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 Emission (EVAP) system includes the following components:
^ The fuel tank
^ The EVAP vent valve
^ The fuel tank pressure sensor
^ The fuel pipes and hoses
^ The vapor lines
^ The fuel cap
^ The EVAP canister The purge lines
^ The EVAP purge valve

The evaporative leak detection diagnostic strategy is based on applying a vacuum to the EVAP system and monitoring the vacuum decay rate. The VCM monitors the vacuum level via the fuel tank pressure sensor input. At an appropriate time, the EVAP purge valve and the EVAP vent valve turn ON, allowing the engine vacuum to draw a small vacuum on the entire evaporative emission system. If a sufficient vacuum level cannot be achieved, a large leak or a malfunctioning EVAP purge valve is indicated. The following conditions can cause this problem:
^ A disconnected or malfunctioning fuel tank pressure sensor
^ A missing, malfunctioning, or improperly installed fuel cap
^ A disconnected, damaged, pinched, or blocked EVAP purge line
^ A disconnected or damaged EVAP vent hose
^ A disconnected, damaged, pinched, or blocked fuel tank vapor line
^ A disconnected or malfunctioning EVAP purge valve
^ A disconnected or malfunctioning EVAP vent solenoid
^ An open ignition feed circuit to the EVAP vent valve or purge valve
^ A damaged EVAP canister
^ A leaking fuel sender assembly O-ring
^ A leaking fuel tank or fuel filler neck

Any of the above conditions can set DTC P0440.

CONDITIONS FOR RUNNING THE DTC
^ No active Manifold Absolute Pressure (MAP) sensor DTCs.
^ No active Throttle Position (TP) sensor DTCs.
^ No active Vehicle Speed Sensor (VSS) DTCs.
^ No active Heated Oxygen Sensor (HO2S) DTCs.
^ No active Engine Coolant Temperature (ECT) sensor DTCs.
^ No active Intake Air Temperature (IAT) sensor DTCs
^ DTC P0125 is not active.
^ The system voltage is 10 - 17 volts
^ The fuel level is 12.5 - 87 percent.
^ The ECT is 4°C - 30°C (39°F - 86°F)
^ The IAT is 4°C - 30°C (39°F - 86°F)
^ The cold start ECT minus IAT is less than the following:
1.5°C when the IAT is more than the ECT
8°C when the ECT is more than the IAT
^ The Barometric Pressure (BARO) is more than 73 kPa

CONDITIONS FOR SETTING THE DTC
The EVAP system is unable to generate a vacuum of more than a calibrated value over a specified period of time.

ACTION TAKEN WHEN THE DTC
^ This is a type A DTC that behaves like a B type, in which the VCM illuminates the Malfunction Indicator Lamp (MIL) during the second key cycle.
^ The VCM stores the conditions that were present when the DTC sets as a Freeze Frame and Failure Records data.

CONDITIONS FOR CLEARING THE MIL OR DTC
^ The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed.
^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle.
^ Use a scan tool in order to clear the DTCs.

DIAGNOSTIC AIDS

IMPORTANT: An accurate indication of the fuel level is required for the VCM to properly pass or fail this DTC. Always diagnose fuel level sensor DTCs before performing this DTCs diagnostic table. Always check for fuel level sensor DTCs stored in history.

Check for the following conditions:
^ A missing, damaged, incorrect, or improperly installed fuel cap
^ Any missing or damaged O-rings at the EVAP canister fuel vapor and purge line fittings
^ A cracked or punctured EVAP canister
^ A damaged or disconnected EVAP purge line, vent hose, or fuel tank vapor line
^ Any incorrectly routed or damaged EVAP system purge and vapor lines
^ A poor connection at the VCM. Inspect the harness connectors for the following conditions:
- Any backed-out terminals
- Any improper mating
- Any broken locks
- Any improperly formed or damaged terminals
- Any poor terminal-to-wire connections
^ A damaged harness. Inspect the wiring harness to the EVAP vent valve, the EVAP purge valve, and the fuel tank pressure sensor for an intermittent, an open, or a short circuit.
^ A kinked, pinched, or plugged EVAP purge or fuel tank vapor line. Verify that the lines are not restricted.

Refer to Evaporative Emission (EVAP) System Cleaning before starting repairs.

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
The numbers below refer to the step numbers on the diagnostic table.
3. Inspect the service port. Make sure that the valve core is not damaged. If the service port is suspect of leakage perform the following procedure:

Disconnect the purge line from the EVAP purge valve.

Connect a hand vacuum pump to the service port by placing the hose/adaptor over the unthreaded end portion of the service port.

Apply vacuum to 5 inches Hg. If the vacuum does not hold replace the entire purge line which contains the service port.
4. If the vehicle passes the Service Bay Test then an intermittent leak or restriction had occurred. Check the fuel tank cap for a possible loose or missing condition that may have caused this DTC to set.

If the Service Bay Test can not be run, proceed to Step 5. If a fault is not currently present the diagnostic table steps will return you to Step 3.
9. Refer to the information supplied with the EVAP pressure/purge diagnostic chart on proper setup and adjustment procedures.
10. With pressure applied it may be necessary to disconnect the EVAP lines at the components to verify that a line or component is not restricted. A restriction would prevent a vacuum (or the Step 9 test pressure) from forming in the fuel tank.
22. An EVAP pressure sensor that does not correctly respond to vacuum will cause this DTC to set.

The EVAP pressure sensor monitors a range from 7.5 inches H2O of pressure to -17.5 inches H2O of pressure.