GM Service Manual Online
For 1990-2009 cars only

Description

This diagnostic trouble code (DTC) tests for undesired intake manifold vacuum flow to the evaporative emissions (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 powertrain control module (PCM) monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. This DTC will set if the vacuum in the EVAP system is more than a predetermined value within a predetermined time.

Conditions for Running the DTC

    • DTCs P0440, P0442, P0446, P0107, P0108, P0110, P0112, P0113, P0115, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121, or P1122 are not set.
    • The system voltage is between 10-18 volts.
    • The startup engine coolant temperature (ECT) is between 4-30°C (39-86°F).
    • The startup intake air temperature (IAT) is between 4-30°C (39-86°F).
    • The fuel tank level is between 15-85 percent.
    • The barometric pressure (BARO) is more than 75 kPa.
    • The vehicle speed sensor (VSS) is less than 120 km/h (75 mph).

Conditions for Setting the DTC

The PCM detects 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

The EVAP system tests run when the engine is first started and meets the Conditions for Running the DTC. An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge valve or a temporary blockage in the EVAP canister purge valve. To repair a blockage in the EVAP system refer to EVAP 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.

DTC P1441

Step

Action

Values

Yes

No

Schematic Reference: Emission Hose Routing Diagram and Engine Controls Schematics

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. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, monitor the fuel tank pressure (FTP) sensor.

Does the scan tool indicate fuel tank pressure within the specified range?

-0.5 to +0.5 in H2O

Go to Step 5

Go to Step 4

4

  1. Disconnect the fuel tank harness inline connector.
  2. With a scan tool, monitor the FTP.

Does the scan tool indicate fuel tank pressure within the specified range?

-0.5 to +0.5 in H2O

Go to Step 6

Go to DTC P0453

5

  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 EVAP diagnostic station indicate an increase in vacuum?

--

Go to Step 7

Go to Diagnostic Aids

6

Replace the fuel tank pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 8

--

7

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

Did you complete the replacement?

--

Go to Step 8

--

8

  1. With a scan tool, review and record the Freeze Frame/Failure Records data.
  2. With a scan tool, clear the DTCs.
  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 9

Go to Step 3

9

With a scan tool, select the review Info option.

Does the scan tool indicate any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK