P0441
DTC P0441 Evaporative Emission Control System Incorrect Purge FlowMONITOR DESCRIPTION
DTC Detection Condition:
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
Monitor Result (Mode 06 Data):
The ECM tests the Evaporative Emissions (EVAP) system using the fuel tank pressure sensor, the Canister Close Valve (CCV), and the VSV for EVAP. The ECM closes the EVAP system and introduces a negative pressure (vacuum) into it. The ECM then monitors the internal pressure using the fuel tank pressure sensor (Refer to graphic).
The VSV for EVAP:
1. It is used to purge the evaporative emissions from the fuel tank into the intake manifold.
2. Works with the VSV for CCV to create a vacuum (negative pressure) inside the fuel tank, and perform leak tests.
Opening or closing malfunctions in the VSV for EVAP prompts the ECM to set DTC P0441.
The ECM checks for a VSV for EVAP "stuck closed" fault by commanding the VSV for EVAP open with the VSV for CCV (vent) closed. The fuel tank should develop a high negative pressure (vacuum). If negative pressure cannot be developed despite an OPEN command, the ECM determines the condition as a malfunction. Then, the ECM turns on the MIL and a DTC is set.
The ECM checks for a VSV for EVAP "stuck open" fault by commanding both the VSV for EVAP and VSV for CCV closed at a time when the fuel tank is at atmospheric pressure. If the fuel tank develops a high negative pressure (vacuum) during this early stage of the test, the ECM determines that the VSV for EVAP is "stuck open". The ECM will turn on the MIL and a DTC is set.
Wiring Diagram:
CONFIRMATION READINESS TEST
First Trip Procedure
a. The vehicle must be cold, and the ambient temperature must be approximately between 10 °C and 35 °C (50 °F and 95 °F).
b. The Intake Air Temperature (IAT) and the Engine Coolant Temperature (ECT) sensors have almost the same value.
c. Clear the DTCs.
- Disconnect the battery terminal or remove the EFI fuse for more than 60 seconds.
- Readiness tests will show "INCMPL" (incomplete).
d. Drive the vehicle on a freeway. Write down the state of the Readiness Tests. They will change to COMPL as the EVAP evaluation monitors operate and if the system passes. This procedure may take approximately 20 minutes or more.
NOTE: Do not shut off the engine - the results will be invalid.
Pass Condition - No Problem Found by the ECM
If the EVAP evaluation monitor shows "COMPL", go to the Non-Continuous Test screen.
NOTE: Do not shut off the engine - the results will be invalid.
- To get there, go to Advanced OBD II, On-board Tests, Non-continuous Tests.
- If all of the tests in the time $02 category show "Pass", the EVAP evaluation monitor has operated and no problem was detected.
Fail Condition - Problem Detected by the ECM
If the EVAP evaluation monitor shows INCMPL, go to the NonContinuous Test screen.
1. If all Tests show "Pass", the following may have occurred.
- The EVAP evaluation monitor did not operate.
- The EVAP evaluation monitor did not finish.
- The ECM withheld judgement.
2. If one or more of the tests in the time $02 category show "Fail", the EVAP evaluation monitor did operate and the ECM detected a problem.
3. Go to Continuous Tests screen. This is the only place DTC's are listed for the first trip.
NOTE: The DTC listed may not be valid. A second trip is needed to confirm the DTC.
Second Trip Procedure
a. The vehicle must be cold, and the ambient temperature must be approximately between 10 °C and 35 °C (50 °F and 95 °F).
b. Go to Readiness Tests screen.
c. Drive the vehicle on a freeway. Write down the state of EVAP evaluation monitor. This procedure may take approximately 20 minutes or more.
NOTE: Do not shut off the engine - the results will be invalid.
d. If Readiness Tests changes to "COMPL", the EVAP evaluation monitor has operated. Check for any stored DTC's.
- If a DTC has stored, the problem has been detected and confirmed by the ECM.
- If no DTC was found, the EVAP monitor operated but no problem was detected.
INSPECTION PROCEDURE
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Hand-held tester
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OBD II scan tool (excluding hand-held tester)
HINT:
- When using the hand-held tester, follow the procedures under the title "Hand-held tester".
- When using the OBD II scan tool, follow the procedures under the title "OBDII scan tool (excluding hand-held tester)" (See the procedures after the "Hand-held tester" procedures).
- Always troubleshoot DTCs P0441 (purge flow), P0446 (VSV for CCV), P0451, P0452 and P0453 (evaporative pressure sensor) before troubleshooting DTCs P0442 or P0456.
- As the customer the following questions:
1. Whether or not the fuel tank cap was loose and then tightened when the MIL came on.
2. Whether or not the fuel tank cap was loose when refueling.
If the fuel tank cap was loose, it caused the DTC to be output.
If the fuel tank cap was loose or the customer cannot remember, troubleshoot according to the procedures given.
- Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
- If the ENGINE RUN TIME in freeze frame data is less than 200 seconds, carefully check the vapor pressure sensor.
HINT: Use the chart to check the malfunction for each DTC output. Then perform the necessary repairs listed under "trouble chart".