Pinpoint Test B: DTC P0455 Major Leak Or No Flow Detected Or DTC P1443 Very Small Or No Purge Flow Detected In System

WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Condition DTC P0455 set: -1.74 kPa (-7.0 inches H₂ O) over 30 seconds.

NOTE: Condition DTC P1443 set: -1.74 kPa (-7.0 inches H₂ O) over 30 seconds with more than 0.02 lb/min vapor flow.

B1 CHECK FOR DIAGNOSTIC TROUBLE CODE P0455 OR P1443
- Use the recorded results from the PCM DTCs.
- Is DTC P0455 present?
Yes

GO to B2.

No

GO to B3.
B2 VISUALLY CHECK FOR GROSS EVAP SYSTEM LEAKS
- Check for the presence of a fuel filler cap. Do not tighten or check for correct installation at this time.
- Check the input port vacuum and EVAP return tube are connected to the EVAP canister purge valve.
- Check that the canister vent solenoid is correctly attached to the EVAP canister.
- Check for disconnected or cracked fuel vapor hoses or tubes between the intake manifold and the following components:
  - EVAP canister purge valve
  - EVAP canisters
  - fuel vapor vent valve assembly
  - fuel tank vapor tube assembly
- Check for damaged fuel tank or fuel filler pipe.
- Is a concern with a hose, tube, connection or valve visually evident?
Yes

REPAIR or INSTALL new EVAP components as necessary. GO to B3.

No

GO to B3.
B3 CHECK FOR EVAP SYSTEM LEAKS
- Disconnect the EVAP return tube from the intake manifold and plug the EVAP return tube.
- Connect the Evaporative Emissions System Leak Tester to the EVAP test port.
- Carry out the evaporative emissions system leak test. Refer to EVAPORATIVE EMISSION SYSTEM LEAK TEST .
- Does the system pressure stay above 1.99 kPa (8 inches H ₂ O)?
Yes

GO to B4.

No

VERIFY that the fuel filler cap is installed correctly. REPAIR or INSTALL new components as necessary. CARRY OUT the evaporative emission system leak test. Refer to EVAPORATIVE EMISSION SYSTEM LEAK TEST . If the system passes the leak test, CARRY OUT the evaporative emission repair verification drive cycle Refer to EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE .
B4 CHECK FOR BLOCKAGE BETWEEN THE EVAP CANISTER PURGE VALVE AND FUEL VAPOR TEE
- Key in the ON position
- Close the canister vent solenoid Refer to CANISTER VENT SOLENOID CLOSING PROCEDURE .
- Pressurize the EVAP system to 3.48 kPa (14 inches H2O).
- Open the canister vent solenoid.
- Does the pressure drop immediately?
Yes

GO to B5.

No

INSTALL a new vapor line between the EVAP canister purge valve and the fuel vapor tee. CARRY OUT the evaporative emission system leak test. Refer to EVAPORATIVE EMISSION SYSTEM LEAK TEST . If the system passes the leak test, CARRY OUT the evaporative emission repair verification drive cycle. Refer to EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE .
B5 CHECK FOR BLOCKAGE BETWEEN FUEL FILLER PIPE AND THE FUEL VAPOR TEE
- Connect the Evaporative Emissions System Leak Tester to the fuel filler pipe.
- Pressurize the EVAP system to 6.47 to 6.97 kPa (26 to 28 inches H₂ O).
- Does the pressure drop immediately?
Yes

GO to B6.

No

INSTALL new fuel tank vapor line(s). REPEAT pinpoint test Step B5 to verify the repair. CARRY OUT the evaporative emission system leak test. Refer to EVAPORATIVE EMISSION SYSTEM LEAK TEST . If the system passes the leak test, CARRY OUT the EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE .
B6 CHECK FOR FAILED EVAP CANISTER PURGE VALVE OR FUEL TANK PRESSURE SENSOR
- Use the recorded results from the PCM DTCs.
- Are DTC codes P0455 and P1443 present?
Yes

INSTALL a new EVAP canister purge valve. Refer to EVAPORATIVE EMISSION CANISTER AND PURGE VALVE . CARRY OUT the evaporative emission system leak test. Refer to EVAPORATIVE EMISSION SYSTEM LEAK TEST . If no leak is detected, CARRY OUT the evaporative emissions repair verification drive cycle. Refer to EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE .

No

INSTALL a new fuel vapor control valve tube assembly, fuel tank pressure sensor. Refer to FUEL VAPOR CONTROL TUBE ASSEMBLY VALVE . CARRY OUT the evaporative emission system leak test. Refer to EVAPORATIVE EMISSION SYSTEM LEAK TEST . If the system passes the leak test, CARRY OUT the evaporative emission repair verification drive cycle. Refer to EVAPORATIVE EMISSION REPAIR VERIFICATION DRIVE CYCLE .