P0440

Diagnostic Chart:

Electrical:

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 the vacuum to the EVAP system and monitoring the vacuum decay.

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. If 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 and set a DTC P0440:

^ A missing, malfunctioning, improperly installed, or loose fuel cap

^ A disconnected or malfunctioning fuel tank pressure sensor

^ 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

CONDITIONS FOR SETTING THE DTC

^ No MAP sensor DTCs

^ No TP sensor DTCs

^ No VSS DTCs

^ No HO2S DTCs

^ No ECT DTCs

^ DTC P0125 not active

^ No IAT sensor DTCs

^ No Fuel Level DTCs

^ The Fuel Level is greater than 12.5% and 87.5%

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

Cold Start Test

^ The ECT is greater than 3.75.°C but less than 30°C

^ The IAT is greater than 3.75°C but less than 30°C

^ 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 75 kPa

^ Fuel tank vacuum is less than 9 in. H20

^ Fuel level input test has passed

Warm Start Test

^ Cold start test failed

^ Fuel tank vacuum is less than 11 in. H20

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

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 MIL will turn OFF after one ignition cycle in which the diagnostic runs without a fault.

^ The Freeze Frame information and the history DTC will clear after one ignition cycle in which the diagnostic runs without a fault.

^ A scan tool cad clear the DTCs.

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 loose, damaged or misaligned fuel filler tube or fuel filler vent hose

^ A cracked or punctured EVAP canister

^ A damaged or disconnected EVAP purge line, vent hose or fuel tank vapor line

^ A kinked, pinched or plugged EVAP Purge Line, 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

Refer to EVAP Control System Diagnosis before starting repairs. System Diagnosis - EVAP Control

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.