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 vapor lines
^ The fuel cap
^ The evaporative emission canister
^ The purge lines
^ The EVAP purge solenoid

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 solenoid and the EVAP vent solenoid 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 system malfunction is indicated. The following conditions may cause this problem:
^ A disconnected or malfunctioning fuel tank pressure sensor.
^ A missing, malfunctioning, improperly installed, or loose 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 solenoid.
^ A disconnected or malfunctioning EVAP vent solenoid.
^ An open ignition feed circuit to the EVAP vent or purge solenoid.
^ A damaged EVAP canister.
^ A leaking fuel sender assembly O-ring.
^ A leaking fuel tank or fuel filler neck.

Any of the above conditions may set a DTC P0440.

CONDITIONS FOR RUNNING THE DTC
^ No active MAP sensor DTCs
^ No active TP sensor DTCs
^ No active VS sensor DTCs
^ No active HO2S DTCs
^ No active ECT sensor DTCs
^ No active IAT sensor DTCs
^ DTC P0125 not active
^ The system voltage is between 10 and 17 volts.
^ The fuel level is between 12.5 percent and 87 percent.
^ The ECT is between 4°C and 30°C (39°F to 86°F).
^ The IAT is between 4°C and 30°C (39°F to 86°F).
^ The cold start temperature difference (ECT minus IAT) is less than 1.5°C when the IAT is more than the ECT or 8°C when the ECT is more than the IAT.
^ The BARO is more than 73 kPa.

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

ACTION TAKEN WHEN THE DTC SETS
^ This is a type A DTC that behaves like a B type, in which the VCM illuminates the MIL during the second key cycle.
^ The VCM stores the conditions that were present when the DTC sets as a Freeze Frame and Fail 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 it 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 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 loose, missing, damaged, incorrect, or improperly installed fuel cap
^ Missing or damaged O-rings at 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
^ Incorrectly routed or damaged EVAP system purge and vapor lines
^ A faulty connection at the VCM. Inspect the harness connectors for the following conditions:
- Backed out terminals Improper mating
- Broken locks
- Improperly formed or damaged terminals
- A faulty terminal to wire connection
^ A damaged harness: Inspect the wiring harness to the EVAP vent solenoid, EVAP purge solenoid, and the fuel tank pressure sensor for an intermittent, an open, or a short circuit.
^ A kinked, pinched, or plugged vacuum source, EVAP purge, or fuel tank vapor line. Verify that the lines are not restricted.

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

Reviewing the Fail 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. Ensure that the valve core is not damaged. If you suspect the service port of leakage, use the following procedure:

Disconnect the purge line from the EVAP purge solenoid valve.

Connect a hand vacuum pump to the service port by placing the hose and 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 a restriction had occurred. Check the fuel tank cap for a possible loose or off condition that may have caused this DTC to set.

If you cannot run the Service Bay Test, 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 Evaporative Emissions (EVAP) pressure and purge diagnostic cart for proper setup and adjustment procedures.
10. With pressure applied, you may need to disconnect the EVAP lines at the components in order to verity that a line or a component is not restricted. A restriction would prevent a vacuum from forming in the fuel tank. A restriction would also prevent the step 9 test pressure from forming in the fuel tank.
22. An EVAP pressure sensor that does not correctly respond to either vacuum or pressure 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 vacuum.