For 1990-2009 cars
Engine Controls Components
MAF Sensor, EVAP System, EGR Valve
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The EVAP purge solenoid valve allows manifold vacuum to purge the canister. The Powertrain Control Module (PCM) supplies a ground to energize the EVAP purge solenoid valve (purge ON). The EVAP purge solenoid control is Pulse Width Modulated (PWM) or turned ON and OFF several times a second. The duty cycle (pulse width) is determined by engine operating conditions including load, throttle position, coolant temperature and ambient temperature. The duty cycle is calculated by the PCM and the output is commanded when the appropriate conditions have been met:

• | Engine coolant temperature above 25°C (77°F).

• | After the engine has been running about 2 1/2 minutes on a cold start or 30 seconds on a warm start.

• | The vehicle is operating in closed loop fuel control.

Canister purge commanded duty cycle varies according to operating conditions determined by mass air flow, fuel trim, and. intake air temperature. Canister purge will be disabled if TP angle increases to above 70%. Canister purge will be re-enabled when TP angle decreases below 66%.

The EVAP purge vacuum switch is a normally closed switch positioned in the purge line between the canister and the EVAP purge solenoid. The EVAP purge vacuum switch will open when vacuum increases to greater than 5 inches of water in the purge line. The PCM monitors the EVAP purge vacuum switch signal to determine of the evaporative emission control system is working properly. If the switch is closed (no purge flow) when the PCM is commanding the EVAP purge solenoid ON, DTC P0441 will be set.

### Conditions for Setting the DTC

• | No EVAP Vacuum Switch, TP sensor, IAT sensor, Idle Speed, MAP sensor, or EGR DTCs set.

• | BARO reading is greater than 70 kPa.

• | Engine Coolant Temperature is less than 114°C (237°F).

• | Intake Air Temperature (IAT) sensor indicates an ambient temperature less than 70°C (158°F).

• | The difference between ECT and IAT is less than 10°C (18°F).

• | Engine speed is between 550 rpm and 5000 rpm.

• | TP Sensor Indicates throttle position between 2.5% and 52%.

• | Manifold vacuum is greater than 10 kPa.

• | Canister purge PWM is greater than 75%.

• | EVAP vacuum switch remains closed (12 volts signal at the PCM).

• | Above conditions for longer than 4 seconds.

### Action Taken When the DTC Sets

• | The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.

• | The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.

• | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.

### Diagnostic Aids

Check for the following conditions:

• | Poor connection at the PCM - Inspect harness connectors for the following conditions:

- | Backed out terminals.

- | Improper mating.

- | Broken locks.

- | Improperly formed or damaged terminals.

- | Poor terminal to wire connection.

• | Damaged harness

| Inspect the wiring harness for damage

• | If the harness appears to be OK, observe the EVAP vacuum switch display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.

• | Faulty or damaged canister

| A faulty canister may intermittenly allow charcoal into the EVAP purge solenoid, vacuum switch, and associated lines causing a DTC to be set. Use the following procedure to check for a carbon release condition:

1. | Turn OFF the ignition switch.

2. | Remove the EVAP purge solenoid. Refer to Evaporative Emission Canister Purge Solenoid .

3. | Remove the EVAP vacuum switch. Refer to Evaporative Emission Vacuum Switch .

4. | Lightly tap the purge solenoid and (if applicable) the vacuum switch on a clean work area looking for carbon particles exiting either of the vacuum ports.

5. | If no carbon release is evident, reinstall the components and continue with the DTC P0441 diagnostic table. If carbon is being released from either component, continue with this service procedure.

6. | Remove the EVAP Canister from the vehicle. Refer to Evaporative Emission Canister Replacement

7. | Ensure that the main cylinder valve is turned off on the

(1) | Main Valve
(2) | Evaporative Emission System Purge/Presure Diagnostic Station J 41413
(3) | Nitrogen Cylinder
(4) | Black Connecting Hose
(5) | Threaded Fitting
(6) | Gauge Set

EVAP purge/pressure diagnostic station.

8. | Disconnect the black hose that connects the nitrogen cylinder to the EVAP purge/pressure diagnostic station at the pressure regulator by unscrewing the knurled nut on the regulator. No tools are required to remove the black hose from the regulator.

9. | Using a section of vacuum line, connect one end over the open threaded fitting of the EVAP purge/pressure diagnostic station pressure regulator.

10. | Connect the remaining end to the purge solenoid end of the EVAP purge line at the vehicle and turn on the main nitrogen cylinder valve. Continue to blow any debris from the purge line for 15 seconds.

11. | Return the EVAP Pressure/Purge Diagnostic Station to its original condition by re-installing the black hose that was disconnected in step 8.

12. | Replace the following components:

• | Replace the EVAP purge solenoid. Refer to Evaporative Emission Canister Purge Solenoid .

• | Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement .

• | Replace the EVAP vacuum switch. Refer to Evaporative Emission Vacuum Switch .

13. | Proceed with the DTC P0441 diagnostic table.

Review the Fail Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

### Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to the Powertrain On Board Diagnostic (OBD) System Check
2 |

1. Select output controls, EVAP purge solenoid on the scan tool.
2. With the engine idling, observe EVAP Vacuum Sw.on the scan tool.
3. Command the EVAP purge solenoid ON with the scan tool.

Does the EVAP Vacuum Sw. display Purge with the EVAP purge solenoid commanded ON?

--

Go to Step 3

Go to Step 4

3 |

1. Review and record scan tool Fail Records data.
2. Operate the vehicle within Fail Records conditions.
3. Using a scan tool, monitor Specific DTC info for DTC P0441 until the DTC P0441 test runs.

Does the scan tool indicate DTC P0441 failed this ignition?

--

Go to Step 4

Refer to Diagnostic Aids

4 |

1. Disconnect the purge line to the canister at the evap vacuum switch.
2. Plug the purge line fitting at the evap vacuum switch.
3. With the engine idling, observe EVAP Vacuum Sw. on the scan tool.
4. Command the EVAP purge solenoid ON with the scan tool.

Does the scan tool display Purge?

--

Go to Step 5

Go to Step 6

5 | Check the purge line to canister for damage or improper connections. Was a problem found? | -- | Go to Step 20 | Go to Step 14
6 |

1. Turn OFF the ignition switch.
2. Install a vacuum gauge between the EVAP purge solenoid and the Vacuum Switch.
3. With the engine idling, command the EVAP purge solenoid ON with the scan tool.

Does the vacuum gauge indicate vacuum greater than the specified value?

12 in. Hg

Go to Step 7

Go to Step 8

7 |

1. Turn OFF the ignition switch.
2. Disconnect the EVAP vacuum switch electrical connector.
3. Turn ON the ignition switch.
4. Observe EVAP Vacuum Sw. on the scan tool.

Does the scan tool display Purge?

--

Go to Step 15

Go to Step 9

8 |

1. Turn OFF the ignition switch.
2. Install the vacuum gauge in the source line to the EVAP purge solenoid.
3. Engine idling, observe the vacuum gauge.

Does the gauge indicate vacuum greater than the specified value?

12 in. Hg

Go to Step 10

Go to Step 16

9 |

1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Turn ON the ignition switch.
4. Check for a short to voltage in the EVAP vacuum switch input circuit.
5. If a problem is found, repair as necessary. Refer to Wiring Repairs in Electrical Diagnosis.

Was a problem found?

--

Go to Step 20

Go to Step 19

10 |

1. Turn OFF the ignition switch.
2. Disconnect EVAP purge solenoid electrical connector.
3. Connect a J 35616-200 Unpowered Test Light between the EVAP purge solenoid connector terminals.
4. Turn ON the ignition switch.
5. Using the scan tool, command the EVAP purge solenoid ON.

Is the test light ON?

--

Go to Step 17

Go to Step 11

11 |

1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Connect a test light between the EVAP purge solenoid connector terminals.
4. Turn ON the ignition switch.
5. Jumper the EVAP purge solenoid driver circuit to ground at the PCM connector.

Is the test light ON?

--

Go to Step 12

Go to Step 13

12 | Check for a poor connection at the PCM. Was a problem found? | -- | Go to Step 20 | Go to Step 19
13 |

1. Locate the EVAP purge solenoid wiring problem. Check for the following conditions:

• | EVAP purge solenoid ignition feed circuit open or shorted to ground.

• | EVAP purge solenoid driver circuit open.

2. Repair faulty circuit as necessary. Refer to Wiring Repair in Electrical Diagnosis.

Is the action complete?

--

Go to Step 20

--

14 | Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement . Is the action complete? | -- | Go to Step 20 | --
15 | Replace the EVAP vacuum switch. Refer to Evaporative Emission Vacuum Switch Is the action complete? | -- | Go to Step 20 | --
16 | Locate and repair the cause of no vacuum. Is the action complete? | -- | Go to Step 20 | --
17 |

1. Check for a poor connection at the EVAP purge solenoid.
2. If a problem is found, repair as necessary. Refer to Wiring Repair in Electrical Diagnosis.

Was a problem found?

--

Go to Step 20

Go to Step 18

18 | Replace the EVAP purge solenoid. Refer to Evaporative Emission Canister Purge Solenoid Is the action complete? | -- | Go to Step 20 | --
19 | Replace the PCM. Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | Go to Step 20 | --
20 |

1. Review and record scan tool Fail Records data.
2. Clear DTCs.
3. Operate the vehicle within Fail Records conditions as noted.
4. Using a scan tool, monitor Specific DTC info for DTC P0441 until the DTC P0441 test runs.

Does the scan tool indicate DTC P0441 failed this ignition?

--

Go to Step 2

System OK