P0440

Schematic:

SYSTEM DESCRIPTION
The EVAP Large Leak Test is based on applying vacuum to the Evaporative Emission (EVAP) system and monitoring vacuum decay. The Powertrain Control Module (PCM) uses the input from the fuel tank pressure sensor 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 the purge valve OFF, and tests the system vacuum. If the system is unable to achieve the calibrated vacuum level, the PCM will set DTC P0440.

The 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

CONDITIONS FOR RUNNING THE DTC
^ TP, IAT, FTP, ECT or MAP sensor DTCs are not set.
^ System voltage is between 10-18 volts.
^ Startup ECT is not more than 4°-30°C (39-86°F).
^ Startup ECT is not more than 8°C (14°F) more than IAT startup temperature.
^ Startup IAT not more than 4-30°C (39-86°F).
^ Fuel tank level is between 15-85 percent.
^ BARO is more than 75 kPa.
^ IAT is less than 30°C (86°F).
^ TPS between 7-35 percent.
^ VSS below 129 km/h (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.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF during the first consecutive trip in which the diagnostic has been run and Passed.
^ A last test failed (current DTC) clears when the PCM turns OFF the MIL.
^ The history DTC will clear after the PCM runs and passes 40 consecutive warm up cycles with no failure.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS

IMPORTANT: If charcoal release is detected, replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement

The following conditions will set DTC P0440:
^ An open ignition feed circuit to the EVAP vent or purge valve.
^ A fuel fill cap that is missing, improperly installed or malfunctioning.
^ Disconnected, damaged, pinched, or blocked conditions of one or more of the following components:
- The fuel tank vapor line
- The EVAP purge line
^ Malfunction of one or more of the following components:
- The EVAP canister purge valve
- An EVAP vent valve
^ Damage or disconnected condition of one or more of the following components:
- The EVAP canister
- An EVAP vent hose
^ A leak in or from one of the following components:
- The fuel sender assembly O-ring
- The fuel tank
- The fuel filler neck

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. If the condition is intermittent refer to Intermittent Conditions. Intermittent Conditions

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
4. This test verifies that the EVAP purge valve can be commanded ON and OFF.
5. This test verifies that the EVAP vent valve can be commanded ON and OFF.
10. Refer to the information supplied with the EVAP pressure/purge diagnostic cart on proper setup and adjustment procedures.
11. 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 9 test pressure) from forming in the fuel tank.
24. An EVAP pressure sensor that does not correctly respond to vacuum (or pressure) will cause this DTC to set.