P0440

Diagnostic Chart (Part 1 Of 4):

Diagnostic Chart (Part 2 Of 4):

Diagnostic Chart (Part 3 Of 4):

Diagnostic Chart (Part 4 Of 4):

Schematic:

CIRCUIT DESCRIPTION
The evaporative system includes the following components:
^ The fuel tank
^ The EVAP vent solenoid
^ The fuel tank pressure sensor
^ The fuel pipes and hoses
^ The fuel vapor lines
^ The fuel cap
^ The EVAP canister
^ The purge lines
^ The EVAP canister purge solenoid valve
^ The EVAP service port

The Evaporative Emission (EVAP) system is checked by applying vacuum to the EVAP system and by monitoring for a vacuum decay. The Powertrain Control Module (PCM) monitors the vacuum level through the fuel tank pressure sensor signal. At an appropriate time, the EVAP canister purge valve and the EVAP vent solenoid are turned ON, allowing the engine to draw a small vacuum on the entire evaporative emission system. After the desired vacuum level has been achieved, the EVAP canister purge valve will turn OFF, sealing the system. DTC P0440 will set because the PCM is not detecting the expected vacuum. This can be caused by the following components with the conditions listed:
^ The fuel cap for the following conditions:
- Missing
- Malfunctioning
- Incorrect
^ The fuel tank pressure sensor for the following conditions:
- Disconnected
- Malfunctioning
^ The EVAP purge line for the following conditions:
- Disconnected
- Damaged
- Pinched
- Blocked
^ The EVAP vent hose for the following conditions:
- Disconnected
- Damaged
^ The fuel tank vapor line for the following conditions:
- Disconnected
- Damaged
- Pinched
- Blocked
^ The EVAP canister purge solenoid valve for the following conditions:
- Disconnected
- Malfunctioning
^ The EVAP vent solenoid for the following conditions:
- Disconnected
- Malfunctioning
^ An open ignition feed circuit to the following components:
- EVAP vent valve
- Purge solenoid
^ A damaged EVAP canister
^ A leaking fuel sender assembly O-ring
^ A leak in the following items:
- The fuel tank
- The fuel filler neck

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0452, P0453, P0502, P0503, P0601, P0602, P1621, and P1133 are not set.
^ The BARO is more than 75 kPa.
^ The Intake Air Temperature (IAT) is between 5°C and 29°C (41°F and 84°F) at engine start-up.
^ The Engine Coolant Temperature (ECT) is between 5°C and 29°C (41°F and 84°F) at engine start-up.
^ The Intake Air Temperature (IAT) is not more than 1°C (2°F) more than the Engine Coolant Temperature (ECT) at start-up.
^ The Engine Coolant Temperature (ECT) is not more than 7°C (12°F) more than the Intake Air Temperature (IAT) at start-up.
^ The fuel tank level is between 26 percent and 74 percent.
^ The TP sensor is between 7 percent and 35 percent.

CONDITIONS FOR SETTING THE DTC
The EVAP system is unable to detect vacuum during the diagnostic test.

ACTION TAKEN WHEN THE DTC SETS
^ The Malfunction Indicator Lamp (MIL) will illuminate.
^ The PCM will record the operating conditions at the time that the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.
^ A history DTC stores.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The MIL will turn OFF after one ignition cycle in which the diagnostic runs a pass.
^ Freeze Frame information and the history DTC will clear after one ignition cycle in which the diagnostic runs without a fault.
^ Use a scan tool to clear the DTCs.

DIAGNOSTIC AIDS
Although this DTC is considered a type A diagnostic, this DTC acts like a type B diagnostic during certain conditions. Refer to Serial Data Communications. Whenever this diagnostic reports that the system has passed or if the battery is disconnected, the diagnostic must fail twice before setting a DTC. The initial failure is not reported to the diagnostic executive or displayed on a scan tool. A passing system always reports to the diagnostic executive immediately. Data Link Connector

If a DTC P0461 is set along with an EVAP System DTC, the EVAP DTC cannot be considered valid until you repair and clear DTC P0461.

Inspect for the following conditions:
^ A missing or a damaged fuel cap
^ Missing or damaged O-rings at the EVAP canister fuel vapor and purge line fittings
^ A cracked or a punctured EVAP canister
^ A damaged or a disconnected source vacuum line, an EVAP purge line, a vent hose or a fuel tank vapor line
^ A faulty electrical terminal connection at the PCM. Inspect the harness electrical connectors for the following conditions: Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Faulty terminal to wire connection
^ A damaged harness - Inspect for an intermittent open circuit or a shorted circuit in the wiring harness to the following components:
- The EVAP vent solenoid
- The EVAP canister purge solenoid valve
- The fuel tank pressure sensor
^ Inspect the EVAP purge line and the fuel tank vapor line for the following conditions:
- kinks
- Pinches
- A plugged vacuum source
^ Refer to EVAP System Cleaning. Evaporative Emissions System

TEST DESCRIPTION
The numbers below refer to the step numbers on the Diagnostic Table.
4. If a vent solenoid or an EVAP canister purge valve electrical malfunction is present, the purge system will not operate correctly. Repairing the electrical malfunction will usually correct the condition that set DTC P0440.
5. This step tests the fuel tank pressure sensor at the ambient pressure.
7. This step determines whether or not the EVAP system is sealed sufficiently in order to be pressurized. If the system is riot sufficiently sealed, locate and correct the large leak before continuing with the diagnosis.
8. This step verifies that the fuel tank pressure sensor accurately reacts to the EVAP system pressure changes.
12. This step tests for a stuck closed EVAP canister purge solenoid valve.
14. This step ensures that a sufficient source vacuum is present at the EVAP canister purge solenoid valve.
20. This step insures proper system integrity.