P0441
P0441 - EVAP Purge System Performance
For wiring diagrams, refer to.
Theory of Operation
The EVAP purge monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. The monitor is a two stage test and runs only after the EVAP system passes the small leak test. Stage one is non-intrusive. The PCM monitors the purge vapor ratio and the ESM switch closed ratio. If the purge vapor ratio is more than a calculated value, the monitor passes. If the ESM switch closed ratio is greater than calculated value when purge flow is greater than a minimum value, the monitor passes. Stage two is an intrusive test and runs only if stage one does not pass. The PCM commands the purge solenoid to flow at a specified rate to force the purge vapor ratio to update. The ratio is compared to a calibrated specification. If the ratio is less than the specification, a one trip failure is recorded. This test can detect if the purge hose is off, obstructed, or the purge valve is not operational.
• When Monitored: With the engine running, after the EVAP system small leak test has passed.
• Set Condition: If the PCM detects that the purge vapor ratio and the ESM switch closed ratio are less than a calculated value, the PCM commands the purge solenoid to flow at a specified rate to update the purge vapor ratio. If the ratio remains less than a specified value, a one trip failure is recorded. Two trip fault. Three good trips to turn off the MIL.
• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - DTC is Active
• If P0443 is set along with this DTC, perform the diagnostic procedure for P0443 before continuing.
• Start the engine.
• Allow the engine to idle.
• Using the scan tool, perform the ESIM FORCED MONITOR TEST. Allow the test to complete.
• With a scan tool, select view DTCs.
• If any other DTC sets, active or pending, perform the diagnostic procedure for that DTC before proceeding with this test.
Is the status active for this DTC?
Yes
• Go to Test Step 2 => [ Test
Step 2 - EVAP System Inspection ]
No
• Perform the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC
Test Step 2 - EVAP System Inspection
Inspect the EVAP system for any of the following conditions:
• Holes or cracks.
• Loose seal points.
• Damaged or missing components.
• Incorrect routing of hoses and tubes.
• Loose or missing fuel cap.
• Damaged or missing fuel cap seal.
• Improper installation of the fuel cap.
• Damaged locking tabs on the fuel cap and/or filler tube.
• Damaged seal points on the fuel cap and/or filler tube.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 3 => [ Test
Step 3 - Insufficient Vacuum Supply To The Evap Purge Solenoid ]
Test Step 3 - Insufficient Vacuum Supply To The Evap Purge Solenoid
• Inspect the EVAP purge solenoid vacuum supply hose for proper routing and installation.
• Make sure the vacuum supply hose between the throttle body or intake manifold and the EVAP purge solenoid is free from any obstructions or blockage.
• Make sure the vacuum port at the throttle body or intake manifold is free from any obstructions or blockage.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 4 => [ Test
Step 4 - EVAP Purge Hose/Tube Obstruction ]
Test Step 4 - EVAP Purge Hose/Tube Obstruction
• Inspect the EVAP purge hose/tube for proper routing and installation between the EVAP purge solenoid and the fuel tank and between the fuel tank and the EVAP purge canister.
• Make sure the hose/tube is not damaged or kinked and is free from any obstructions or blockage.
Were any problems found?
Yes
• Repair or replace as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Go to Test Step 5 => [ Test
Step 5 - EVAP Purge Solenoid ]
Test Step 5 - EVAP Purge Solenoid
• Disconnect the purge lines at the EVAP purge solenoid.
• Using a hand vacuum pump, apply 10 in Hg of vacuum to the "CAN" side of the EVAP purge solenoid.
• The solenoid should hold vacuum for a minimum of 15 seconds.
• Turn the ignition ON.
• With the scan tool, actuate the evaporative purge valve solenoid duty cycle to the ON position.
• The vacuum should drop when the solenoid is actuated.
Does the solenoid function as described?
Yes
• Go to Test Step 6 => [ Test
Step 6 - PCM ]
No
• Replace the EVAP purge solenoid.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
Test Step 6 - PCM
• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EVAP purge solenoid and the PCM.
• Look for any chafed, pierced, pinched, or partially broken wires.
• Look for broken, bent, pushed out or corroded terminals.
• Refer to any technical service bulletins that may apply.
Were any problems found?
Yes
• Repair as necessary.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test
No
• Replace and program the PCM.
• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test