P0440

DESCRIPTION
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 the EVAP canister purge valve ON (open) and the EVAP canister vent valve ON (closed). This allows the engine to draw a vacuum on the system. At a calibrated time or vacuum level, the PCM turns the purge valve OFF (closed), and tests the system vacuum. If the system is unable to achieve the calibrated vacuum level, the PCM will set Diagnostic Trouble Code (DTC) P0440.

CONDITIONS FOR RUNNING THE DTC
^ DTC P0107. P0108, P0110, P0112, P0113, P0115, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121 and P1122 not active.
^ The system voltage is between 10-18 volts.
^ The startup (ECT) engine coolant temperature is between than 4-30°C (39-86°F), but the start up ECT is not more than 8°C (14°F) more than the startup IAT temperature.
^ The startup (IAT) intake air temperature is between than 4-30°C (39-86°F), but the start up IAT is not more than 3°C (7°F) more than the startup ECT temperature.
^ The fuel tank level is between 15-85 percent.
^ The Barometric Pressure (BARO) is more than 75 kPa (10.8 psi).
^ The Vehicle Speed Sensor (VSS) is less than 128 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 illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A last test failed, or the current DTC, clears when the diagnostic runs and does not fail.
^ A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS
^ Use the EVAP pressure/purge diagnostic station in order to pressurize the EVAP system to aid in locating intermittent leaks.
^ Move all EVAP components while testing with the Ultrasonic Leak Detector.
^ A temporary blockage in the EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition. To repair a blockage in the EVAP system refer to Evaporative Emission (EVAP) System Cleaning.