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Greg A
Greg A, Master Troubleshooter
Category: Chevy
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Experience:  Working with Electronics & Cars for 25+ Years
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My 02 Chevy TrailBlazer had a P1441 code which OnStar said

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My 02 Chevy TrailBlazer had a P1441 code which OnStar said was an emissions thing, the light on the dash is now gone and no codes are coming up with OnStar. Is this something I need to be concerned about?

Hello & Welcome,


The OnStar folks were correct - this code is part of the emissions system, or more exactly, part of the Evaporative Emissions System. Here is the details from the maintenance manual.


DTC P1441

System Description

This DTC tests for undesired intake manifold vacuum flow to the Evaporative Emission (EVAP) system. The powertrain control module (PCM) seals the EVAP system by commanding the EVAP purge valve OFF (closed) and the EVAP vent valve ON (closed). The PCM monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If the vacuum in the EVAP system is more than a calibrated value within a calibrated time, DTC P1441 will set.

Conditions for Running the DTC

  • DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0440, P0442, P0446, P0452, or P0453 are not set.
  • The ignition voltage is between 10-18 volts.
  • The barometric pressure (BARO) is more than 75 kPa.
  • The fuel level is between 15-85 percent.
  • The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
  • The intake air temperature (IAT) is between 4-30°C (39-86°F).
  • The start up ECT and IAT are within 9°C (16°F) of each other.
  • The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

Conditions for Setting the DTC

A continuous open purge flow condition is detected during the diagnostic test (fuel tank pressure decreases to less than -11 inches H2O).

Conditions for Clearing the MIL/DTC

  • The PCM will turn the MIL OFF during the first trip in which the diagnostic has been run and passed.
  • The history DTC will clear when the PCM turns OFF the MIL.
  • The DTC can be cleared by using a scan tool.

Diagnostic Aids

  • Carbon release from the EVAP canister could cause the purge valve to stick open intermittently . To check for carbon release in the EVAP system, refer to Evaporative Emission (EVAP) System Cleaning .
  • 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.


If you have a smog test coming up soon, then this might be a concern. But if it is not causing any other performance problems, then I would not worry about it at this time, as the test was run and passed, which is what cleared the code & the light on the dash. Without that light on, and the condition present that caused to light in the first place, any tech would just be guessing at what was wrong.


I hope this helps. Please let me know if you need more information.


Take Care, Greg A.

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