P0441

SYSTEM DESCRIPTION
The DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge diagnostic monitors the changes in the vacuum pressure in the fuel tank. The powertrain control module (PCM) will command the EVAP vent valve ON, CLOSED, and the vacuum pressure switching valve ON, OPEN, with the engine running. This allows engine vacuum into the entire EVAP system. The PCM continues to operate the purge valve until the vacuum has reached a specified limit, at which time the PCM commands the purge valve OFF, CLOSED. If the PCM detects the vacuum level was not achieved, or the vacuum level increased beyond the specified limit, a DTC P0441 will set.

CONDITIONS FOR RUNNING THE DTC
- The barometric pressure (BARO) is more than 75 kPa.
- The fuel level is between 25 and 75 percent.
- The ECT sensor and the intake air temperature (IAT) sensor are near the same temperature at engine start.
- The ECT sensor is at least 74°C (165°F) after engine warm up.

CONDITIONS FOR SETTING THE DTC
The pressure indicated in the EVAP canister and the fuel tank does not drop when the EVAP canister purge valve is ON.
OR:
The pressure indicated in the EVAP canister remains very low when compared to atmospheric pressure when the EVAP canister purge solenoid valve is OFF.

ACTION TAKEN WHEN THE DTC SETS
- The PCM illuminates the malfunction indicator lamp (MIL) after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.
- The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
- A DTC can be cleared by using the scan tool Clear Information function.

DIAGNOSTIC AIDS
- If DTC P0441 is the only EVAP DTC set, the most likely cause is an inoperable EVAP canister purge valve. Inspect the EVAP canister purge valve carefully for faulty connections and erratic operation.
- An intermittent malfunction may be caused by a fault in any of the EVAP solenoid electrical circuits. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions. Intermittent Conditions
- If the DTC cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.
- Operating the vehicle in Check Mode will increase the ability of the powertrain control (PCM) module to detect engine control system malfunctions. Refer to Check Mode in Service Bay Test Component Tests and General Diagnostics

TEST DESCRIPTION

Steps 1-2:

Steps 3-7:

Steps 8-10:

Steps 11-14:

Steps 15-20:

Steps 21-23:

The numbers below refer to the step numbers on the diagnostic table.
4. This step verifies the electrical operation of the EVAP canister purge solenoid.
5. This step tests the function of the EVAP canister purge solenoid.
8. This step uses the EVAP Purge/Seal function to test for the correct operation of the EVAP canister vent solenoid, the pressure switching solenoid, and the purge solenoid. Using the EVAP Purge/Seal function also tests for leaks by allowing the technician to seal the system and monitor the FTP sensor.
9. This step tests for a blockage or restriction in the EVAP canister vent valve and hoses. If the vacuum does not drop to less than -18.68 mm Hg (-10.0 inches H2O) after 30 seconds, there is a faulty condition in the EVAP vent system. The EVAP vent portion of the EVAP control system is diagnosed in DTC P0446.
21. This step uses the EVAP Purge/Seal function to test for the correct operation of the EVAP canister vent solenoid, the pressure switching solenoid, and the purge solenoid. Using the EVAP Purge/Seal function also tests for leaks by allowing the technician to seal the system and monitor the FTP sensor.