P1441
CIRCUIT DESCRIPTIONThe evaporative system includes the following components:
^ The fuel tank
^ The EVAP canister vent valve
^ The fuel pipes and hoses
^ The fuel cap
^ The EVAP vapor lines
^ The EVAP purge lines
^ The evaporative emission canister
^ The EVAP purge valve
The PCM tests the EVAP system for the following conditions:
^ Large and small leaks (P0440 and P0442)
^ Excess vacuum (P0446)
^ Purge flow during non-commanded conditions (P1441)
^ Fuel pressure sensor and fuel level sensor faults (P0452, P0453, P0461, P0462, and P0463)
^ EVAP purge and vent valve solenoid malfunctions (P0443 and P0449)
At the appropriate time, the PCM seals the system by turning the EVAP purge OFF, and the canister vent valve ON (both valves closed). The PCM uses the input from the fuel tank pressure sensor to monitor the system vacuum. If the PCM detects an increase in system vacuum (continuous purge condition), the PCM will set DTC P1441. Any of the following conditions will cause DTC P1441 to set:
^ EVAP purge valve leaking or damaged
^ EVAP purge valve control circuit grounded
CONDITIONS FOR RUNNING THE DTC
^ No TP sensor, MAP sensor, VSS, IAT sensor, ECT sensor, fuel tank pressure sensor, fuel level sensor, EVAP purge control, or EVAP vent control DTCs are set.
^ System voltage is between 10 and 16 volts.
^ Barometric pressure is more than 72 kPa.
^ Fuel level is steady between 10 and 90 percent.
CONDITIONS FOR SETTING THE DTC
The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.
ACTION TAKEN WHEN THE DTC SETS
IMPORTANT: Although these diagnostics are considered type A, they act like type B diagnostics under certain conditions. Whenever the EVAP diagnostics report that the system has passed, or the code has been cleared, the diagnostic must fail during two consecutive trips before setting a DTC. The initial failure is not reported to the diagnostic manager or displayed on the scan tool.
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) after 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 Fail Records data.
CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.
DIAGNOSTIC AIDS
IMPORTANT: An accurate indication of fuel level is required for the PCM to properly RUN this diagnostic. Always diagnose fuel level sensor DTC's before performing this diagnostic table. Always check for fuel level sensor DTC's stored as History.
Perform a physical inspection of the EVAP system. Check for the following conditions:
^ A loose, missing, defective, or incorrect fuel tank cap
^ Incorrectly routed, kinked, pinched, plugged, or defective EVAP system vacuum and vapor lines
^ A malfunctioning or damaged EVAP vapor canister
Check for charcoal release from the EVAP vapor canister. Refer to EVAP System Cleaning.
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.
TEST DESCRIPTION
