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 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. |
Test Description
The number below refers to the step number on the diagnostic table.
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 | |
2 | Is DTC P0452 or P0453 also set? | -- | Go to Step 3 | |
3 |
Is the FTP sensor near the specified value? | 0 Hg (0 H2O) | Go to Diagnostic Aids | Go to Step 4 |
Is the FTP sensor near the specified value? | 0 Hg (0 H2O) | Go to Step 5 | Go to Step 7 | |
5 |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Diagnostic Aids |
6 | Test the purge valve control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
7 |
Important: Check for carbon release into the EVAP system. Refer to Evaporative Emission System Cleaning . Replace the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
8 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Wiper/Washer Schematics in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
9 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Is the fuel tank pressure near the specified value? | 0 Hg (0 H2O) | Go to Step 11 | Go to Step 3 |
11 | With a scan tool, observe the stored information, Capture Info. Are there any DTCs that you have not diagnosed? | -- | System OK | |
