P0440
SYSTEM DESCRIPTIONThe control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge valve OPEN and the EVAP vent valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets.
The table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent valves.
CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0443, P0449, P0452, P0453, P1111, P1112, P1114, P1115, P1120, P1220, or P-1221 are not set.
^ The ignition voltage is between 10-18 volts.
^ The barometric pressure (BARO) is more than 75 kPa.
^ The fuel tank 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 IAT are within 9°C (16°F) of each other.
^ The vehicle speed sensor (VSS) is less than 121 km/h (75mph).
CONDITIONS FOR SETTING THE DTC
The EVAP system is not able to achieve or to maintain a vacuum during the diagnostic test.
ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE DTC
^ A current DTC Last Test Failed clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
^ Clear the DTC with a scan tool.
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 could cause an intermittent condition. In order to repair a blockage in the EVAP system, refer to Evaporative Emission (EVAP) System Cleaning.
^ Reviewing the Failure 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 8-10:
Steps 11-19:
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 FTP sensor.
11. This step tests the EVAP canister purge valve for a restriction or blockage.
17. This step verifies that repairs are complete and that no other condition is present.