P0440

Diagnostic Chart:

Wiring Diagram:

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 vacuum 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. It a sufficient vacuum level cannot be achieved, a large leak or a malfunctioning EVAP purge solenoid is indicated. The following conditions can 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 can set a DTC P0440.

CONDITIONS FOR SETTING THE DTC

^ No MAP sensor DTCs.

^ No TP sensor DTCs.

^ No VSS DTCs.

^ No HO2S DTCs.

^ No ECT DTCs.

^ The DTC P0125 not active

^ No IAT sensor DTCs.

^ The Fuel Level is between 12.5-87.5%.

^ The System Voltage is greater than 10 volts but less than 17 volts.

Cold Start Test

^ The ECT is greater than 4°C (39°F) but less than 30°C (86°F).

^ The IAT is greater than 4°C (39°F) but less than 30°C (86°F).

^ Cold Temperature difference (ECT - IAT):

Start up ECT is not more than 8.25°C greater than the start up IAT.

Start up IAT is not more than 1.5°C greater than the start up ECT

^ The Baro is greater than 72.5 kPa.

^ Fuel tank vacuum is less than 9 in. H2O.

Warm Start Test

^ Cold start test failed last trip and this trip.

^ Fuel tank vacuum is less than 11 in. H2O.

OR

If HC vapor is not present and the small leak test has failed.

^ Problem present for at least 1400 s.

ACTION TAKEN WHEN THE DTC SETS

^ The VCM illuminates the MIL during the second key cycle in which the diagnostic reports a fail.

^ The VCM stores the conditions which were present when the DTC sets as a Freeze Frame and Fail Records data.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The VCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.

^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle).

^ Use the scan tool Clear Information function.

^ Disconnect the VCM battery feed for 30 seconds.

DIAGNOSTIC AIDS

Check for the following conditions:

^ A loose, missing, damaged, 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 source vacuum line, EVAP purge line, vent hose or fuel tank vapor line

^ A poor connection at the VCM: Inspect the harness connectors for the following conditions:

- Backed out terminals

- Improper mating

- Broken locks

- Improperly formed or damaged terminals

- poor 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 open or 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 EVAP System Cleaning before starting 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. This step checks the fuel tank pressure sensor at atmospheric pressure.

4. This step determines if the EVAP system has a restriction or leak.

5. This step determines if there is a restriction in the Fuel Tank Vapor Line or Canister.

8. This step checks for a restriction in the EVAP Canister.