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P1441

Schematic:




The Evaporative Emission (EVAP) system is used to store fuel vapors as to reduce the amount of unburned fuel from escaping into the atmosphere. The EVAP purge solenoid is used to control the flow of fuel vapors from the EVAP canister to the intake manifold. The EVAP purge solenoid is commanded On (PWM) whenever the EVAP system is in purge mode. Fuel vapors can be purged at anytime the PCM is in closed loop and the vehicle is not in a decel. The PCM controls the EVAP purge solenoid by controlling an internal driver that pulls the solenoid circuit to ground. The EVAP purge solenoid circuit is monitored for low and high voltage faults. During one part of the EVAP system test, the PCM will close the EVAP purge solenoid and EVAP vent solenoid. DTC P1441 sets when the fuel tank pressure sensor indicates that the pressure is lower than atmospheric (vacuum) indicating the EVAP purge solenoid is stuck open.

DTC PARAMETERS
DTC P1441 will set if the fuel tank pressure sensor is indicating to the PCM that 6 inches of H2O or more are being pulled on the EVAP system during the EVAP diagnostic system test when:
^ Condition exists for 4 seconds
^ Engine is running
^ EVAP vent solenoid is commanded On (closed)
^ EVAP purge solenoid is commanded Off (closed)
^ Fuel tank level is between 15 and 85% full
^ Baro is greater than 81 kPa
^ IAT at engine start-up is between 50 and 32°C (410 and 90°F)
^ ECT and IAT are within 10°C (50°F) of each other
^ Ignition voltage is between 11 and 18 volts
^ No ECT fuel tank pressure, IAT MAP or VSS DTCs have been set

DTC P1441 diagnostic runs once per ignition cycle during the EVAP diagnostic system test.

DTC P1441 is a type A DTC.

DIAGNOSTIC AIDS

IMPORTANT:
^ If DTC P0444 or P0445 is set, diagnose that DTC first. A diagnosed EVAP purge solenoid circuit fault may have caused this DTC to set.
^ The PCM uses the fuel tank pressure sensor to detect the amount of vacuum pulled on the EVAP system during the EVAP purge diagnostic. Make sure the fuel pressure sensor is not skewed by verifying FUEL TANK PRESSURE on Scan tool is between 1.3 and 1.7 volts with ignition On and fuel cap removed.

The most likely cause of DTC P1441 is a stuck open EVAP purge solenoid. Use Scan tool to command the EVAP PURGE SOLENOID On (PWM). The solenoid should click at an even rate. Replace solenoid if solenoid intermittently sticks.

EVAP purge solenoid resistance: 19 - 31 ohms