P1441
DTC P1441 EVAP System Flow During Non-Purge
The evaporative system as defined by federal regulation includes the following components:
- Fuel tank
- EVAP canister vent solenoid
- Fuel tank pressure sensor
- Fuel pipes and hoses
- Vapor lines
- Fuel cap
- Evaporative emission (EVAP) canister
- Purge lines
- EVAP canister purge solenoid
The EVAP purge solenoid valve allows manifold vacuum to purge the canister. The Powertrain Control Module (PCM) supplies a ground to energize the solenoid valve (purge ON). The EVAP purge solenoid 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 solenoid ON and EVAP purge solenoid OFF (EVAP vent solenoid CLOSED, EVAP purge PWM 0%). If the fuel tank vacuum level increases during the test, a continuous purge flow condition is indicated. This can be caused by the following conditions:
- EVAP purge solenoid leaking
- EVAP purge and engine vacuum lines switched at the EVAP purge solenoid
- EVAP purge solenoid driver circuit grounded
If any of these conditions are present, DTC P1441 will set.
Conditions for Setting the DTC
- No TP sensor, ODM, IAT sensor, or MAP sensor DTCs are set.
- Intake air temperature is above 0 °C (32 °F).
- Fuel tank level is between 15% and 85%.
- A continuous open purge flow condition is detected during the diagnostic test.
Action Taken When the DTC Sets
- The PCM will illuminate the Malfunction Indicator lamp (MIL) during the second key cycle trip in which the DTC sets.
- The PCM will store conditions which were present when the DTC was set as Freeze Frame and in the Failure Records data.
Conditions for Clearing the MIL/DTC
- The PCM will turn the MIL OFF on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A history DTC P1441 will clear after 40 consecutive warm-up cycles have occurred without a fault.
- DTC P1441 can be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:
- Poor connection at PCM. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
- Damaged harness. Inspect the wring harness for damage. If the harness appears to be OK, connect the EVAP pressure/purge cart J41413 to the EVAP service port, pressurize the EVAP system to 10 in. H2O and observe the Fuel Tank Vacuum display on the scan tool while moving connectors and wiring harnesses related to the EVAP purge solenoid. A sudden change in the display will indicate the location of the fault.
- Incorrect vacuum line routing. Verify that the source vacuum line routing to the EVAP purge solenoid is correct and that the EVAP purge and source vacuum lines to the EVAP purge solenoid are not switched.
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Steps 1 - 3:
Steps 4 - 7:
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Chart.
2. If an EVAP purge solenoid electrical fault is present, the purge system will not operate correctly. repairing the electrical fault will very likely correct the condition that set DTC P1441.
3. Checks the fuel tank vacuum sensor at ambient pressure.
4. Checks for a stuck open EVAP purge solenoid.
5. Verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes.
7. If the EVAP purge and engine vacuum lines are switched at the EVAP purge solenoid, the solenoid valve will leak vacuum.