Ford F150 Pickup. Instruction - part 1595

and fuel vapor vent valve for cuts or loose connections. Check fuel filler pipe for damage. If no concerns 
were found, go to next step. If concern was found, repair or replace component as necessary and go to 
next step. 

2) Check EVAP Test Port For Small System Leaks 
 
Disconnect and plug EVAP emission return tube at intake manifold. Perform EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST. If EVAP system does not pass leak test, go to step 4). If system 
passes leak test, go to next step. 

3) Visually Inspect Fuel Filler Cap 
 
Visually inspect fuel filler cap for damage. If fuel filler cap is okay, go to next step. If fuel filler cap is 
damaged, replace fuel filler cap and go to next step. 

4) Check For Small Leaks At Fuel Filler Cap & EVAP Test Port 
 
Connect Evaporative Emissions System Leak Tester (134-00056) to fuel filler pipe. Close canister vent 
solenoid. See CANISTER VENT SOLENOID CLOSING PROCEDURE. Pressurize EVAP system to 
14 in. H2O (3.48 kPa). While system is under pressure, use ultrasonic leak detector to check fuel filler 
cap and EVAP test port for leaks. If a leak is detected, repair or replace components as necessary and go 
to next step. If no leak is detected, reinstall fuel filler cap and perform EVAPORATIVE EMISSIONS 
SYSTEM LEAK TEST. When system passes, perform EVAPORATIVE EMISSION REPAIR 
VERIFICATION DRIVE CYCLE. 

5) Check For Concern Other Than Fuel Filler Cap 
 
Refer to previous test results. If EVAP system did not pass EVAPORATIVE EMISSIONS SYSTEM 
LEAK TEST performed in step 2), go to next step. If EVAP system passed EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST performed in step 2), repeat EVAPORATIVE EMISSIONS 
SYSTEM LEAK TEST. If system now passes leak test, perform EVAPORATIVE EMISSION 
REPAIR VERIFICATION DRIVE CYCLE. 

6) Check For Small Leak With Tester Set At Fill Position 
 
Connect evaporative emissions system leak tester to EVAP test port. Close canister vent solenoid. See 
CANISTER VENT SOLENOID CLOSING PROCEDURE. Set selector on evaporative emissions 
system leak tester to FILL position. Pressurize EVAP system to 14 in. H2O (3.48 kPa). If EVAP system 
pressure is 13.80-14.20 in. H2O (3.43-3.53 kPa), go to next step. If system does not hold pressure within 
specification, release pressure in EVAP system and go to step 8). 

7) Check For Leaks In Complete EVAP System 
 
Ensure evaporative emissions system leak tester is connected to EVAP test port. Close canister vent 
solenoid. See CANISTER VENT SOLENOID CLOSING PROCEDURE. Pressurize EVAP system to 
14 in. H2O (3.48 kPa). While system is under pressure, use ultrasonic leak detector to check the 
following EVAP system locations: 

 

2003 Ford Pickup F150 

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

  

z

EVAP Return Tube To EVAP Canister Purge Valve  

z

EVAP Canister Purge Valve To EVAP Canister (Canister Vent Solenoid Assembly)  

z

EVAP Canister (Canister Vent Solenoid Assembly) To Fuel Tank  

z

Fuel Filler Cap & Fuel Filler Tube  

If no leak is detected at any location, release pressure from EVAP system and go to next step. If a leak is 
detected at any location, repair or replace component as necessary. Perform EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST. When system passes, perform EVAPORATIVE EMISSION 
REPAIR VERIFICATION DRIVE CYCLE. 

8) Check For Small Leak Between EVAP Return Tube To Fuel Vapor "T" Fitting 
 
Disconnect EVAP canister purge outlet tube at fuel vapor "T" fitting. Plug opening in EVAP canister 
purge outlet tube. Connect evaporative emission system leak tester to EVAP test port. Pressurize EVAP 
system to 14 in. H2O (3.48 kPa). While system is under pressure, use ultrasonic leak detector to check 
EVAP system from intake manifold to EVAP canister purge outlet tube. If no leak is detected, go to next 
step. If leak is detected, repair or replace component as necessary. Repeat step 6) to verify repair and go 
to next step. 

9) Check For Small Leak Between EVAP Canister & Fuel Filler Pipe 
 
Connect evaporative emission system leak tester to fuel filler pipe. Transfer plug from EVAP canister 
purge outlet tube to fuel vapor "T" fitting. Set selector on evaporative emissions system leak tester to 
FILL position. Close canister vent solenoid. See CANISTER VENT SOLENOID CLOSING 
PROCEDURE. Pressurize EVAP system to 14 in. H2O (3.48 kPa). While system is under pressure, use 
ultrasonic leak detector to check fuel vapor control valve tube to fuel tank for leaks. Check fuel tank 
pressure sensor, fuel vapor control valve tube and fuel filler pipe. Check fuel tank to EVAP canister 
(canister vent solenoid). If no leak is detected, go to next step. If any leak is detected, repair or replace 
component as necessary and go to next step. 

10) Check EVAP System At Fuel Filler Pipe 
 
Reconnect EVAP canister purge outlet tube to fuel vapor "T" fitting. Perform EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST. If EVAP system passes leak test, perform EVAPORATIVE 
EMISSION REPAIR VERIFICATION DRIVE CYCLE. If EVAP system did not pass leak test, 
repeat step 6).  

LS & Thunderbird 

1) Visually Inspect Components For Small Leaks 
 
Check for presence of fuel filler cap, but DO NOT tighten or check for proper installation at this time. 
Ensure canister vent solenoid is fully seated on EVAP canister. Check EVAP hoses between EVAP 
canister and EVAP canister purge valve, fuel vapor control valve tube and fuel tank, and EVAP canister 
and fuel vapor vent valve for cuts or loose connections. Check fuel filler pipe for damage. If no concerns 
were found, go to next step. If concern was found, repair or replace component as necessary and go to 

 

2003 Ford Pickup F150 

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

  

next step. 

2) Check At The EVAP Test Port For Small System Leaks 
 
Disconnect and plug EVAP emission return tube at intake manifold. Perform EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST. If EVAP system does not pass leak test, go to step 4). If system 
passes leak test, go to next step. 

3) Visually Inspect Fuel Filler Cap 
 
Visually inspect fuel filler cap for damage. If fuel filler cap is okay, go to next step. If fuel filler cap is 
damaged, replace fuel filler cap and go to next step. 

4) Check For Small Leaks At Fuel Filler Cap & EVAP Test Port 
 
Connect Evaporative Emissions System Leak Tester (134-00056) to fuel filler pipe. Close canister vent 
solenoid. See CANISTER VENT SOLENOID CLOSING PROCEDURE. Pressurize EVAP system to 
14 in. H2O (3.48 kPa). While system is under pressure, use ultrasonic leak detector to check fuel filler 
cap and EVAP test port for leaks. If a leak is detected, repair or replace components as necessary and go 
to next step. If no leak is detected, reinstall fuel filler cap and perform EVAPORATIVE EMISSIONS 
SYSTEM LEAK TEST. When system passes, perform EVAPORATIVE EMISSION REPAIR 
VERIFICATION DRIVE CYCLE. 

5) Check For Concern Other Than Fuel Filler Cap 
 
Refer to previous test results. If EVAP system did not pass EVAPORATIVE EMISSIONS SYSTEM 
LEAK TEST performed in step 2), go to next step. If EVAP system passed EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST performed in step 2), repeat EVAPORATIVE EMISSIONS 
SYSTEM LEAK TEST. If system now passes leak test, perform EVAPORATIVE EMISSION 
REPAIR VERIFICATION DRIVE CYCLE. 

6) Check For Small Leak With Tester Set At Fill Position 
 
Connect evaporative emissions system leak tester to EVAP test port. Close canister vent solenoid. See 
CANISTER VENT SOLENOID CLOSING PROCEDURE. Set selector on evaporative emissions 
system leak tester to FILL position. Pressurize EVAP system to 14 in. H2O (3.48 kPa). If EVAP system 
pressure is 13.80-14.20 in. H2O (3.43-3.53 kPa), go to next step. If system does not hold pressure within 
specification, release pressure in EVAP system and go to step 8). 

7) Check For Leaks In Complete EVAP System 
 
Ensure evaporative emissions system leak tester is connected to EVAP test port. Close canister vent 
solenoid. See CANISTER VENT SOLENOID CLOSING PROCEDURE. Pressurize EVAP system to 
14 in. H2O (3.48 kPa). While system is under pressure, use ultrasonic leak detector to check the 
following EVAP system locations: 

z

EVAP Return Tube To EVAP Canister Purge Valve  

z

EVAP Canister Purge Valve To EVAP Canister (Canister Vent Solenoid Assembly) 

 

2003 Ford Pickup F150 

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

  

z

EVAP Canister (Canister Vent Solenoid Assembly) To Fuel Tank  

z

Fuel Filler Cap & Fuel Filler Tube  

If no leak is detected at any location, release pressure from EVAP system and go to next step. If leak is 
detected at any location, repair or replace component as necessary. Perform EVAPORATIVE 
EMISSIONS SYSTEM LEAK TEST. When system passes, perform EVAPORATIVE EMISSION 
REPAIR VERIFICATION DRIVE CYCLE. 

8) Check For Small Leak Between EVAP Return Tube To Fuel Vapor Control Valve Tube 
 
Disconnect fuel vapor control valve tube from under vehicle fuel supply and vapor tube assembly. Plug 
open end of under vehicle fuel supply and vapor tube assembly. Connect evaporative emission system 
leak tester to EVAP test port. Pressurize EVAP system to 14 in. H2O (3.48 kPa). While system is under 
pressure, use ultrasonic leak detector to check EVAP system from intake manifold to plugged end of 
under vehicle fuel supply and vapor tube assembly. If no leak is detected, go to next step. If leak is 
detected, repair or replace component as necessary. Repeat step 6) to verify repair and go to next step. 

9) Check For Small Leak Between EVAP Canister & Fuel Filler Pipe 
 
Connect evaporative emission system leak tester to fuel filler pipe. Transfer plug from under vehicle fuel 
supply and vapor tube assembly to fuel vapor control valve tube. Set selector on evaporative emissions 
system leak tester to FILL position. Close canister vent solenoid. See CANISTER VENT SOLENOID 
CLOSING PROCEDURE. Pressurize EVAP system to 14 in. H2O (3.48 kPa). While system is under 
pressure, use ultrasonic leak detector to check fuel vapor control valve tube to fuel tank for leaks. Check 
fuel tank pressure sensor, fuel vapor control valve tube and fuel filler pipe. Check tubes from fuel tank to 
EVAP canister and to canister vent solenoid. If no leak is detected, go to next step. If any leak is detected, 
repair or replace component as necessary and go to next step. 

10) Check EVAP System At Fuel Filler Pipe 
 
Reconnect fuel vapor control valve tube to under vehicle fuel supply and vapor tube assembly. Perform 
EVAPORATIVE EMISSIONS SYSTEM LEAK TEST. If EVAP system passes leak test, perform 
EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE. If EVAP system did not 
pass leak test, repeat step 6).  

Ranger 

1) Visually Inspect Components For Small Leaks 
 
Check for presence of fuel filler cap, but DO NOT tighten or check for proper installation at this time. 
Ensure canister vent solenoid is fully seated on EVAP canister. Check EVAP hoses between EVAP 
canister and EVAP canister purge valve and EVAP canister and fuel vapor vent valve for cuts or loose 
connections. Check fuel filler pipe for damage. If no concerns were found, go to next step. If concern was 
found, repair or replace component as necessary and go to next step. 

2) Check EVAP Test Port For Small System Leaks 
 

 

2003 Ford Pickup F150 

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