P1441

Diagnostic Chart:

Emission Hose Routing Diagram:

SYSTEM DESCRIPTION
THE P0WERTRAIN CONTROL MODULE (PCM) supplies a ground to energize the EVAP purge valve (purge on). The EVAP purge valve control is Pulse Width Modulated (PWM) or turned on and off several times a second. The duty cycle (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 (Closed) and the EVAP canister purge valve OFF (Closed). If vacuum level in the fuel tank increases during the test, a continuous purge flow condition is indicated. This can be caused by any of the following conditions:

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 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 (fuel tank pressure decreases to less than -11 in. H2O.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear 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.
^ 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 that caused the DTC to set occurs. This may assist in diagnosing the condition.

If the harness appears to be OK, connect the J 41413 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 Diagrams for diagnosis and repair.
^ 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 scan tool display may indicate the location of the fault. Refer to Diagrams for diagnosis and repair.
^ 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 of the basic check and store the Freeze Frame and Failure Records data on the scan tool if applicable.