAP canister) blockages or kinks.
Fuel vapor elbow on EVAP canister contaminated.
Restricted EVAP canister.
Canister vent (CV) solenoid stuck closed (partially or fully).
Plugged or contaminated CV solenoid filter.
EVAP canister purge valve stuck open.
Fuel filler cap stuck closed (no vacuum relief).
VREF circuit open in fuel tank pressure (FTP) sensor.
Damaged FTP sensor.
Click to expand...
Which direction would you guys go? Keep in mind I have no testers and I already snagged a used gas cap from a Taurus at the junk yard.
 
G

ghost2

New member
P0446 is a major, major pain in the ass code. Many times it is simply the gas cap. However, it can also be the charcoal canister. In between these two are about 4 vsv sensors that can fail [these vsvs are sensors located in several spots under the hood]. If it produces a cell you have to just go one by one and each time cancel the CEL to see if comes back. Otherwise take the car to someone that can do a Smoke test to find a leak in the evap system. Or to the dealer for the use of their super diagnostic machine. {good luck there because they lie]. Good hunting.
 
J

J

OCCUPY LoD :)
Tempted to hit the dealer (in uniform)....I'll read over that site Charlie, thanks!
 
AnthraxBird

AnthraxBird

The Band, not the disease
Sorry to revive an old thread, but J, what happened? Did you ever get it fixxed? I just pulled a P0446, and I ran the EVAP self test with my scanner and its passing! Vent solenoid?
 
tixer

tixer

Lincoln Evangelist
He has a girlfriend now.. :D

I actually just talked to him on the phone about a month ago, so he's still around. just not /here/

I used to get this on my car once in a while. it seemed to coincide with the times a strong pressure differential was present when opening the gas cap, so I always assumed it was the emissions vent valve in the evap tray.

Interestingly enough, I haven't seen that error since I replaced my tray. Since I did not replace that valve, either the process of moving it to the new tray may have freed something up, or perhaps just the connector was dirty.

of course if that thing in the tray is not the vent valve, then I have no explanation. :)
 
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