GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2002 🢒 Firebird 🢒 Engine 🢒 Engine Controls - 5.7L 🢒 DTC P1441

Circuit 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, and the EVAP vent valve ON. The PCM monitors the fuel tank pressure (FTP) sensor in order 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, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0442, P0443, P0446, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121, and P1122 are not set.
    • The system voltage is between 10-18 volts.
    • The startup ECT is between 4-30°C (39-86°F).
    • The startup IAT is between 4-30°C (39-86°F).
    • The fuel tank level is between 15-85 percent.
    • The start up ECT and IAT are within 9°C (16°F) of each other.
    • 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

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 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 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. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, monitor the FTP sensor.

Does the scan tool indicate FTP within the specified range?

-0.5 to +0.5 in H2O

Go to Step 5

Go to Step 4

4
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Disconnect the FTP sensor harness connector. Refer to Fuel Tank Pressure Sensor Replacement .
  3. With a scan tool, monitor the FTP.

Does the scan tool indicate FTP within the specified range?

0 V

Go to Step 6

Go to DTC P0453

5
  1. Disconnect the EVAP 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 1200-1500 RPM.

Does the vacuum gage indicate an increase in vacuum?

--

Go to Step 7

Go to Diagnostic Aids

6
  1. Lower the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Inspect the fuel tank wiring harness for the following:
    3. • Damaged Wiring
    • Poor connections
    • Broken wires inside the insulation
    • Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and repair the condition?

--

Go to Step 9

Go to Step 7

7

Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 9

--

8

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

Did you complete the replacement?

--

Go to Step 9

--

9

  1. With a scan tool, review and record the Freeze Frame/Failure Records .
  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 10

Go to Step 3

10

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

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

--

Go to Diagnostic Trouble Code (DTC) List

System OK