P1441

Diagnostic Chart:

Emission Hose Routing Diagram:

SYSTEM DESCRIPTION
THE POWERTRAIN CONTROL MODULE (PCM) supplies a ground to energize the EVAP purge valve and turn the purge on. The EVAP purge valve control is pulse width modulated (PWM) or turned on and off several times a second. The duty cycle - or pulse width - is determined by engine operating conditions including load, throttle position, coolant temperature and ambient temperature. The duty cycle is calculated by the PCM and the output is commanded when the appropriate conditions have been met. The system checks for conditions that cause the EVAP system to purge continuously by commanding the EVAP vent valve ON, which closes the vent valve, and the EVAP canister purge valve OFF, which closes the purge valve. If the vacuum level in the fuel tank increases during the test, a continuous purge flow condition is indicated.

The following conditions will set a DTC P1441.
^ EVAP canister purge valve leaking internally.
^ EVAP purge and engine vacuum lines switched at the EVAP canister purge valve.
^ EVAP canister purge valve control circuit grounded.

CONDITIONS FOR RUNNING THE DTC
All of the conditions for DTC P0440, P0442 and P0446 diagnostic tests have been met and passed.

CONDITIONS FOR SETTING THE DTC
A continuous open purge flow condition is detected during the diagnostic test by a drop in the fuel tank pressure to less than -11 in H2O.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.
^ The PCM stores the conditions that were present when the DTC set as Freeze Frame/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the MIL OFF during the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC clears when the PCM turns OFF the MIL.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
Check for the following conditions:
^ Incorrect vacuum line routing - Verify that the source vacuum line routing to the EVAP purge valve is correct and that the EVAP purge and source vacuum lines to the EVAP canister purge valve are not switched.
^ A malfunctioning or damaged canister - Inspect for carbon release in the EVAP system.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

If the harness appears to be OK, connect the J41413 EVAP Pressure/Purge Diagnostic Station to the EVAP service port, pressurize the EVAP system to 10 in. H2O and observe the Fuel Tank Pressure parameter on the scan tool while moving connectors and wiring harnesses related to the EVAP purge valve. A sudden change in the display will indicate the location of the malfunction.

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection.
Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Diagrams.
^ Damaged harness.
Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display may indicate the location of the fault. Refer to Circuit Testing and Wiring Repairs in Diagrams.
^ Inspect the PCM and the engine grounds for clean and secure connections.

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
Numbers below refer to the step numbers on the Diagnostic Table:
1. The Powertrain On Board Diagnostic (OBD) System Check prompts you to complete some basic check and store the Freeze Frame and Failure Records data in the scan tool if applicable.