P0441

Circuit Description
Canister purge is controlled by a solenoid valve that 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 (purse 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 EVAP purge vacuum switch is a normally closed switch positioned in the purge line between the canister and the EVAP purge solenoid. The EVAP purge vacuum switch will open when vacuum increases to greater than 5 inches of water in the purge line. The PCM monitors the EVAP purge vacuum switch signal to determine if the evaporative emission control system is working properly. If the switch is closed (no purge flow) when the PCM is commanding the EVAP purge solenoid "ON," DTC P0441 will be set.

Conditions for Setting the DTC
- No active ECT sensor, IAT sensor, MAP sensor, TP sensor, or vacuum switch DTCs set.
- BARO reading is above 85 kPa.
- Engine coolant temperature is below 70°C(158°F).
- Start-up intake air temperature (IAT) sensor and start-up engine coolant temperature (ECT) sensor both above 5°C (41°F).
- The difference between start-up ECT and start-up IAT is less than 25°C (45°F).
- Engine speed is above 800 RPM and 6,000 RPM.
- TP sensor indicates a throttle position above 12%.
- Battery voltage is between 11.5 volts and 16 volts.
- Canister purge duty cycle is above 95%.
- Canister purge vacuum switch remains closed for 3 seconds with when the PCM is commanding the EVAP purge side solenoid "ON.

Action Taken When the DTC Sets
- The PCM will illuminate the malfunction indicator lamp (MIL) after the second consecutive trip in which the fault is detected.
- 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 P0441 will clear after 40 consecutive warm-up cycles have occurred without a fault.
- DTC P0441 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 matin9, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.
- Damaged harness - Inspect the wiring harness for damage. If the harness appears to be OK, observe the EVAP vacuum switch display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.
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.












Diagnostic Chart