P0440

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

Refer to Emission Hose Routing Diagram EVAP System Overview.

SYSTEM DESCRIPTION
The Evaporative Emission (EVAP) system includes the following components:
^ The fuel tank
^ The EVAP canister vent valve
^ The fuel pipes and hoses
^ The fuel fill cap
^ The EVAP vapor pipes
^ The EVAP purge pipes
^ The EVAP canister
^ The EVAP purge valve

The EVAP LARGE LEAK TEST is based on applying vacuum to the EVAP system and monitoring the rate of vacuum decay. The Powertrain Control Module (PCM) uses the input from the Fuel Tank Pressure (FTP) sensor in order to determine the rate of vacuum decay. At an appropriate time, the PCM turns ON the EVAP canister purge valve and the EVAP vent valve, causing the purge valve to open and the vent valve to close. This seals the system and allows the engine to draw a vacuum on the system. At a calibrated time or vacuum level, the PCM turns OFF the purge valve, and tests the system vacuum. If the system is unable to achieve the calibrated vacuum level, the PCM will set DTC P0440.

The following conditions will set DTC P0440:
^ A missing, not completely installed, or malfunctioning 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 malfunctioning EVAP canister purge valve
^ A malfunctioning EVAP vent valve
^ An open ignition feed circuit to the EVAP vent or purge valve - This should also set DTC P0443 or P0449.
^ A damaged EVAP canister
^ A leaking fuel sender assembly O-ring
^ A leaking fuel tank or fuel filler neck

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0443 and P0449 are not active.
^ No Throttle Position (TP), Intake Air Temperature (IAT), Fuel Trim Pressure (FTP), electronic temperature control (ECT), or Manifold Absolute Pressure (MAP) sensor DTCs have set.
^ The system voltage is between 10.0-18.0 volts.
^ The startup ECT is not more than 4°C - 30°C (39°F - 86°F).
^ The startup ECT is not more than 8°C (14°F) more than the IAT startup temperature.
^ The startup IAT not more than 4°C - 30°C (39°F - 86°F).
^ The startup IAT is not more than 3°C (7°F) more than the ECT startup temperature.
^ The fuel tank level is between 15 percent and 85 percent for a 0.040 - 0.060 in. leak.
^ The Barometric Pressure (BARO) is more than 75 kPa.
^ The IAT is less than 30°C (86°F)
^ The Vehicle Speed Sensor (VSS) is less than 80 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 has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The history DTC will clear when the PCM turns off the MIL.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
Inspect for:
^ A malfunctioning or damaged EVAP canister
^ A loose, missing, defective, or incorrect fuel fill cap
^ Incorrectly routed, kinked, pinched, plugged, or defective EVAP system vacuum and vapor pipes
^ A charcoal release from the EVAP canister Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help to determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
1. The Powertrain On-Board Diagnostic (OBD) System Check prompts you to complete some of the basic checks and to store the Freeze Frame and Failure Records data on the scan tool, if applicable.
4. This step verifies that the EVAP system is not blocked from the EVAP purge valve to the EVAP canister.
5. This step verifies the system's ability to achieve 1.25 kPa (5 in. H2O), but does not verify its ability to hold vacuum.
11. This step tests the ability of the EVAP canister, fresh air hose and EVAP vent valve to hold and maintain vacuum.