Ford F150 Pickup. Instruction - part 1598

13) Check Repairs Between Fuel Tank & EVAP Canister 
 
Pressurize system to 14 in. H2O (3.48 kPa). Perform EVAPORATIVE EMISSIONS SYSTEM LEAK 
TEST. If system passes leak test (system pressure stays above 8 in. H2O (1.99 kPa), go to next step. If 
system does not pass leak test, go to step 12). 

14) Check For Fuel Tank Pressure Sensor Operation With Fuel Filler Cap Removed 
 
Ensure battery is fully charged. Remove fuel filler cap. Connect scan tool to Data Link Connector (DLC). 
Turn ignition switch to ON position. Using scan tool, access PCM FTP V PID from PID/DATA 
MONITOR & RECORD menu. If FTP V PID is 2.40-2.80 volts, go to next step. If FTP V PID is not 
within specification, replace fuel tank pressure sensor and repeat step 14) to verify repair. 

15) Check Fuel Tank Pressure Sensor With Pressure Applied 
 
Connect evaporative emissions system leak tester to fuel filler pipe. Disconnect and plug canister vent 
hose assembly. Turn ignition switch to ON position. Using scan tool, access FTP V PID from PID/DATA 
MONITOR & RECORD men. Pressurize system to 14 in. H2O (3.48 kPa). Turn ignition switch to OFF 
position. If FTP V PID was 4.22-4.90 volts, go to next step. If FTP V PID was not within specification, 
discontinue pressurizing EVAP system and return to step 14). 

16) Check EVAP Canister Purge Valve Operation 
 
Remove plug from canister vent hose assembly and reconnect EVAP return tube to intake manifold. Start 
engine and allow to idle. Using scan tool, access EVAPPDC and FTP V PIDs. Allow engine to stay 
running until PCM PID EVAPPDC reaches a duty cycle of 40 percent or more. If FTP V PID is less than 
2.6 volts (zero in. H2O), perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE 
CYCLE. If FTP V PID is not as specified, go to next step. 

17) Check For Intake Manifold Vacuum At EVAP Canister Purge Valve 
Disconnect input port vacuum hose and EVAP return tube from EVAP canister purge valve. Connect 
vacuum gauge to input port vacuum hose and plug open end of EVAP return tube. Start engine and allow 
to idle. Record vacuum measurement. Turn ignition switch to OFF position. Move vacuum gauge to 
EVAP return tube and plug input port vacuum hose. Start engine and allow to idle. Record vacuum 
measurement. 

If both measurements are 14-20 in. Hg (47.25-67.54 kPa), replace EVAP canister purge valve. Perform 
EVAPORATIVE EMISSIONS SYSTEM LEAK TEST. If system passes leak test, perform 
EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE. If both measurements are 
not as specified, check for blockages in input port vacuum hose or EVAP return tube. Check intake 
manifold vacuum lines or ports for blockage. Repair or replace components as necessary. Perform 
evaporative emissions system leak test. See EVAPORATIVE EMISSIONS SYSTEM LEAK TEST. 

F150 

NOTE:

At high elevations, intake manifold vacuum reading at input port vacuum 
hose and EVAP return tube must be 10 in. Hg (33. 77 kPa) or more.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

1) CHECK FOR DIAGNOSTIC TROUBLE CODE 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: 

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EVAP Canister Purge Valve  

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EVAP Canister  

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Fuel Vapor Vent Valve Assembly  

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Fuel Vapor Control Valve Tube Assembly (If Equipped)  

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. 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, go to step 6). 

4) CHECK FOR BLOCKAGE AT EVAP CANISTER VENT SOLENOID ASSEMBLY 
 
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. 

5) CHECK FOR BLOCKAGE BETWEEN THE EVAP TEST PORT AND THE FUEL TANK 
 
Connect Evaporative Emissions System Leak Tester (134-00056) to the fuel filler pipe. 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). Depress the Schrader valve in the 
evaporative emission test port. If pressure drops immediately, go to step 12). 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. 

6) CHECK FOR LARGE LEAK AT THE FUEL FILLER CAP 
 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

Connect Evaporative Emissions System Leak Tester (134-00056) to the fuel filler pipe. 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). Perform EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST. Using the ultrasonic leak detector, slowly check the fuel filler 
cap. If a leak is not detected, go to next step. If a leak is detected, install a new fuel filler cap. Repeat this 
step to verify repair. If no leak is detected, perform EVAPORATIVE EMISSION REPAIR 
VERIFICATION DRIVE CYCLE. 

7) CHECK FOR LEAK AT THE EVAP CANISTER AND CANISTER VENT SOLENOID 
 
Plug the canister vent hose assembly. Connect Evaporative Emissions System Leak Tester (134-00056) to 
the EVAP test port. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Using the ultrasonic leak detector, 
slowly check the EVAP canister and the canister vent solenoid. If a leak is not detected, go to next step. If 
a leak is detected, install new component(s) as necessary. Perform EVAPORATIVE EMISSIONS 
SYSTEM LEAK TEST. Perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE 
CYCLE. 

8) CHECK FOR LEAK BETWEEN THE EVAP TEST PORT AND THE EVAP CANISTER 
 
Disconnect the EVAP canister outlet tube from the fuel vapor control valve tube and plug the EVAP 
canister outlet tube. Connect Evaporative Emissions System Leak Tester (134-00056) to the fuel filler 
pipe. 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). Using the 
ultrasonic leak detector, slowly check the components from the EVAP return tube to the EVAP canister 
outlet tube. If a leak is detected, repair or install new fuel vapor hoses or tubes as necessary. After repairs, 
go to next step. If leak is not detected, go to step 10). 

9) CHECK REPAIRS BETWEEN THE EVAP TEST PORT AND THE EVAP CANISTER 
 
Reconnect all disconnected fittings. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST. 
If the system passes the leak test, go to step 12). If the system does not pass the leak test, go to next step. 

10) CHECK FOR LEAK FROM FUEL TANK TO EVAP CANISTER TUBE 
 
Transfer the plug from the EVAP canister outlet tube to the fuel vapor control valve tube. Connect 
Evaporative Emissions System Leak Tester (134-00056) to the fuel filler pipe. Pressurize EVAP system 
to 26-28 in. H2O (6.47-6.97 kPa). Using the ultrasonic leak detector, slowly check the following 
components for leaks: 

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Fuel filler pipe.  

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Fuel tank.  

z

Fuel vapor vent valve assembly.  

z

Fuel vapor control valve tube assembly.  

z

Fuel tank pressure sensor.  

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EVAP canister tube.  

z

Fuel vapor tube.  

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

If a leak is detected, repair or install new component(s) as necessary. After repairs, go to next step. If a 
leak was not detected, perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST. If no leak is 
detected, go to step 12). 

11) CHECK REPAIRS BETWEEN THE FUEL TANK AND THE EVAP CANISTER 
 
Reconnect all disconnected fittings. Pressurize EVAP system to 14 in. H2O (3.48 kPa). Perform 
EVAPORATIVE EMISSIONS SYSTEM LEAK TEST. If the EVAP system passes the leak test and 
system pressure stays above 8 in. H2O (1.99 kPa), go to next step. If the EVAP system does not pass the 
leak test, go to step 10). 

12) CHECK FOR FUEL TANK PRESSURE SENSOR OPERATION WITHOUT PRESSURE 
APPLIED 
 
Ensure the battery is fully charged. Disconnect the EVAP canister tube. Connect a scan tool to DLC 
connector. Turn ignition switch to ON position. Access PCM PID FTP V. If the PID FTP V reading is 
2.40-2.80 volts, go to next step. If the PID FTP V reading is not 2.40-2.80 volts, install a new fuel tank 
pressure sensor. Repeat this step to verify repair. 

13) CHECK FUEL TANK PRESSURE SENSOR WITH PRESSURE APPLIED 
 
Connect the EVAP canister tube. Connect Evaporative Emissions System Leak Tester (134-00056) to the 
fuel filler pipe. Turn ignition switch to ON position. Close canister vent solenoid. See CANISTER 
VENT SOLENOID CLOSING PROCEDURE. Access PCM PID FTP V. Pressurize EVAP system to 
14 in. H2O (3.48 kPa). Turn ignition switch to OFF position. If the FTP V PID reading is 4.22-4.90 volts, 
go to next step. If the FTP V PID reading is not 4.22-4.90, discontinue pressurizing the EVAP system. Go 
to step 12). 

14) CHECK EVAP CANISTER PURGE VALVE OPERATION WITH ENGINE AT IDLE 
 
Remove the plug and connect the EVAP return tube to the intake manifold. Turn ignition switch to ON 
position. Access PCM PID EVAPPDC and FTP V. Idle the engine until PCM PID EVAPPDC reaches a 
minimum of 40 percent duty cycle. Observe PID EVAPPDC and FTP V. If FTP V PID reads less than 
2.60 volts (0.0 inches H2O), perform EVAPORATIVE EMISSION REPAIR VERIFICATION 
DRIVE CYCLE. If FTP V PID does not read less than 2.60 volts (0.0 in. H2O), go to next step. 

15) CHECK FOR INTAKE MANIFOLD VACUUM AT THE EVAP CANISTER PURGE VALVE
Disconnect the input port vacuum hose and the EVAP return tube from the EVAP canister purge valve. 
Connect a vacuum gauge to the input port vacuum hose and plug the open end of the EVAP return tube. 
Start engine and allow to idle. Record the vacuum reading. Turn ignition switch to OFF position. Transfer 
the vacuum gauge to the EVAP return tube and plug the input vacuum hose. Start the engine and allow to 
idle. Record the vacuum reading. If both vacuum gauge readings were 14-20 in. Hg (47.25-67.54 kPa), 
install a new EVAP canister purge valve. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK 

NOTE:

At high elevations, the intake manifold vacuum source reading at both the 
input port vacuum hose and EVAP return tube must be at least 10 in. Hg 
(33.77 kPa).

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline