Here are the explanation and diagnostic procedures.
DTC P1441: EVAPORATIVE EMISSION SYSTEM FLOW DURING NON-PURGE
DTC tests for undesired intake manifold vacuum flow to the Evaporative Emission (EVAP) system. The PCM seals the EVAP system by commanding the EVAP canister purge valve Closed and the EVAP canister vent valve Closed. The PCM monitors the Fuel Tank Pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent valves. See EVAP CANISTER PURGE VALVE/ VENT VALVE RELATIONSHIP.
Conditions For Running DTC
DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0440, P0442, P0446, P0452 or P0453 are not set.
The ignition voltage is 10-18 volts.
The BARO sensor parameter is more than 75 kPa.
The Fuel Level sensor parameter is 15-85 percent.
The ECT sensor parameter is 39-86 F (4-30 C).
The IAT sensor parameter is 39 -86 F (4-30 C).
The start-up ECT and IAT are within 16 F (9 C) of each other.
The VSS parameter is less than 75 MPH.
Conditions For Setting DTC
The PCM detects vacuum during a non-purge condition.
Actions Taken When DTC Sets
The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions For Clearing MIL/DTC
The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and DTC using a scan tool.
The number below refer to the step number on the diagnostic procedure.
2 - This step inspects for a leaking EVAP purge solenoid.
4 - Removing the fuel fill cap will equalize the pressure inside the tank with atmospheric pressure. At zero in. Of H2O the FTP sensor should be near 1.5 volts. If the sensor is not, there is a concern with the sensor or related wiring.
1. Perform diagnostic system check - engine controls. After performing diagnostic system check - engine controls, go to next step.
2. Disconnect the purge pipe from the EVAP purge solenoid. Connect a hand held vacuum gauge to the EVAP purge solenoid purge port. Disconnect the EVAP purge solenoid harness connector. Monitor vacuum on the vacuum gauge. Start the engine and allow the engine to idle. Increase the idle to 1200-1500 RPM. Does the vacuum gauge indicate an increase in vacuum? If yes, go to step 8. If no, go to next step.
3. Connect the EVAP purge solenoid harness connector. Monitor vacuum on the vacuum gauge. Increase the idle to 1200-1500 RPM. Does the vacuum gauge indicate an increase in vacuum? If yes, go to step 5. If no, go to next step.
4. Turn ignition switch to OFF position. Remove and then install the fuel fill cap. Turn ignition switch to RUN position, engine OFF. Observe the Fuel Tank Pressure (FTP) sensor parameter using a scan tool. Is the FTP sensor parameter -0.5 to 0.5 in. H2O? If yes, go to
5. Check the EVAP purge solenoid control circuit for a short to ground. Did you find and correct the conditions? If yes, go to step
11. If no, go to next step.
6. Check for an intermittent and for a poor connection at the EVAP purge solenoid. Did you find and correct the condition? If yes, go to step 11. If no, go to next step.
7. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11. If no, go to step 10.
8. Replace the FTP sensor. After repair, go to step 11.
9. Replace the EVAP purge solenoid. After repair, go to step
10. Replace PCM. Perform PCM relearn procedure. After replacing
PCM, go to next step.
11. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. Did the DTC fail this ignition? If yes, go to step 2. If no, go to next step.
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no, system is okay at this time.
An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge valve or a temporary blockage in the EVAP purge solenoid.
For intermittent conditions, refer to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
Wednesday, December 15th, 2010 AT 2:13 PM