System Description
The DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge diagnostic monitors the changes in the vacuum pressure in the fuel tank. The diagnostic strategy for the EVAP system uses a vacuum pump to test for system leaks, after the engine is OFF. A unique fuel tank, EVAP canister, and EVAP vacuum leak pump work together to provide enhanced system diagnosis. The vacuum leak pump, the fuel tank pressure (FTP) sensor and the EVAP canister vent valve are all integral parts of one assembly. The assembly is attached directly to the EVAP canister, located near the fuel tank.
After the vehicle has sat with the engine OFF for about 5 hours, a comprehensive diagnostic is enabled with no operator input necessary. The complete test can take up to 15 minutes to run, with leak detection comprising the largest portion of the test. If the powertrain control module (PCM) detects the vacuum level was not achieved, DTC P0441 will set. For more detailed information on the EVAP system components and diagnostic strategy, refer to Evaporative Emission Control System Description .
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge
Conditions for Running the DTC
Condition 1
| • | DTC P0011, P0012, P0100, P0101, P0102, P0103, P0110, P0112, P0113, P0115, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0220, P0222, P0223, P0300, P0301-P0304, P0335, P0340, P0341, P0351-P0354, P0385, P0450, P0451, P0452, P0453, P0500, P2102, P2103, P2111, P2112, P2118, P2119, P2120, P2121, P2122,P21223, P2125, P2127, P2128, P2135, P2138 are not set. |
| • | Atmospheric pressure is between 70-110 kPa. |
| • | Battery voltage is more than 10.5 volts. |
| • | Intake air temperature (IAT) is between 4-35°C (40-95°F). |
| • | Engine Coolant temperature (ECT) is between 4-35°C (40-95°F). |
| • | The engine has been running for greater than 5 minutes. |
| • | DTC P0441 runs continuously when the above conditions have been met. |
Condition 2
| • | DTC P0011, P0012, P0100, P0101, P0102, P0103, P0110, P0112, P0113, P0115, P0117, P0118, P0120, P0121, P0122, P0123, P0125, P0220, P0222, P0223, P0300, P0301-P0304, P0335, P0340, P0341, P0351-P0354, P0385, P0450, P0451, P0452, P0453, P0500, P2102, P2103, P2111, P2112, P2118, P2119, P2120, P2121, P2122,P21223, P2125, P2127, P2128, P2135, P2138 are not set. |
| • | Atmospheric pressure is between 70-110 kPa. |
| • | Battery voltage is more than 10.5 volts. |
| • | Condition 1 portion of the DTC P0441 diagnostic ran and passed during the last ignition cycle. |
| • | The fuel level is between 25-75 percent. |
| • | The ignition has been OFF continuously for at least 5 hours and the ECT is less than 35°C (95°F). |
| • | DTC P0441 runs once per drive cycle when the above conditions have been met. |
Conditions for Setting the DTC
Condition 1
The pressure indicated in the EVAP canister and the fuel tank does not drop when the EVAP canister purge solenoid is ON.
OR:
The pressure indicated in the EVAP canister remains very low when compared to atmospheric pressure when the EVAP canister purge solenoid is OFF.
Condition 2
The pressure indicated by the fuel tank pressure sensor during EVAP vacuum pump operation is not within the specified values.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) after 2 consecutive ignition cycles in which the diagnostic runs with the fault active. |
| • | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present. |
| • | A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault. |
| • | A DTC can be cleared by using the scan tool Clear Information function. |
Diagnostic Aids
| • | If DTC P0441 is the only EVAP DTC set, the most likely cause is a malfunctioning EVAP canister purge valve. Inspect the EVAP canister purge valve carefully for faulty connections and erratic operation. |
| • | The information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set. If the Freeze Frame data indicates the engine was not running when the diagnostic ran and failed, the fault is probably a leak in the EVAP system. |
| • | A faulty EVAP canister can cause a DTC P0441 and P0455 to set. Test the EVAP canister for internal passage leaks and restrictions. Also test the canister for the correct operation of diaphragms, check balls, and internal valves. Refer to Evaporative Emission Control System Diagnosis . |
| • | An intermittent malfunction may be caused by a fault in any of the EVAP solenoid electrical circuits. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step verifies that the DTC P0441 is captured in the Freeze Frame/Failure Record list. When multiple EVAP system DTCs are set, the DTC stored in the Freeze Frame/Failure Record is the best diagnostic starting point.
-
This step verifies the electrical operation of the EVAP canister purge solenoid.
-
This step tests the function of the EVAP canister purge solenoid.
-
This step uses the EVAP Service Bay test in order to verify the correct operation of the EVAP canister purge solenoid and the other EVAP system components. Performing the EVAP Service Bay test also tests for EVAP system leaks.
-
This step tests for a blockage or a restriction in the purge port and purge passages located in the EVAP canister assembly. If the purge passage is blocked or restricted, the EVAP system diagnostic can fail and set this DTC.
-
This step uses the EVAP Service Bay test in order to verify the correct operation of the EVAP canister purge solenoid and the EVAP vacuum leak pump assembly. Performing the EVAP Service Bay test also tests for EVAP system leaks.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Was DTC P2420 also set? | -- | Go to DTC P2420 | Go to Step 3 | |
Command the evaporative emission (EVAP) purge solenoid ON and OFF with the scan tool. Refer to Scan Tool Output Controls . Do you hear or feel a click as the EVAP purge solenoid is commanded ON and OFF? | -- | Go to Step 4 | Go to Step 8 | |
Does the vacuum gage indicate a vacuum being applied? | -- | Go to Step 15 | Go to Step 5 | |
5 | With the engine running command the purge valve ON, OPEN. Does the vacuum gage indicate a vacuum being applied? | -- | Go to Step 6 | Go to Step 14 |
6 |
Is the FTP sensor within the specified range? | 3.5-3.8 V | Go to Step 7 | Go to DTC P0451 |
Was DTC P0455 also set? | -- | Go to DTC P0455 | Go to Step 17 | |
8 |
Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 11 |
9 |
Does the test lamp illuminate when the EVAP purge solenoid is commanded ON and turn OFF when the EVAP purge solenoid is commanded OFF? | -- | Go to Step 12 | Go to Step 10 |
10 | Test the control circuit of the EVAP purge solenoid for an open, a short to voltage, or a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 13 |
11 |
Did you complete the repair? | -- | Go to Step 19 | -- |
12 | Test for an intermittent and for a poor connection at the EVAP canister purge solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 15 |
13 | Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 16 |
14 | Inspect the EVAP purge solenoid vacuum supply for a blockage or restriction. Did you find and correct the problem? | -- | Go to Step 19 | Go to Step 15 |
15 | Replace the EVAP purge solenoid. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 19 | -- |
16 | Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 19 | -- |
17 | Inspect for a blockage or a restriction in the EVAP purge line between the purge solenoid and the EVAP canister. Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 18 |
Did you find and correct a condition? | -- | Go to Step 19 | Go to Diagnostic Aids | |
Are there any EVAP DTCs set in Last Test Failed? | -- | Go to Step 20 | Go to Step 21 | |
20 | The EVAP System failed the Service Bay Test. Is there an EVAP system DTC other than DTC P0441 that you have not diagnosed? | -- | Go to Step 3 | |
21 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
