OBD code P0446 ('97 5.4L)
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Junior User
Joined: Jan 2010
Posts: 61
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From: Woburn, MA
OBD code P0446 ('97 5.4L)
I just bought a '97 Ford E-150 w5.4L and the code P0446 is coming on and preventing me from getting an inspection stickr (in Massachusetts). The code definition says it's related to the "vapor canister purge valve". Where is this located? And could it just be a loose or broken vacuum line? Has anybody else had this problem?
And I've been seeing ALOT of posts for issues with plugs blowing out on these motors, mine has 150K+ miles and seems to run like a champ, should I be concerned?
Thanks
And I've been seeing ALOT of posts for issues with plugs blowing out on these motors, mine has 150K+ miles and seems to run like a champ, should I be concerned?
Thanks
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
This will give you the laundry list. If you've been mudding lately, check the EVAP canister vent hose to see if it's clogged with mud. The canister is under the bed near the spare tire.
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.
Note: If the EVAP canister-CV solenoid and fuel tank assemblies are not accessible to perform the following step, GO to the Powertrain/Engine Group, Evaporative Emissions Section in the Workshop Manual for removal procedures.
Check for kinks or bends in the fuel vapor hoses/tubes (EVAP canister purge outlet tube and EVAP canister tube).
Visually inspect EVAP canister inlet port, CV solenoid filter and canister vent hose assembly for contamination or debris.
Check CV solenoid filter for blockage or contamination.
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.
Note: If the EVAP canister-CV solenoid and fuel tank assemblies are not accessible to perform the following step, GO to the Powertrain/Engine Group, Evaporative Emissions Section in the Workshop Manual for removal procedures.
Check for kinks or bends in the fuel vapor hoses/tubes (EVAP canister purge outlet tube and EVAP canister tube).
Visually inspect EVAP canister inlet port, CV solenoid filter and canister vent hose assembly for contamination or debris.
Check CV solenoid filter for blockage or contamination.
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
Missed the "E" so I assumed "F". The systems are the same, though.
We've had reports of spiders and wasps making nests in the vent hose, so there are certainly other causes of the hose getting clogged.
The evaporative emissions system is tough to diagnose without special equipment. Good luck with it.
We've had reports of spiders and wasps making nests in the vent hose, so there are certainly other causes of the hose getting clogged.
The evaporative emissions system is tough to diagnose without special equipment. Good luck with it.
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