Test A: DTC P0442: Small Leak Detected In EVAP System: LS

WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 2001 Mercury Sable, 2001 Mercury Mountaineer, 2001 Mercury Grand Marquis, 2001 Mercury Cougar, and 2001 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.

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 problems were found, go to next step. If problem 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. H₂ O (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 DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Ensure PENDING CODE CHECK & EVAP MONITOR "BY-PASS" CHECK is performed.

5) Check For Problem 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 DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Ensure PENDING CODE CHECK & EVAP MONITOR "BY-PASS" CHECK is performed.

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. H₂ O (3.48 kPa). If EVAP system pressure is 13.80-14.20 in. H₂ O (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. H₂ O (3.48 kPa). While system is under pressure, use ultrasonic leak detector to check the following EVAP system locations:
- EVAP Return Tube To EVAP Canister Purge Valve
- EVAP Canister Purge Valve To EVAP Canister (Canister Vent Solenoid Assembly)
- EVAP Canister (Canister Vent Solenoid Assembly) To Fuel Tank
- 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 DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Ensure PENDING CODE CHECK & EVAP MONITOR "BY-PASS" CHECK is performed.

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. H₂ O (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. H₂ O (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 DRIVE CYCLE PROCEDURES under ADDITIONAL SYSTEM FUNCTIONS. Ensure PENDING CODE CHECK & EVAP MONITOR "BY-PASS" CHECK is performed. If EVAP system did not pass leak test, repeat step 6).