Connect leak tester to fuel filler pipe. Pressurize system to 14 in. H2O (3.48 kPa). If pressure drops
immediately, perform evaporative emissions system leak test. See EVAPORATIVE EMISSIONS
SYSTEM LEAK TEST . If system passes, perform DRIVE CYCLES in SELF-DIAGNOSTICS -
CNG, FLEX-FUEL & GASOLINE article. Ensure PENDING CODE CHECK & EVAP MONITOR
"BYPASS" CHECK is performed. If pressure does not drop immediately, replace fuel vapor vent valve.
Perform evaporative emissions system leak test. See EVAPORATIVE EMISSIONS SYSTEM LEAK
TEST . If system passes, perform DRIVE CYCLES in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article. Ensure PENDING CODE CHECK & EVAP MONITOR "BYPASS" CHECK is
performed.
LS & Thunderbird
1. Testing Evaporative Emission Running Loss System Monitor - Perform DRIVE CYCLES in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. Ensure PENDING CODE CHECK &
EVAP MONITOR "BYPASS" CHECK is performed. If PCM DTCs P0442, P0455, P1443 or P1450 are
retrieved, see EVAPORATIVE EMISSIONS DIAGNOSTIC TROUBLE CODE DEFINITIONS in
SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article for appropriate test procedure. If any
other PCM DTCs are retrieved, see DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article for appropriate test procedure. If no PCM
DTCs are retrieved, go to next step.
2. Evaporative Emission System Leak Test
Perform evaporative emissions system leak test. See EVAPORATIVE EMISSIONS SYSTEM LEAK
TEST . If system passes, go to next step. If system does not pass, go to step 9 .
3. Testing Fuel Tank Pressure Sensor Operation
Connect Evaporative Emissions System Leak Tester (134-00056) to fuel filler pipe. Turn ignition on.
Using scan tool, close canister vent solenoid. Select OUTPUT TEST MODE, FTP and FTP V PID. Select
ALL OFF mode. Press START button on scan tool to close canister vent solenoid. Pressurize system to
14 in. H2O (3.48 kPa). If FTP V PID is 4.22-4.90 volts, go to next step. If FTP V PID is not 4.22-4.90
volts, go to HISSING SOUND WHEN REMOVING FUEL CAP .
4. Testing Vent Portion Of EVAP System
Using scan tool, open canister vent solenoid. If pressure drops immediately, go to next step. If pressure
does not drop immediately, go to HISSING SOUND WHEN REMOVING FUEL CAP .
5. Testing Evaporative Emissions Test Port
Move EVAP tester to test port. Using scan tool, close canister vent solenoid. Pressurize system to 14 in.
H2O (3.48 kPa). If FTP V PID is 4.22-4.90 volts, evaporative emission system is operating normally. If
FTP V PID is not 4.22-4.90 volts, go to next step.
6. Testing Fuel Vapor Control Valve Tube
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE System & Component Testing - Gasoline