GM Service Manual Online
For 1990-2009 cars only
Table 1: DTC P1441

System Description

This 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 canister purge valve Closed and the EVAP canister vent valve Closed. The control module 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.

Control Module Command

EVAP Canister Purge Valve

EVAP Canister Vent Valve

ON

Open

Closed

OFF

Closed

Open

Conditions for Running the DTC

    • DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0442, P0446, P0443, P0449, P0452, P0453, P1106. P1107, P1111, P1112, P1114, P1115, P1121, or P1122 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).
    • The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

Conditions for Setting the DTC

The control module detects vacuum during a non-purge condition.

Action Taken When the DTC Sets

    • The control module will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
    • The control module will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

Conditions for Clearing the MIL/DTC

    • The control module will turn OFF the MIL during the third consecutive trip in which the diagnostic ran and passed.
    • The History DTC will clear after 40 consecutive warm-up cycles without a malfunction.
    • The DTC can be cleared 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.

DTC P1441

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 the fuel fill cap.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, monitor the FTP.

Does the scan tool indicate FTP within the specified range?

-0.5 to +0.5 in H2O

Go to Step 4

Go to DTC P0453

4

  1. Disconnect the purge pipe from the EVAP canister purge valve.
  2. Install a hand held vacuum gage to the EVAP canister purge valve 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. With a scan tool, monitor the fuel tank pressure.
  2. Start the engine and allow the engine to idle for 30 seconds.

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

-0.5 to +0.5 in H2O

Go to Step 7

Go to Step 3

7

With a scan tool, observe the stored information, Capture Info. .

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

--

Go to Diagnostic Trouble Code (DTC) List

System OK