For 1990-2009 cars

### Description

The EVAP large leak test applies vacuum to the evaporative emission (EVAP) system and monitors vacuum decay. The powertrain control module (PCM) monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the PCM turns the EVAP canister purge valve ON (open) and the EVAP vent valve ON (closed). This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the PCM turns the purge valve OFF (closed), sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, DTC P0440 will set.

### Conditions for Running the DTC

• | DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0452, or P0453 are not set.

• | The ignition voltage is between 10 and 18 volts.

• | The barometric pressure is more than 75 kPa.

• | The fuel level is between 15 and 85 percent.

• | The engine coolant temperature (ECT) is between 4°C and 30°C (39°F and 86°F).

• | The intake air temperature (IAT) is between 4°C and 30°C (39°F and 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

The EVAP System is not able to achieve or maintain vacuum during the diagnostic test.

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.

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

### Conditions for Clearing the MIL/DTC

• | The PCM will turn the malfunction indicator lamp (MIL) OFF during the first consecutive trip in which the diagnostic has been run and passed.

• | A last test failed (current DTC) clears when the PCM turns OFF the MIL.

• | The history DTC will clear after the PCM runs and passes 40 consecutive warm up cycles with no failure.

• | The DTC can be cleared by using a scan tool.

### Diagnostic Aids

• | 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.

• | Use the EVAP pressure/purge diagnostic station in order to pressurize the EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with the Ultrasonic Leak Detector.

• | A temporary blockage in the EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition. To repair a blockage in the EVAP system refer to Fuel System Cleaning .

### Test Description

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

1. This test verifies that the EVAP purge valve is electrically functional.

2. This test verifies that the EVAP vent valve is electrically functional.

3. This test verifies that engine vacuum is present when the EVAP purge valve is open.

4. This test verifies that the FTP sensor is accurate. An EVAP FTP sensor that does not correctly respond to vacuum (or pressure) may cause this DTC to set.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Emission 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 P0446, P0452, P0453, or P1441 also set? | -- | Go to Diagnostic Trouble Code (DTC) List | Go to Step 3
3 | Inspect the EVAP system for the following conditions:

• | A loose, incorrect, faulty or missing fuel tank fill cap

• | Damaged or disconnected EVAP system purge lines

• | A damaged EVAP system component

• | A loose, missing or damaged service port dust cap and/or schrader valve

Did you find and correct the condition?

--

Go to Step 31

Go to Step 4

4 |

1. Use the scan tool in order to clear the DTCs.
2. Command the EVAP canister purge valve to 50% and back to 0% with the scan tool.

Do you hear or feel a clicking from the EVAP purge valve when it is commanded to 50%?

--

Go to Step 5

Go to Step 6

5 | With the scan tool, command the EVAP canister vent valve ON and OFF. Do you hear or feel a click as the EVAP vent valve is commanded ON and OFF? | -- | Go to Step 10 | Go to Step 8
6 |

1. Disconnect the EVAP purge valve harness connector.
2. Turn ON the ignition, with engine OFF.
3. Connect a test lamp between the ignition voltage circuit of the EVAP purge valve and a known good ground.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 22

7 |

1. Connect a test lamp between the ignition voltage circuit and the control circuit of the EVAP purge valve.
2. With a scan tool, command the EVAP purge valve to 50% and then to 0%.

Does the test lamp illuminate when the EVAP purge valve is commanded to 50% and turn OFF when the EVAP purge valve is commanded to 0%?

--

Go to Step 18

Go to Step 16

8 |

1. Turn ON the ignition, with the engine OFF.
2. Disconnect the EVAP vent valve harness connector.
3. Connect a test lamp between the EVAP vent valve ignition voltage circuit and a good ground.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 23

9 |

1. Connect the test lamp between the ignition voltage circuit and the control circuit of the EVAP vent valve.
2. With a scan tool, command the EVAP vent valve ON.

Does the test lamp illuminate when the EVAP vent valve is commanded ON?

--

Go to Step 19

Go to Step 17

10 |

1. Turn OFF the ignition.
2. Disconnect the EVAP purge pipe from the EVAP purge valve.
3. Connect a vacuum gauge directly to the EVAP purge connection of the EVAP purge valve.
4. Start the engine.
5. Increase the engine speed to 1,500 RPM.
6. Command the EVAP canister purge valve to 50 percent with a scan tool.

Is the vacuum at or more than the specified value?

15 in H2O

Go to Step 11

Go to Step 21

11 | Important: The following steps require the J 41413 EVAP Pressure/Purge Diagnostic Station, and the J 41415-40 Fuel Tank Cap Adaptor. Always zero the EVAP pressure and vacuum (in H2O) gauges on the EVAP pressure/purge diagnostic station before proceeding with the diagnosis.

1. Reconnect the EVAP purge pipe to the EVAP canister purge valve.
2. Install the fuel tank cap adaptor.
3. Connect the EVAP pressure/purge diagnostic station and vehicle fuel fill cap to the fuel tank cap adaptor.
4. Turn ON the ignition, with the engine OFF.
5. Use a scan tool in order to seal the EVAP system.
6. Using the EVAP diagnostic station, attempt to pressurize the EVAP system to the specified value.
7. Rotate the EVAP diagnostic station rotary switch to the OFF/HOLD position.

Were you able to obtain and hold the specified value for 1 minute?

5 in H2O

Go to Step 12

Go to Step 13

12 | Compare the EVAP Diagnostic Station Pressure gauge value to the scan tool fuel tank pressure (FTP) sensor value. Does the EVAP Pressure/Purge Diagnostic Station gauge value correspond to the FTP sensor value on the scan tool? | -- | Go to Step 14 | Go to Step 29
13 | With the J 41413 , continuously attempt to pressurize the EVAP system. Important: It may be necessary to partially lower the fuel tank to inspect the components located in the upper portion of the tank. With the ultrasonic leak detector, inspect for leaks in the following locations:

• | The EVAP system purge pipe. Refer to Evaporative Emission Hoses/Pipes Replacement - Engine/Chassis .

• | The EVAP vapor pipe. Refer to Evaporative Emission Hoses/Pipes Replacement - Canister/Fuel Tank .

• | The EVAP vent hose/pipe

• | The fuel fill pipe/hose and fuel fill cap

• | The EVAP canister. Refer to Evaporative Emission Canister Replacement .

• | The EVAP canister vent valve. Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement .

• | The EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement .

• | The fuel sender assembly and/or seal. Refer to Fuel Sender Assembly Replacement .

• | The FTP sensor seal. Refer to Fuel Tank Pressure Sensor Replacement .

• | The fill limiter vent valve, pressure relief valve, rollover valves, and fuel tank. Refer to Fuel Tank Replacement .

Did you find and repair the condition?

--

Go to Step 31

Go to Diagnostic Aids

14 |

1. Monitor the EVAP Diagnostic Station pressure gauge.
2. Disconnect the EVAP purge pipe from the EVAP canister.

Does the EVAP Pressure/Purge Diagnostic Station gauge decrease to near the specified value?

0 in H2O

Go to Step 24

Go to Step 15

15 |

1. Observe the pressure gauge on the EVAP Diagnostic Station.
2. Disconnect the EVAP vapor pipe from the EVAP canister.

Does the EVAP Pressure/Purge Diagnostic Station gauge decrease to near the specified value?

0 in H2O

Go to Step 28

Go to Step 25

16 | Test the control circuit of the EVAP purge valve for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 20
17 | Test the control circuit of the EVAP vent valve for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 20
18 | Test for poor connections at the harness connector of the EVAP purge valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 26
19 | Test for poor connections at the harness connector of the EVAP vent valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 27
20 | Test for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 30
21 | Inspect the vacuum source to the EVAP purge valve for blockage, cuts, or disconnects. Repair as necessary. Did you find and correct the condition? | -- | Go to Step 31 | Go to Step 26
22 | Repair the ignition voltage circuit of the EVAP purge valve for an open or short to ground. Refer to Wiring Repairs in Wiring Systems. Replace the fuse as necessary. Did you complete the repair? | -- | Go to Step 31 | --
23 | Repair the ignition voltage circuit of the EVAP vent valve for an open or short to ground. Refer to Wiring Repairs in Wiring Systems. Replace the fuse as necessary. Did you complete the repair? | -- | Go to Step 31 | --
24 | Repair the restriction in the EVAP purge pipe. Refer to Evaporative Emission System Cleaning . Did you complete the repair? | -- | Go to Step 31 | --
25 | Repair the restriction in the EVAP vapor pipe. Did you complete the repair? | -- | Go to Step 31 | --
26 | Replace the EVAP purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 31 | --
27 | Replace the EVAP vent valve. Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 31 | --
28 | Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement . Did you complete the replacement? | -- | Go to Step 31 | --
29 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 31 | --
30 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 31 | --
31 |

1. Turn ON the ignition, with the engine OFF.
2. With a scan tool, command the EVAP vent valve ON.
3. Pressurize the EVAP system to the specified value with the J 41413 .
4. Place the control knob on the J 41413 to the OFF/HOLD position.
5. Monitor the EVAP system pressure on the EVAP pressure/purge diagnostic station for 5 minutes.

Does the EVAP system pressure remain constant?

--

Go to Step 32

Go to Step 4

32 | 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