P0440

DESCRIPTION
The EVAP large leak test applies vacuum to the Evaporative Emission (EVAP) system and monitors vacuum decay. The Powertrain Control Module (PCM) monitors the Fuel Tank Pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the PCM turns the EVAP canister purge valve ON (open) and the EVAP vent valve ON (closed). This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the PCM turns the purge valve OFF (closed), sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, DTC P0440 will set.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1120, P1220 or P1221 are not set.
^ The ignition voltage is between 10-18 volts.
^ The Barometric Pressure (BARO) is more than 75 kPa.
^ The fuel level is between 15-85 percent.
^ The Engine Coolant Temperature (ECT) is between 4-30°C (39-86°F).
^ The Intake Air Temperature (IAT) is between 4-30°C (39-86°F).
^ The start up ECT and the IAT are within 9°C (16°F) of each other.
^ The Vehicle Speed Sensor (VSS) is less than 121 km/h (75 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 ran 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 Malfunction Indicator Lamp (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
^ Use the J41413 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 J41416 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.
^ 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

Steps 1-7:

Steps 8-12:

Steps 13-18:

The numbers below refer to the step numbers on the diagnostic table.
4. This step verifies that a failure condition is active.
5. This step is used to verify if a leak is present.
6. This step verifies proper operation of the Fuel Tank Pressure (FTP) sensor.
9. This step tests the EVAP canister purge valve for a restriction or blockage.