GM Service Manual Online
For 1990-2009 cars only

Circuit Description

This diagnostic trouble code (DTC) tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The control module seals the EVAP system by commanding the EVAP purge valve OFF, closed and the EVAP vent valve ON, closed. The control module 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 predetermined value within a predetermined time, DTC P1441 will set.

Conditions for Running the DTC

    • DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0440, P0442, P0443, P0446, P0449, P0452, P0453, P1111, P1112, P1114, P1115, P1120, P1220, P1221 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

The PCM detects a vacuum during a non-purge condition.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

    • The control module turns OFF the malfunction indicator lamp (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 the DTC with a scan tool.

Diagnostic Aids

An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge valve, or by a temporary blockage in the EVAP canister purge valve. In order to repair a blockage in the EVAP system, refer to Evaporative Emission System Cleaning .

Test Description

The number below refers to the step number on the diagnostic table.

  1. Because of temperature restrictions, use the Service Bay Test in order to complete the test procedure.

Step

Action

Values

Yes

No

Schematic Reference: Evaporative Emissions Hose Routing Diagram

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Are DTCs P0443, P0449, P0452, or P0453 also set?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Remove and install the fuel filler cap.
  2. Turn ON the ignition, with the engine OFF.
  3. Monitor the fuel tank pressure (FTP) sensor with a scan tool.

Does the scan tool indicate FTP within the specified range?

-0.5 to +0.5 in H2O

Go to DTC P0453

Go to Step 4

4

  1. Disconnect the purge pipe from the EVAP canister purge valve.
  2. Install a hand-held vacuum gage to the EVAP purge port.
  3. Disconnect the EVAP canister purge valve harness connector.
  4. Monitor vacuum on the vacuum gage.
  5. Start the engine and allow the engine to idle.
  6. Increase the idle to 1,200-1,500 RPM.

Does the vacuum gage indicate an increase in vacuum?

--

Go to Step 5

Go to Diagnostic Aids

5

Replace the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement .

Did you complete the replacement?

--

Go to Step 6

--

6

  1. Review and record the Freeze Frame/Failure Records data with a scan tool.
  2. Clear the DTCs with a scan tool.
  3. Perform the Service Bay Test. Refer to Service Bay Test .

Does the scan tool indicate that the Service Bay Test has passed?

--

Go to Step 7

Go to Step 3

7

Observe the stored information, Capture Info, with a scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK