P0440

DESCRIPTION
The EVAP Large Leak Test is based on applying vacuum to the Evaporative Emission (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 DTC P0440.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0110, P0112, P0113, P0115, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121, or P1122 are not set.
^ The system voltage is between 10-18 volts.
^ The start-up Engine Coolant Temperature (ECT) 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 start-up IAT temperature.
^ The startup Intake Air Temperature (IAT) 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 start-up ECT temperature.
^ The fuel tank level is between 15-85 percent.
^ The Barometric Pressure (BARO) is more than 75 kPa.
^ 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.

DIAGNOSTIC AIDS
^ Use the J 41413 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 J 41416 Ultrasonic Leak Detector.
^ A temporary blockage in the EVAP canister purge valve, the purge pipe, or the EVAP canister can cause an intermittent condition. In order to repair a blockage in the EVAP system, refer to Evaporative Emission (EVAP) System Cleaning. Service and Repair

TEST DESCRIPTION

Steps 8-13:

Steps 14-20:

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.
10. This step tests the EVAP canister purge valve for a restriction or blockage.
19. This step verifies that repairs are complete and that no other condition is present.