For 1990-2009 cars

### Circuit Description

The DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge diagnostic monitors the purge operation of the EVAP system. The powertrain control module (PCM) monitors the positive or negative pressure in the fuel tank using the fuel tank pressure (FTP) sensor. Under certain engine operating conditions, the PCM turns ON the evaporative emission (EVAP) pressure switching solenoid in order to control the pressure in the EVAP system. The PCM is able to detect any abnormal conditions by the fluctuation of this pressure. The diagnostics performed by the fuel tank pressure sensor can warn the driver of a malfunction in the EVAP system by illuminating the malfunction indicator lamp (MIL). The EVAP control system prevents the emission of the fuel vapors. The fuel vapor generated in the fuel tank while driving or idling enters the EVAP canister where a charcoal element absorbs and stores the fuel vapor. The EVAP canister is purged by the PCM controlled EVAP canister purge valve. The EVAP canister purge valve releases the fuel vapors into the intake manifold to be burned in the combustion process.

### Conditions for Running the DTC

• | The barometric pressure (BARO) is more than 75 kPa.

• | The fuel level is between ¼ and ¾.

• | The engine coolant temperature (ECT) sensor is between 10-35°C (50-95°F) at engine start.

• | The ECT sensor and the intake air temperature (IAT) sensor are near the same temperature at engine start.

• | The ECT sensor is at least 70°C (158°F) after engine warm up.

### Conditions for Setting the DTC

The pressure indicated in the EVAP canister and the fuel tank does not drop when the EVAP canister purge valve is ON.

### 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 an inoperable EVAP canister purge valve. Inspect the EVAP canister purge valve carefully for faulty connections and erratic operation.

• | An intermittent DTC P0441 can be caused by a faulty EVAP canister. An EVAP canister that has released carbon particles can cause the EVAP canister purge valve to fail and leak intermittently. Inspect the EVAP purge system for carbon contamination before returning the vehicle to service. Refer to Evaporative Emission System Cleaning .

• | A DTC P0441 is more likely to set during city driving. Avoid operating the vehicle on the highway when validating DTC P0441.

• | If a DTC P0441 is intermittent, driving the vehicle under the conditions outlined in the Inspection/Maintenance (I/M) section can verify whether the fault is present. Refer to Inspection/Maintenance Evaporative Emission System Set .

• | For functional checks of the components listed above, 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 .

If the DTC cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. The Diagnostic System Check-Engine Controls prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. This step checks the EVAP control system components for correct installation or damage. Inspect all lines and hoses. This includes a manufacturer approved gas cap that is correctly installed and tightened.

3. This step determines if a FTP sensor malfunction is present. The input signal of the FTP sensor should indicate atmospheric pressure with the fuel tank filler cap removed. The FTP sensor will vary with atmospheric pressure. A typical pressure at sea level is between 0.0-0.99 mm Hg (0.0-0.5 in H2O).

4. This step checks for the correct function of the EVAP canister purge valve.

5. This step checks the control circuit of the EVAP canister purge valve. Because the control circuit of the EVAP canister purge valve is pulse width modulated (PWM), the test lamp flickers during illumination, when commanded ON by the scan tool. This is the normal condition, indicating that the PCM and control circuit are OK.

6. This step checks for a possible leak in the EVAP system. The purpose of this inspection is to determine whether 5-6 inches of H2O can be obtained and held for at least 2 minutes.

7. This step checks for leaks in the EVAP system. By plugging the ORVR vent line, and connecting the EVAP vapor line to the purge line, the EVAP system can be pressurized and checked for leaks. Be sure to check all connections and sealing points for leaks.

8. This step checks whether there is trapped negative or positive pressure at the FTP sensor.

9. The EVAP canister has component parts that cannot be diagnosed or tested on the vehicle. The EVAP canister should be inspected off the vehicle and tested for correct operation by performing the EVAP canister inspection procedures in EVAP Control System Diagnosis.

10. This step determines if the malfunction that caused the DTC P0441 is still present. Operating the vehicle in Check mode enhances the diagnostic capabilities of the PCM. The EVAP purge diagnostic can be monitored on the scan tool under the I/M System Information. When the EVAP test displays a YES status, indicating that the purge system diagnostic is completed, check for DTC P0441 in the Last Test Failed screen of the scan tool. If there is no DTC P0441 displayed the EVAP system diagnostic has run and passed, indicating that no malfunction was present this time. The DTCs MUST be cleared in order to view the Current Status of the system diagnostics being performed. Do not forget that the I/M System Information tests only indicate that the test has run, not whether the test passed or failed. The Last Test Failed screen must be checked for related DTCs in order to determine the outcome of the diagnostic test involved.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: 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 | Install a scan tool and check for DTCs. Is a DTC P0450 or P0451 present? | -- | Go to DTC P0450 or DTC P0451 | Go to Step 3
3 |

1. Visually and physically inspect the EVAP control system for the correct installation and routing of the lines and hoses. Refer to the Evaporative Emission Control System Description for EVAP system hose routing diagrams.
2. Visually and physically inspect all of the following components for cracks, leaks, or damage:

• | The EVAP canister purge valve

• | The fuel tank pressure (FTP) sensor

• | The EVAP pressure switching solenoid

• | The EVAP canister

• | The EVAP system lines, hoses, and fittings

• | The fuel tank

3. Inspect the fuel tank filler cap for the correct part and the correct installation.
4. Repair any faults found as necessary.

Was repair necessary?

--

Go to Step 44

Go to Step 4

4 |

1. Loosen the fuel tank filler cap in order to release any pressure inside the fuel tank.
2. Turn ON the ignition, with the engine OFF.
3. Observe the FTP sensor parameter on the scan tool.

Is the FTP sensor within the specified range?

0.0-0.99 mm Hg (0.0-0.5 in H2O)

Go to Step 5

Go to Step 22

5 |

1. Disconnect both vacuum hoses from the EVAP canister purge valve.
2. Blow air into the lower port of the EVAP canister purge valve. Air should NOT pass through the solenoid and out the upper port.
3. Turn ON the ignition, with the engine OFF.
4. Using a scan tool command the EVAP canister purge valve ON.
5. Blow air into the lower port of the EVAP canister purge valve. Air should pass through the solenoid and out of the upper port.

Did the EVAP canister purge valve pass both tests?

--

Go to Step 9

Go to Step 6

6 | Measure the resistance of the EVAP canister purge valve with a DMM. Is the resistance less than the specified range? | 27-33 ohms at 20°C (68°F) | Go to Step 40 | Go to Step 7
7 |

1. Disconnect the electrical connector from the EVAP canister purge valve.
2. Turn ON the ignition, with the engine OFF.
3. Probe the harness side of the ignition positive voltage circuit of the EVAP canister purge valve with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 17

8 |

1. Turn ON the ignition, with the engine OFF.
2. Probe the engine harness side of the control circuit of the EVAP canister purge valve with a test lamp connected to B+.
3. Use the scan tool in order to command the EVAP canister purge valve ON and OFF while observing the test lamp.

Did the test lamp illuminate only when the EVAP canister purge valve was commanded ON?

--

Go to Step 37

Go to Step 36

9 |

1. Disconnect the vacuum hose from the EVAP canister vent valve.
2. Blow air into the lower port of the EVAP canister vent valve. Air should pass through the solenoid and out the upper port.
3. Turn ON the ignition, with the engine OFF.
4. Using a scan tool, command the EVAP canister vent valve ON.
5. Blow air into the lower port of the EVAP canister vent valve. Air should NOT pass through the solenoid and out of the upper port.

Did the EVAP canister vent valve pass both tests?

--

Go to Step 13

Go to Step 10

10 | Measure the resistance of the EVAP canister vent valve with a DMM. Is the resistance less than the specified range? | 25-30 ohms at 20°C (68°F) | Go to Step 38 | Go to Step 11
11 |

1. Disconnect the electrical connector from the EVAP canister vent valve.
2. Turn ON the ignition, with the engine OFF.
3. Probe the harness side of the ignition positive voltage circuit of the EVAP canister vent valve with a test lamp connected to ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 17

12 |

1. Turn ON the ignition, with the engine OFF.
2. Probe the engine harness side of the control circuit of the EVAP canister vent valve with a test lamp connected to B+.
3. Command the vent valve ON and OFF with the scan tool.

Did the test lamp illuminate only when the vent valve solenoid was commanded ON?

--

Go to Step 39

Go to Step 36

13 |

1. Disconnect both vacuum hoses from the EVAP pressure switching solenoid.
2. Blow air into the port closest to the solenoid body. Air should not pass through the port farthest from the solenoid body.
3. Turn ON the ignition, with the engine OFF.
4. Command the pressure switching solenoid ON with the scan tool.
5. Blow air into the port closest to the solenoid body. Air should pass through the port farthest from the solenoid body.

Did the pressure switching solenoid pass both tests?

--

Go to Step 18

Go to Step 14

14 | Measure the resistance of the EVAP pressure switching solenoid with a DMM. Is the resistance less than the specified range? | 37-44 ohms at 20°C (68°F) | Go to Step 32 | Go to Step 15
15 |

1. Disconnect the electrical connector from the EVAP pressure switching solenoid.
2. Turn ON the ignition, with the engine OFF.
3. Probe terminal 2 of the electrical connector on the harness side with a test lamp connected to ground.

Does the test lamp illuminate?

--

Go to Step 16

Go to Step 17

16 |

1. Turn ON the ignition, with the engine OFF.
2. Probe the engine harness side of the control circuit of the EVAP pressure switching solenoid with a test lamp connected to B+.
3. Command the solenoid ON and OFF with the scan tool.

Does the test lamp illuminate only when the valve is commanded ON?

--

Go to Step 34

Go to Step 36

17 | Repair the open in the ignition positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 44 | --
18 |

1. Remove the fuel filler cap and install the J 41415-30 Gas Cap Adapter to the fuel filler pipe.
2. Connect the J 41413 EVAP Pressure/Purge Diagnostic Station cart to the gas cap adapter.
3. Pressurize the EVAP system to the specified value with the EVAP pressure/purge cart and switch to HOLD.

Does the EVAP system hold the specified pressure for at least 2 minutes?

8.5-10.5 mm Hg (4.5-5.5 in H2O)

Go to Step 20

Go to Step 19

19 |

1. Check for a leak in the following components:

• | The EVAP pressure switching solenoid

• | The vacuum hoses connected to the EVAP pressure switching solenoid

2. Repair or replace any components as necessary.

Was a repair necessary?

--

Go to Step 44

Go to Step 21

20 | Refer to Evaporative Emission Control System Description for the EVAP system hose routing diagram used in the following procedure.

1. Remove the ORVR vent line from the EVAP canister and plug the hose. Refer to Evaporative Emission Canister Replacement .
2. Remove the EVAP vapor line and the purge line to the canister purge solenoid from the EVAP canister.
3. Connect the EVAP vapor line and the purge line together using a section of vacuum pipe.
4. Attempt to pressurize the EVAP system to the specified value with the J 41413 and HOLD.
5. Locate any leaks in the EVAP and fuel supply systems using the J 41416 Ultrasonic Leak Detector. If necessary lower the fuel tank in order to check the condition of the fill limiter vent valve and the rollover valve. Be sure to check the fuel sender assembly for a correct seal.

Were any EVAP or fuel supply system leaks found?

29 mm Hg (15 in H2O)

Go to Step 31

Go to Step 41

21 | Refer to the Evaporative Emission Control System Description for the EVAP system hose routing diagram used in the following procedure.

1. Remove the ORVR vent line from the EVAP canister and plug the hose.
2. Remove the EVAP vapor line from the EVAP canister and plug the hose.
3. Attempt to pressurize the EVAP system to the specified value with the J 41413 and HOLD.
4. Locate any leaks in the EVAP and fuel supply systems using the J 41416 . If necessary lower the fuel tank in order to check the condition of the fill limiter vent valve and the rollover valve. Be sure to check the fuel sender assembly for a correct seal.

Were any EVAP system or fuel supply system leaks found?

29 mm Hg (15 in H2O)

Go to Step 31

Go to Step 30

22 |

1. Disconnect the vapor pressure supply hose to the FTP sensor.
2. Turn ON the ignition, with the engine OFF.
3. Observe the FTP sensor parameter on the scan tool.

Is the FTP sensor within the specified range?

0.0-0.99 mm Hg (0.0-0.5 in H2O)

Go to Step 23

Go to Step 24

23 |

1. Inspect for the cause of the trapped vapor pressure to the FTP sensor. Check for the following conditions:

• | A pinched, crushed, or restricted vapor line or hose from the fuel tank

• | A blocked or restricted vapor pressure passage in the fuel tank

2. Repair as necessary.

Is the action complete?

--

Go to Step 44

--

24 |

1. Turn OFF the ignition.
2. Disconnect the electrical connector from the FTP sensor.
3. Turn ON the ignition, with the engine OFF.
4. Measure the voltage from the connector cavity 3 on the harness side using a DMM.

Does the voltage equal the specified value?

5.0 V

Go to Step 25

Go to Step 26

25 | Measure the voltage on the harness side of the connector cavity 2 with a DMM. Is the voltage near the specified value? | 4.9 V | Go to Step 28 | Go to Step 27
26 | Repair the open in the reference voltage circuit of the FTP sensor between the sensor and SP259. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 44 | --
27 |

1. Check the input circuit of the FTP sensor for an open or short.
2. Verify that the input circuit is not shorted to the sensor ground circuit.
3. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 44

Go to Step 43

28 | Probe the FTP sensor connector cavity 1 on the harness side with a test lamp connected to B+. Does the test lamp illuminate? | -- | Go to Step 35 | Go to Step 29
29 | Repair the open in the ground circuit of the FTP sensor between the sensor and S206. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 44 | --
30 | Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement . Is the action complete? | -- | Go to Step 44 | --
31 | Repair or replace the leaking EVAP system or fuel tank component. Is the action complete? | -- | Go to Step 44 | --
32 | Measure the resistance of the EVAP pressure switching solenoid with a DMM. Is the resistance less than the specified value? | 27 ohms at 20°C (68°F) | Go to Step 33 | Go to Step 34
33 | Replace the EVAP pressure switching solenoid and the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 44 | --
34 | Replace the EVAP pressure switching solenoid. Refer to Evaporative Emission Pressure Switching Solenoid Replacement . Is the action complete? | -- | Go to Step 44 | --
35 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Is the action complete? | -- | Go to Step 44 | --
36 |

1. Check the solenoid control circuit for an open or short.
2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 44

Go to Step 43

37 | Notice: The EVAP canister may have released carbon particles which caused this part to fail and may cause damage to other components. Check the EVAP canister for loose carbon before returning the vehicle to service. Replace the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement .

Is the action complete?

--

Go to Step 44

--

38 | Replace the EVAP canister vent valve and the PCM. Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement and Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 44 | --
39 | Replace the EVAP canister vent valve . Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement . Is the action complete? | -- | Go to Step 44 | --
40 | Replace the EVAP canister purge valve and the PCM. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement and Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 44 | --
41 |

1. Perform the scan tool Clear DTC Information function.
2. Place the vehicle into Check Mode using the scan tool. Refer to Service Bay Test .
3. Operate the vehicle within the Freeze Frame conditions as specified or until the EVAP purge test is complete.

Did a DTC P0441 set?

--

Go to Step 42

Go to Diagnostic Aids

42 |

1. Remove the EVAP canister. Refer to Evaporative Emission Canister Replacement .
2. Visually and physically inspect the EVAP canister for cracks or signs of damage.
3. Perform a comprehensive inspection of the EVAP canister. Refer to Evaporative Emission Control System Diagnosis .
4. Replace the EVAP canister if the canister is damaged or fails any inspections.

Was the EVAP canister replaced?

--

Go to Step 44

Go to Step 43

43 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | Go to Step 44 | --
44 |

1. Use the scan tool in order to clear the DTCs.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC or until the EVAP purge test is complete. Review the supporting text and the Test Description.

Does the DTC run and pass?

--

Go to Step 45

Go to Step 2

45 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List | System OK