P0440

DTC P0440 EVAP System (1 Of 3):

DTC P0440 EVAP System (2 Of 3):

DTC P0440 EVAP System (3 Of 3):

EVAP System:

Circuit Description
The evaporative system includes the following components:

^ The fuel tank.
^ The Evaporation Emission (EVAP) vent solenoid.
^ The fuel tank pressure sensor.
^ The fuel pipes and hoses.
^ The vapor lines.
^ The fuel cap.
^ The evaporative emission canister.
^ The purge lines.
^ The EVAP purge solenoid.

The evaporative leak detection diagnostic strategy is based on applying the vacuum to the EVAP system and monitoring the vacuum decay. The Vehicle Control Module (VCM) monitors the vacuum level via the fuel tank vacuum sensor input. At an appropriate time, the EVAP purge solenoid and the EVAP vent solenoid turn on, allowing the engine vacuum to draw a small vacuum on the entire evaporative emission system. If a sufficient vacuum level cannot be achieved, a large leak or a faulty EVAP purge solenoid is indicated. The following conditions can cause this problem:

^ A disconnected or faulty fuel tank pressure sensor
^ A missing, faulty, improperly installed, or loose fuel cap
^ A disconnected, damaged, pinched, or blocked EVAP purge line
^ A disconnected or damaged EVAP vent hose
^ A disconnected, damaged, pinched, or blocked fuel tank vapor line
^ A disconnected or faulty EVAP purge solenoid
^ A disconnected or faulty EVAP vent solenoid
^ An open ignition feed circuit to the EVAP vent or purge solenoid
^ A damaged EVAP canister
^ A leaking fuel sender assembly O-ring
^ A leaking fuel tank or fuel filler neck. Any of the above conditions can set a DTC P0440. This DTC is a type A DTC.

Conditions For Setting The DTC
The Following Conditions will set the DTC:

1. No Manifold Absolute Pressure (MAP) sensor DTCs.
2. No Throttle Position (TP) sensor DTCs.
3. No Vehicle Speed Sensor (VSS) DTCs.
4. No HO2S DTCs.
5. No Engine Coolant Temperature (ECT) DTCs.
6. The DTC P0125 not active.
7. No Intake Air Temperature (IAT) sensor DTCs.
8. No Fuel Level DTCs.
9. The Fuel Level is greater than 10% and 85%.
10. The System Voltage is greater than 10 volts but less than 17 volts.
11. The ECT is greater than 3.75°C (38.75°F) but less than 30°C (86°F).
12. The IAT is greater than 3.75°C (38.75°F) but less than 30°C (86°F).
13. Start up ECT is not more than 8.25°C (46.85°F) greater than the start up IAT.
14. Start up IAT is not more than 1.5°C (34.7°F) greater than the start up ECT.
15. The Baro is greater than 72.5 kPa.
16. The EVAP system is unable to achieve or maintain vacuum during the diagnostic test.

Action Taken When The DTC Sets

^ The VCM illuminates the Malfunction Indicator Lamp (MIL) during the second key cycle in which the diagnostic reports a fail.
^ The VCM stores the conditions which were present when the DTC set as Freeze Frame and Fail Records data.

Conditions For Clearing The MIL/DTC
The Following Conditions will clear the DTC:

1. The VCM turns the MIL OFF when the diagnostic has run and has not reported a failure for 3 consecutive warm-up cycles.
2. A history DTC P0440 clears after 40 consecutive warm-up cycles have occurred without a fault reported.
3. The DTC P0440 can be cleared by using the scan tool Clear Info function or by disconnecting the VCM battery feed for more than thirty seconds.

Diagnostic Aids
Check for the following conditions:

^ A loose, missing, damaged, or improperly installed fuel cap.
^ Missing or damaged 0-rings at EVAP canister fuel vapor and purge line fittings.
^ A cracked or punctured EVAP canister.
^ A damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
^ A poor connection at the VCM: Inspect the harness connectors for the following conditions:

- Backed out terminals.
- Improper mating.
- Broken locks.
- Improperly formed or damaged terminals.
- poor terminal to wire connection.

^ A damaged harness: Inspect the wiring harness to the EVAP vent solenoid EVAP purge solenoid and the fuel tank pressure sensor for an intermittent open or short circuit.
^ A kinked, pinched or plugged vacuum source, EVAP purge, or fuel tank vapor line. Verify that the lines are not restricted.

Refer to Carbon Particle Removal from EVAP System before starting repairs. Reviewing the Fail Records vehicle mileage since the diagnostic test last tailed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition. Service and Repair

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

2. This step checks the fuel tank pressure sensor at ambient pressure. The fuel tank pressure sensor is zeroed at every key on to compensate for changes in atmospheric pressure.
3. This step determines whether or not the EVAP system can be sealed sufficiently to be pressurized. If not, the large leak must be located and corrected before continuing with diagnosis.
4. This step verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes.
7. This step checks for a stuck closed EVAP purge solenoid.
8. This step ensures that sufficient source vacuum is present at the EVAP purge solenoid.