P0440

EVAP System Description
The evaporative emissions (EVAP) system includes the following components:
^ The fuel tank.
^ The EVAP vent valve/solenoid.
^ The fuel tank pressure sensor.
^ The fuel pipes and hoses.
^ The fuel fill cap.
^ The EVAP vapor lines.
^ The EVAP purge lines.
^ The EVAP canister.
^ The EVAP canister purge valve/solenoid.
The EVAP Large Leak Test Is based upon applying vacuum to the EVAP system and monitoring the vacuum decay. The PCM monitors the vacuum level via the fuel tank pressure sensor input. At an appropriate time, the EVAP canister purge valve/solenoid and the EVAP vent valve/solenoid are turned on, allowing engine vacuum to draw a small vacuum on the entire EVAP system. If a sufficient vacuum level cannot be achieved, a large leak or a faulty EVAP canister purge valve/solenoid is indicated. This may be caused by the following conditions:
^ A disconnected or faulty fuel tank pressure sensor.
^ A missing, incompletely installed, or faulty fuel fill 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 canister purge valve/solenoid.
^ A disconnected or faulty EVAP vent valve/solenoid.
^ An open ignition feed circuit to the EVAP vent or purge valve/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 may set DTC P0440.

Conditions for Running the DTC
^ None of the following DTCs are set:
- Throttle position (TP) sensor DTCs
- Intake air temperature (IAT) DTCs
- Manifold air pressure (MAP) DTCs
- ODM DTCs
^ The system voltage is between 9 and 16 volts.
^ The startup engine coolant temperature (ECT) is between 4°C and 30°C (40°F and 86°F).
^ The startup ECT is not over 8°C (14°F) more than the startup IAT.
^ The startup IAT is between 4°C and 30°C (40°F and 86°F).
^ The startup IAT is not over 2°C (4°F) more than the start-up ECT.
^ The fuel tank level is between 15% and 85%.
^ The BARO is greater than 75 kPa.

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

Important: Although this diagnostic is considered type A, the diagnostic acts like a type B diagnostic. Whenever the EVAP diagnostics report that a system has passed, or if the battery is disconnected, the diagnostic must fail during 2 consecutive cold start trips 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.

^ The powertrain control module (PCM) stores the conditions which were present when the DTC set as Freeze Frame data.
^ The PCM stores the conditions which were present when the DTC set as Fail Records data.

Conditions for Clearing the MIL/DTC
^ The PCM turns the MIL off when the diagnostic has run and the fault condition is no longer present.
^ A history DTC P0440 clears after 40 consecutive warm-up cycles have occurred without a fault.
^ This DTC may be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed.
^ The code clears if the fill cap is tightened or reinstalled.

Diagnostic Aids
Inspect for the following conditions:
^ A cracked or punctured EVAP canister.
^ A damaged or disconnected source vacuum line, EVAP purge line, vent hose, or fuel tank vapor line.
^ A faulty connection at the PCM. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections.
^ Inspect the wiring harness to the EVAP vent valve/solenoid, the EVAP purge valve/solenoid, and the fuel tank pressure sensor for an intermittent open or a short circuit.
^ Inspect for a kinked, pinched or plugged vacuum source, EVAP purge, or fuel tank vapor line. Verify that the lines are not restricted.
^ Use the following procedure in order to test for a carbon release condition that could plug the system:
1. Turn Off the ignition switch.
2. Remove the EVAP canister purge valve/solenoid.
3. Lightly tap the canister purge valve on a clean work area while looking for carbon particles exiting either of the vacuum ports.
4. If no carbon release is evident, reinstall the components and continue with the DTC P0440 diagnostic table. If carbon is being released from either component, continue with this service procedure.
5. Remove the charcoal canister from the vehicle.
6. Ensure that the main cylinder valve is turned Off on the J41413 EVAP purge/pressure diagnostic station.
7. 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.
8. Using a section of vacuum line, connect one end over the open threaded fitting of the EVAP purge/pressure diagnostic station pressure regulator.
9. Connect the remaining end to the purge valve 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.
10. Return the EVAP Pressure/Purge Diagnostic Station to its original condition by reinstalling the black hose that was disconnected in Step 7.
11. Replace the following components:
^ The EVAP canister purge valve.
^ The EVAP canister.
12. Proceed with the DTC P0440 diagnostic procedure.
Reviewing the Fail 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.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table:
1. The Diagnostic system check prompts you to complete some of the basic checks and store the freeze frame and failure records data on the Scan Tool if applicable.
2. If a vent valve or EVAP purge valve electrical malfunction is present, the purge system will not operate correctly. Repairing the electrical malfunction that caused the additional DTC to set will very likely correct the condition that set this DTC.
3. Checks for a fuel tank pressure sensor stuck high condition. The fuel tank pressure must be relieved by removing the canister line from the fuel tank or EVAP canister. The fuel fill cap will not relieve the fuel tank pressure due to a check valve in the filler neck. The check valve seals when pressure is applied to prevent vapors from escaping through the filler neck. The Scan Tool should read within ±1.0 in. H2O of the specified value.
4. Checks for a Large Leak in the EVAP system.
5. Verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes. The EVAP station is pressurizing a sensor that normally reads vacuum. The tech II reads high pressure at 0 volts and high vacuum at 5 volts. the Tech II can only read a max pressure of 6.0 inches of H2O (0 Volts). However the EVAP Service station can pressurize the system to much higher pressures. The Scan Tool value should be within +A 0.5 of the specified value.
6. Checks for a leaking EVAP canister line, or vent valve.
8. Checks for a stuck closed or plugged EVAP canister purge valve/solenoid
9. Checks for a leaking or stuck open EVAP canister purge valve/solenoid, The scan tool should read within ±1.0 in. HG of the specified value.
12. Checks for a leaking or stuck open EVAP canister purge valve/solenoid. The valve should be within ±1.0 in HG of the specified value.
17. Ensures that sufficient source vacuum is present at the EVAP canister purge valve/solenoid.
20. The EVAP station is pressurizing a sensor that normally reads vacuum. The Tech II reads high pressure at 0 volts and high vacuum at 5 volts. The Tech II can only read a max pressure of 6.0 inches of H2O (0 Volts). However the EVAP Service station can pressurize the system to much higher pressures. The Scan Tool value should be within ±0.5 of the specified value.