P0440
Schematic:
CIRCUIT DESCRIPTION
The PCM tests the EVAP system for the following conditions:
^ Large and small leaks
^ Excess vacuum
^ Purge flow during non-commanded conditions
^ Fuel Level and Fuel Pressure sensor faults
^ EVAP Purge and Vent Valve faults
The PCM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. The PCM commands both the EVAP Purge Solenoid and the EVAP Vent Valve ON when the Conditions for Running the DTC are met in order to apply an engine vacuum to the EVAP system. The PCM commands the EVAP Purge Solenoid OFF once the system has reached a predetermined level of vacuum. This test verifies if a vacuum can be achieved in the EVAP system. Failure to develop a vacuum may be caused by a large leak or a restriction. This DTC sets after twice failing the above test.
CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0420, P0430, P0500, P0502, P0503, P0562, P0563, and HO2S DTCs are not set.
^ The ignition voltage is between 10 volts and 17 volts.
^ The barometric pressure is more than 75 kPa.
^ The fuel level is between 15 percent and 85 percent of full capacity.
^ The engine coolant temperature is between 4°C (39°F) and 30°C (86°F).
^ The intake air temperature is between 4°C (39°F) and 30°C (86°F).
^ The start up engine coolant and intake air temperatures are within 9°C (16°F) of each other.
CONDITIONS FOR SETTING THE DTC
IMPORTANT: This DTC does NOT report a first failed test. A first fail of this DTC will have a scan tool status as Not Run. Use the scan tool data display parameter of EVAP Test Result to determine if this DTC has failed or passed for this ignition cycle.
The EVAP system cannot develop a vacuum that is more than a predetermined value.
ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame and/or the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the Malfunction Indicator Lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the MIL/DTC.
DIAGNOSTIC AIDS
IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
^ For any test that requires probing the PCM or a component harness connector, use the J 35616-A connector test adapter kit. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams.
An accurate indication of fuel level is required for the PCM to properly Pass or Fail this DTC. Always diagnose fuel level sensor DTCs before performing this DTC diagnostic table. Always inspect for fuel level sensor DTCs stored as History.
Perform a physical inspection of the EVAP system. Inspect for the following conditions:
^ A loose, missing, defective, or incorrect fuel tank cap
^ A loose or missing EVAP service port cap.
^ A loose, missing, or damaged schrader valve.
^ Incorrectly routed or defective EVAP system vacuum and vapor lines
^ A malfunctioning or damaged vapor canister
^ A damaged fuel sender O-ring
Inspect for charcoal release from the vapor canister. Refer to the EVAP System Cleaning procedure.
Excessive resistance in any circuit related to the EVAP system may cause this DTC to set. Listen for an audible click as the EVAP vent solenoid and the EVAP purge solenoid are commanded using the scan tool. If either component does not operate when commanded ON and OFF, and no other DTC is set, inspect the related circuits for excessive resistance.
The vacuum and pressure in the EVAP system is measured in inches of H2O (water). Most gauges measure vacuum in inches of Hg (mercury) and pressure in psi (pounds per square inch). The table shows how the values compare.
CONDITIONS FOR RUNNING THE SERVICE BAY TEST
^ The Service Bay Test may have to be performed in cold ambient air temperatures when the vehicle is running a winter grade fuel. The scan tool displays a message when the service bay test does not run.
^ The battery voltage is between 10.5 and 17.5 volts.
^ The fuel level is between 15 percent and 85 percent of the full capacity.
^ The engine temperature is between 3.5°C (38°F) and 35°C (95°F)
^ The scan tool displays Test Aborted if any of the above conditions are not met.
^ Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.
^ For an intermittent, refer to Symptoms. Symptom Related Diagnostic Procedures
TEST DESCRIPTION
Steps 1 - 7:
Steps 8 - 12:
Steps 13 - 22:
The numbers below refer to the step numbers on the Diagnostic Table.
3. It may be necessary to partially lower the fuel tank to inspect the upper portion of the tank and the EVAP line connections.
4. An intermittent leak or restriction is indicated if the vehicle passes the Service Bay Test. A fuel tank cap that is loose or off causes this DTC to set.
If the Service Bay Test can not be run, proceed to step 5. If a fault is not currently present the diagnostic table steps will return you to step 3.
12. This step tests for a leak at the top of the fuel tank, at the fuel filler hose, and the fuel cap. Place the ultrasonic leak detector in these areas. Refer to the information supplied with the EVAP pressure/purge diagnostic cart on proper setup and adjustment procedures.
13. With pressure applied it may be necessary to disconnect the EVAP lines at the components to verify that a line or component is not restricted. A restriction would prevent a vacuum (or the Step 10 test pressure) from forming in the fuel tank.
19. A Fuel Tank Pressure sensor that does not correctly respond to pressure (or vacuum) causes this DTC to set.
The Fuel Tank Pressure sensor range is from 7.5 in. H2O of pressure to -17.5 in. H2O of pressure (vacuum).
In order to test the Fuel Tank Pressure sensor for vacuum response, command the EVAP Purge Solenoid Valve ON with the engine running and quickly SEAL the system. Leaving the EVAP Purge Solenoid Valve ON for a longer period of time allows a greater level of vacuum to develop.