P0441

DTC P0441 EVAP System No Flow During Purge (1 Of 2):

DTC P0441 EVAP System No Flow During Purge (2 Of 2):

EVAP System:

CIRCUIT DESCRIPTION
Canister purge is controlled by a solenoid valve that allows ported vacuum to purge the canister when energized. The Vehicle Control Module (VCM) supplies a ground to energize the solenoid valve (purge ON). The purge solenoid control by the VCM is Pulse Width Modulated (PWM) or turned ON and OFF several times a second. The duty cycle (pulse width) is determined by Closed Loop feed back from the Heated Oxygen Sensor (HO2S). The duty cycle is calculated by the VCM and the output is commanded when certain conditions have been met.

A vacuum switch in the purge line is used to detect when the system is being purged. The normally closed switch will open when less than 1 in. Hg is present in the purge line. The VCM supplies a 12 V reference to the switch to ensure the Evaporative Emission (EVAP) control system is working properly. If the switch is closed (no EVAP vacuum) when the VCM is commanding purge, a DTC will be set. DTC P0441 is a type B DTC.

CONDITIONS FOR SETTING THE DTC

^ Purge solenoid diagnostic vacuum switch DTC not set.
^ No Idle Air Control (IAC) DTCs.
^ No Manifold Absolute Pressure (MAP) DTCs.
^ No Throttle Position (TP) sensor DTCs.
^ No EGR DTCs.
^ BARO greater than 75 kPa.
^ ECT less than 110°C.
^ Powerup Intake Air Temperature (IAT) greater than -18°C.
^ IAT less than or equal to 90°C.
^ The change in ECT/IAT less than or equal to 90°C.
^ Purge DC greater than or equal to 90%.
^ MAP greater than or equal to 20 kPa but less than or equal to 80 kPa.
^ Throttle position greater than or equal to 5% but less than or equal to 60%.
^ Engine speed greater than or equal to 800 RPM but less than or equal to 3000 RPM.

ACTION TAKEN WHEN THE DTC SETS
The VCM will turn ON the Malfunction Indicator Lamp (MIL) after two consecutive test cycles with the fault active.

CONDITIONS FOR CLEARING THE MIL/DTC
The VCM turns the MIL off after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

DIAGNOSTIC AIDS
Make a visual check of vacuum hose(s). Check throttle body for possible cracked, broken, or plugged vacuum block. Check engine for possible mechanical problem.

TEST DESCRIPTION
Number(s) below refer to the step numbers on the Diagnostic Table.

2. The solenoid valve will click when commanded ON and OFF by the scan tool. This determines if the VCM can control the solenoid valve.
3. Ported (off idle) vacuum is used at the solenoid valve. Vacuum will only be seen off idle with a vacuum gauge.
4. Disconnecting the vacuum switch electrical connector opens the 5 V reference circuit from the VCM which indicates that purge is present. Leaving the switch disconnected will cause a DTC P1441.
5. If voltage is not available to the solenoid valve, the VCM will not be able to command the solenoid valve ON or OFF.
6. Determines if the solenoid valve couldn't be commanded due to an electrical circuit problem or faulty solenoid.