For 1990-2009 cars
Engine Controls Components
Power, Ground, EVAP, and EGR
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice

### Circuit Description

The evaporative emissions (EVAP) system includes the following components:

• | The fuel tank

• | The EVAP vent solenoid

• | The fuel tank pressure sensor

• | The fuel pipes and hoses

• | The fuel vapor lines

• | The fuel cap

• | The EVAP canister

• | The purge lines

• | The EVAP canister purge solenoid valve

• | The EVAP service port

The evaporative emission system is tested by applying vacuum to the EVAP system and by monitoring for a vacuum decay. The PCM monitors the vacuum level through the fuel tank pressure sensor signal. At an appropriate time, the EVAP canister purge valve and the EVAP vent solenoid are turned on, allowing the engine to draw a small vacuum on the entire evaporative emission system. After the desired vacuum level has been achieved, the EVAP canister purge valve will turn off, sealing the system. DTC P0440 will set because the PCM is not detecting the expected vacuum. This can be caused by the following conditions:

• | A missing, incorrect, or malfunctioning fuel cap.

• | A malfunctioning or disconnected fuel tank pressure sensor.

• | A disconnected, damaged, or restricted EVAP purge line.

• | A disconnected or damaged EVAP vent hose.

• | A disconnected, damaged, or restricted fuel tank vapor line.

• | The disconnected or malfunctioning EVAP canister purge valve.

• | The disconnected or malfunctioning EVAP vent solenoid.

• | An open ignition feed circuit to the EVAP vent valve or to the purge solenoid.

• | A damaged EVAP canister

• | A leaking fuel sender assembly O-ring

• | A leak in the fuel filler neck or the fuel tank.

### Conditions for Running the DTC

• | The following DTCs are not set: P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0452, P0453, P0502, P0503, P0601, P0602, P1621 and P1133.

• | The BARO is more than 75 kPa.

• | The intake air temperature (IAT) is between 5°C and 29°C (41°F and 84°F) at engine start up.

• | The engine coolant temperature (ECT) is between 5°C and 29°C (41°F and 84°F) at engine start up.

• | The IAT is not more than 1°C (2°F) more than the ECT at start up.

• | The ECT is not more than 7°C (12°F) more than the IAT at start up.

• | The fuel tank level is between 26 percent and 74 percent.

• | The throttle position (TP) is between 7 percent and 35 percent.

• | The EVAP solenoid is at 40 percent PWM.

### Conditions for Setting the DTC

The EVAP system is unable to detect a vacuum during the diagnostic test.

### Action Taken When the DTC Sets

• | The malfunction indicator lamp (MIL) will illuminate.

• | The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.

• | A history DTC stores.

### Conditions for Clearing the MIL/DTC

• | The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs and passes.

• | A history DTC will clear after 40 consecutive warm up cycles without a malfunction.

• | Use a scan tool to clear the DTCs.

### Diagnostic Aids

Although this DTC is considered a type A diagnostic, the DTC acts like a type B diagnostic under certain conditions. Whenever this diagnostic reports that the system has passed, or if the battery is disconnected, the diagnostic must fail twice before setting a DTC. The initial failure is not reported to the diagnostic executive or displayed on a scan tool. A passing system always reports to the diagnostic executive immediately.

If DTC P0460, P0461, P0462 or P0463 are set along with an EVAP System DTC, the EVAP DTC cannot be considered valid until you repair and clear the DTC P0460, P0461, P0462 or P0463.

Inspect the following components for the indicated conditions:

• | Verify that the O-rings at the EVAP canister fuel vapor and the purge line fittings are not missing or damaged.

• | Inspect the PCM harness connectors for the following conditions:

- | Any backed out terminals

- | Any incorrect mating

- | Any broken locks

- | Any incorrectly formed terminals or damaged terminals

- | A poor terminal-to-wire connection

• | Inspect the wiring harness to the following components for an intermittent open or a short:

- | The EVAP vent solenoid

- | The EVAP canister purge valve

- | The fuel tank pressure sensor

### Test Description

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

1. If a vent solenoid or canister purge valve electrical malfunction is present, the purge system will not operate correctly. Repairing the electrical malfunction will likely correct the condition that set DTC P0440.

2. This step tests for a skewed fuel tank pressure sensor at the ambient pressure. By disconnecting the fuel tank vapor line you are relieving the fuel tank pressure. If pressure is read, then either the sensor is skewed or the lines are plugged, pinched, or kinked.

3. This step confirms that the lines are OK and the problem is in the sensor.

4. This step verifies that the fuel tank pressure sensor accurately reacts to the EVAP system pressure changes.

5. This step tests for a stuck closed EVAP canister purge valve.

6. This step ensures that a sufficient source vacuum is present at the EVAP canister purge valve.

7. This step ensures a proper system integrity.

#### DTC P0440-Evaporative Emission (EVAP) Control System

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Are DTC P0452, P0453, P0460 or P0461 set? | -- | Go to Diagnostic Trouble Code (DTC) List/Type | Go to Step 3
3 |

1. Inspect for a missing, loose, or incorrect fuel cap.
2. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 4

4 | With the scan tool, command the EVAP canister purge valve and the vent solenoid on and off. Does the purge valve and the vent solenoid click when commanded on and off? | -- | Go to Step 5 | Go to Powertrain Control Module Outputs Diagnosis
5 |

1. Turn off the ignition.
2. Disconnect the fuel tank vapor line at the EVAP canister.
3. Turn on the ignition, with the engine off.
4. With the scan tool observe the fuel tank pressure sensor value.

Is the fuel tank pressure within the specified value range?

-0.32 - +0.32 kPa

(-1.28 - +1.28 in. H2O)

Go to Step 7

Go to Step 6

6 |

1. Turn off the ignition.
2. Inspect the vapor line from the fuel tank to the EVAP canister for any restrictions.
3. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 20

Go to DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage

or

DTC P0453 Fuel Tank Pressure Sensor Circuit High Voltage

7 | Important:: Before continuing with this diagnosis, zero the EVAP Pressure and the Vacuum gauges on the J 41413 EVAP pressure/purge diagnostic station . Read the temperature variation instructions and refer to the tool operating instructions.

1. Reconnect the fuel tank vapor line.
2. Connect the J 41413 EVAP pressure/purge diagnostic station to the EVAP service port.
3. Command the EVAP vent solenoid on, with the scan tool.

Important:: Do not exceed the pressure in the specified value.

4. Pressurize the EVAP system to the specified value, with the switch in the HOLD position monitor the pressure on the gauges.

Can the specified value be achieved?

1.25 kPa

(5 in. H2O)

Go to Step 8

Go to Step 10

8 |

1. Maintain the pressure at the first specified value.
2. Observe the Fuel Tank Pressure value on the scan tool.

Does the fuel tank pressure decrease to less than the second specified value within 2 minutes?

1.25 kPa

(5 in. H2O)

.96 kPa (3.85 in. H2O)

Go to Step 12

Go to Step 9

9 | Important:: Review the temperature variation instructions for the EVAP pressure/purge diagnostic station before performing this step.

1. Turn off the ignition.
2. Install the J 41415-40 fuel tank cap adapter.
3. Connect the J 41413 EVAP pressure/purge diagnostic station to the fuel tank cap adapter.
4. Turn on the ignition, with the engine off.
5. Command the EVAP System Seal function on with the scan tool.

Important:: Do not exceed the pressure in the first specified value.

6. Pressurize the EVAP system to the first specified amount and monitor the pressure on the gauge.

Does the pressure decrease to less than the second specified value within 2 minutes?

3.74 kPa (15 in. H2O)

2.49 kPa (10 in. H2O)

Go to Step 10

Go to Step 11

10 |

1. Disconnect the following lines from the EVAP canister.

• | The fuel tank vapor line

• | The EVAP purge line

2. Cap the fuel tank vapor line fitting at the canister.
3. Connect a hand vacuum pump to the EVAP purge line fitting at the canister.
4. Commanded the EVAP vent solenoid on with the scan tool.
5. Apply the specified amount of vacuum to the EVAP canister.

Can vacuum be achieved and maintained at the specified value?

17 kPa

(5 in. Hg)

Go to Step 15

Go to Step 14

11 |

1. Visually and physically inspect for the following conditions:

• | A restricted fuel tank vapor line

• | A restricted EVAP purge line

• | A restricted Purge Valve

2. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 20

Go to DTC P0452 Fuel Tank Pressure Sensor Circuit Low Voltage or DTC P0453 Fuel Tank Pressure Sensor Circuit High Voltage

12 |

1. Disconnect the EVAP canister purge valve vacuum supply hose at the valve.
2. Connect a hand vacuum pump to the valve.
3. Apply the specified amount of vacuum.
4. Command the EVAP purge valve on with the scan tool.

Does the EVAP canister purge valve release the vacuum?

34 kPa (10 in Hg)

Go to Step 13

Go to Step 17

13 |

1. Connect the vacuum gauge on the J 41413 EVAP pressure/purge diagnostic station to the vacuum source line.
2. Start the engine.
3. Stabilize the engine RPM near 2500 RPM.
4. Momentarily snap the throttle open, then allow the throttle to return to idle.
5. Observe the vacuum gauge.

Did the vacuum exceed the second specified value when the throttle closed?

33.86 kPa (10 in. Hg)

Go to Diagnostic Aids

Go to Step 18

14 |

1. Visually and physically inspect for the following conditions:

• | A disconnected vent hose

• | A damaged vent hose

• | A damaged EVAP canister

2. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

15 |

1. Turn off the ignition.
2. Visually and physically inspect for the following conditions:

• | A leaking fuel tank filler neck

• | A disconnected fuel tank vapor line

• | A leaking fuel tank vapor line

• | A disconnected EVAP purge line

• | A damaged EVAP purge line

• | The quick-connect O-rings for the EVAP lines.

3. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 16

16 |

1. Reconnect any components that were previously disconnected.
2. Turn on the ignition, with the engine off.
3. Command the EVAP vent solenoid on with the scan tool.
4. With the station connected to the EVAP service port, continuously attempt to pressurize the EVAP system by leaving the station control knob in the pressurized position.
5. Use the J 41416 ultrasonic leak detector to locate any leaks in the EVAP system. It may be necessary to partially lower the fuel tank in order to examine the top tank connections.
6. If a problem is found, repair as necessary.

Did you find and correct the condition?

--

Go to Step 20

--

17 |

1. Turn off the ignition.

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.

2. Replace the EVAP canister purge valve. Refer to the Evaporative Emission Canister Purge Solenoid Valve Replacement .
3. If carbon particles are found in the component, refer to Evaporative Emission System Cleaning .

Did you complete the replacement?

--

Go to Step 20

--

18 |

1. Turn off the ignition.
2. Locate and repair the cause of no vacuum to the EVAP canister purge valve.

Did you find and correct the condition?

--

Go to Step 20

--

19 |

1. Turn off the ignition.

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.

2. Replace the EVAP vent solenoid. Refer to Evaporative Emission Vent Valve Replacement .
3. If carbon particles are found in the component refer to Evaporative Emission System Cleaning .

Did you complete the replacement?

--

Go to Step 20

--

20 | Important:: Review the temperature variation instructions for the EVAP pressure/purge diagnostic station before performing this step.

1. Turn off the ignition.
2. Install the J 41415-40 fuel tank cap adapter.
3. Connect the J 41413 EVAP pressure/purge diagnostic station to the fuel tank cap adapter.
4. Turn on the ignition, with the engine off.
5. Command the EVAP System Seal function on with the scan tool.

Important:: Do not exceed the pressure given in the first specified value.

6. Pressurize the EVAP system to the first specified value and monitor the pressure on the gauge.

Does the pressure decrease to less than the second specified value within 2 minutes?

3.74 kPa (15 in. H2O)

2.49 kPa (10 in. H2O)

Go to Step 3

Go to Step 21

21 |

1. Use a scan tool to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK