P0440

DTC P0440

System Description

The 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 following 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, P0110, P0112, P0113, P0115, P0116, 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 engine coolant temperature (ECT) is between than 4-30°C (39-86°F).
- The intake air temperature (IAT) is between than 4-30°C (39-86°F).
- 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 121 km/h (75 mph).
- The start-up ECT and IAT are within 9°C (16°F).

Conditions for Setting the DTC

The EVAP system is not able to achieve or 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 MIL/DTC

- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- 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 emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

- Use the J 41413 EVAP Pressure and Purge Station in order to pressurize the EVAP system. 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. To repair a blockage in the EVAP system refer to Evaporative Emission System Cleaning.
- Reviewing the Freeze Frame/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

The numbers below refer to the step numbers on the diagnostic table.

4. 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.