Test A: DTC P0440: Small Leak Detected In EVAP System: Testing

WARNING: This page is about a different car, the 2002 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.

1) Visually Inspect Components For Small Leaks

DTC P0440 indicates less than 2.5 in. H₂ O (.625 kPa) bleed-up over a 15 second time period at 75 percent fuel fill. Vapor generation limit is more than 2.5 in. H₂ O (.625 kPa) over 120 seconds time. Check for presence of a fuel filler cap. DO NOT tighten or check for correct installation at this time. Verify canister vent control solenoid is correctly seated on EVAP canister. Check for cut or loose connections to fuel vapor hoses, tubes and connections in following locations: EVAP canister to EVAP canister purge valve, EVAP canister to fuel vapor vent valve assembly or fuel vapor tube assembly to fuel tank. Check fuel filler pipe for damage. Repair or install new components as necessary and go to next step. If hoses, tubes, connections and valves are okay, go to next step.

2) Check At EVAP Test Port For Small System Leaks

Complete EVAP emission system leak test. See EVAPORATIVE EMISSIONS SYSTEM LEAK TEST . If system passes leak test, go to next step. If system does not pass leak test, go to step 4).

3) Visually Inspect Fuel Filler Cap

Visually inspect fuel filler cap for damage. If fuel filler cap is damaged, replace fuel filler cap and go to next step. If fuel filler cap is okay, go to next step.

4) Check For Small Leaks At Fuel Filler Cap & EVAP Test Port

Connect EVAP Emission System Leak Tester (134-00056) to fuel filler pipe. Turn ignition on. Close canister vent control solenoid. See CANISTER VENT CONTROL SOLENOID CLOSING PROCEDURE . Pressurize EVAP system to 14 in. H₂ O (3.48 kPa). Using ultrasonic leak detector, check fuel filler cap and EVAP test port for leaks. If a leak is detected, repair or install new components as necessary and go to next step. If a leak is not detected, install fuel filler cap. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST . If system passes leak test, perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE .

5) Check For Concern Other Than Fuel Filler Cap

Refer to previous test results. If system passed EVAPORATIVE EMISSIONS SYSTEM LEAK TEST in step 2) , perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST . If system passes leak test, perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE . If system did not pass EVAPORATIVE EMISSIONS SYSTEM LEAK TEST in step 2) , replace fuel filler cap and go to next step.

6) Check For Small Leak With Tester Set At Fill Position

Connect EVAP Emission System Leak Tester (134-00056) to fuel filler pipe. Turn ignition on. Close canister vent control solenoid. See CANISTER VENT CONTROL SOLENOID CLOSING PROCEDURE . Open vacuum cut by-pass valve. Turn selector on EVAP emission system leak tester to FILL position. Pressurize EVAP system to 14 in. H₂ O (3.48 kPa). If pressure on EVAP system holds between 13.8-14.2 in. H₂ O (3.43-3.53 kPa), go to next step. If pressure on EVAP system does not hold between 13.8-14.2 in. H₂ O (3.43-3.53 kPa), discontinue pressurizing system and go to step 8).

7) Check For Leaks In Complete EVAP System

Connect EVAP emission system leak tester to EVAP test port. Turn ignition on. Close canister vent control solenoid. See CANISTER VENT CONTROL SOLENOID CLOSING PROCEDURE . Open vacuum cut by-pass solenoid. Pressurize EVAP system to 14 in. H₂ O (3.48 kPa). Using ultrasonic leak detector, check the following EVAP system locations:
- EVAP return tube to EVAP canister purge valve.
- EVAP canister purge valve to EVAP canister (canister vent control solenoid assembly).
- EVAP canister (canister vent control solenoid assembly to fuel tank).
- Fuel filler cap and fuel filler tube.
If a leak is detected at EVAP return tube, EVAP canister purge outlet tube or EVAP canister tube or associated hose, repair or install new components as necessary. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST . If system passes leak test, perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE . If no leak is detected at EVAP return tube, EVAP canister purge outlet tube or EVAP canister tube or associated hose, discontinue pressurizing system and go to next step.

8) Check For Small Leak From EVAP Return Tube To EVAP Canister

Disconnect fuel tank vapor tube at EVAP canister. Plug open end of EVAP canister. Connect EVAP emission system leak tester to EVAP test port. Turn ignition on. Close canister vent control solenoid. See CANISTER VENT CONTROL SOLENOID CLOSING PROCEDURE . Pressurize EVAP system to 14 in. H₂ O (3.48 kPa). Using ultrasonic leak detector, check EVAP system from intake manifold to EVAP canister vent control solenoid. If a leak is detected, repair or install new components as necessary. Repeat this step to verify leak is repaired and go to next step. If no leak is detected, open canister vent control solenoid and go to next step

9) Check For Small Leak Between Fuel Tank Vapor Tube & Fuel Tank Filler Pipe

Connect EVAP emission system leak tester to fuel filler pipe. Plug open end of EVAP canister outlet tube at EVAP Canister. Turn EVAP emission system leak tester selector to FILL position. Pressurize EVAP system to 14 in. H₂ O (3.48 kPa). Using ultrasonic leak detector, check fuel tank vapor tube to fuel tank, fuel tank and the fuel filler pipe for leaks. If no leak is detected, go to next step. If a leak is detected, repair or install new components as necessary. Repeat this step to verify leak is repaired. If a leak is still present, repair as necessary. If a leak is no longer present, go to next step.

10) Check EVAP System At Fuel Filler Pipe

Connect any disconnected tubes and connections. Perform EVAPORATIVE EMISSIONS SYSTEM LEAK TEST . If system passes leak test, restore system to normal operation and perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE . If system does not pass leak test, repair or install new components as necessary. Repeat this step to verify leak is repaired. Perform EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE .