P0440

Evaporative System Circuit:

Circuit Description
The evaporative system includes the following components:
The evaporative leak detection diagnostic strategy is based on applying vacuum to the EVAP system and monitoring vacuum decay. The Powertrain Control Module (PCM) monitors the vacuum level via the fuel tank vacuum sensor input. At a calibrated time, the EVAP purge solenoid and the EVAP vent solenoid are turned "ON." This allows engine vacuum to draw a small vacuum on the entire evaporative emission system. Whenever a sufficient vacuum level cannot be achieved, a large leak or a faulty EVAP purge solenoid is indicated.

Conditions for Setting the DTC
- The BARO is greater than 70 kPa
- The intake air temperature is between 4°C and 30°C at engine start up
- The engine coolant temperature is between 4°C and 30°C at engine start up
- The Engine Coolant Temperature (ECT) sensor and Intake Air Temperature (IAT) sensor are within 4°C at engine start up
- Fuel tank level is between 15% and 85%
- The Throttle Position (TP) sensor is between 9 and 35%
- The engine run time is greater than 120 sec.
- The EVAP solenoid is enabled
- The EVAP system is unable to achieve or maintain vacuum during the diagnostic test. The amount of decay will vary with the fuel level.
- One or more of the following DTCs are not set P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0l32, P0133, P0134 and P1133.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn "OFF" after one ignition cycle in which the diagnostic runs without a fault.
- Freeze Frame information and the history DTC will clear after one ignition cycle in which the diagnostic runs without a fault.
- DTCs can be cleared by using a scan tool.

Diagnostic Aids
Check for the following conditions:
- Missing or damaged O-rings at the EVAP canister fuel vapor fittings and purge line fittings.
- Cracked EVAP canister.
- Damaged or disconnected source vacuum line, EVAP purge line, vent hose or fuel tank vapor line.
- Poor connection at the PCM. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals.
- Damaged harness. Inspect the wiring harness to the EVAP vent solenoid, the EVAP purge solenoid, and the fuel tank pressure sensor for an intermittent open or short circuit.
- Kinked, pinched or plugged vacuum source, EVAP purge, or fuel tank vapor line. Verify that the lines are not restricted.

NOTE: Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.

DTC P0440 - Evaporative (EVAP) System (1 Of 3):

DTC P0440 - Evaporative (EVAP) System (2 Of 3):

DTC P0440 - Evaporative (EVAP) System (3 Of 3):

Test Description
Numbers below refer to the step numbers on the Diagnostic Table.
1. The OBD System Check prompts the Technician to complete some basic checks and store the Freeze Frame Data and the Failure records on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. This information on the scan tool can be referred to later.
2. Whenever a vent solenoid or EVAP purge solenoid electrical fault is present, the purge system will not operate correctly. Repairing the electrical fault will very likely correct the condition that set DTC P0440.
3. Checks the fuel tank vacuum sensor at ambient pressure.
7. Determines whether the EVAP system can be sealed sufficiently to be pressurized. If not, the large leak must be located and corrected before continuing with diagnosis.
8. Verifies that the fuel tank pressure sensor accurately reacts to EVAP system pressure changes.
11. Checks for a stuck closed EVAP purge solenoid.
13. Ensures that sufficient source vacuum is present at the EVAP purge solenoid.