TEST. Perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE. If both
vacuum gauge readings were not 14-20 in. Hg (47.25-67.54 kPa), check for blockages in the input port
vacuum hose or the EVAP return tube. Check the intake manifold vacuum tree or port for debris. Repair
or install new component(s) as necessary. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK
TEST. Perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE.
LS & Thunderbird
1) Check For DTC P0455 Or P1443
If DTC P0455 is present, go to next step. If DTC P0455 is not present, go to step 3).
2) Visually Check For Gross EVAP System Leaks
Check for presence of a fuel filler cap. DO NOT tighten or check for correct installation at this time.
Ensure input port vacuum and EVAP return tube are connected to EVAP canister purge valve. Ensure
canister vent solenoid is properly seated on EVAP canister. Check for damaged fuel tank or fuel filler
pipe. Check for disconnected or cracked fuel vapor hoses or tubes between intake manifold and the
following components:
z
EVAP Canister Purge Valve.
z
EVAP Canister.
z
Fuel Vapor Vent Valve Assembly.
z
Fuel Vapor Control Valve Tube Assembly.
If no concerns are found, go to next step. If a concern was found, repair or replace component as
necessary and go to next step.
3) Check For EVAP System Leaks
Disconnect EVAP return tube from intake manifold and plug EVAP return tube. Connect Evaporative
Emissions System Leak Tester (134-00056) to EVAP test port. EVAP test port is located on EVAP
canister purge valve or on EVAP canister purge outlet tube near EVAP canister purge valve. Perform
EVAPORATIVE EMISSIONS SYSTEM LEAK TEST. If EVAP system pressure stays more than 8
in. H2O (1.99 kPa), go to next step. If EVAP system pressure drops to less than specification, verify fuel
filler cap is installed correctly. Repair or replace as necessary. Perform EVAPORATIVE EMISSIONS
SYSTEM LEAK TEST. When system passes, perform EVAPORATIVE EMISSION REPAIR
VERIFICATION DRIVE CYCLE.
4) Check For Blockage Between EVAP Canister Purge Valve & Canister Vent Solenoid
Turn ignition switch to ON position. Close canister vent solenoid. See CANISTER VENT SOLENOID
CLOSING PROCEDURE. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Open canister vent
solenoid. If pressure drops immediately, go to next step. If pressure does not drop immediately, perform
HISSING SOUND WHEN REMOVING FUEL CAP symptom test under EVAPORATIVE
EMISSION SYSTEM TESTS in SYSTEM & COMPONENT TESTING - GASOLINE article.
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline