DTC P0440. Pontiac Vibe

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2003 🢒 Vibe - FWD 🢒 DTC 🢒 DTC P0440

System Description

The DTC P0440 Evaporative Emission (EVAP) System diagnostic evaluates the operation of the EVAP control system. The powertrain control module (PCM) will command the EVAP vent valve ON, CLOSED, and the purge solenoid and the EVAP pressure switching solenoid ON, OPEN, with the engine running. This allows engine vacuum into the EVAP system. The PCM then commands the purge solenoid OFF, CLOSED, sealing the system. The PCM then monitors the fuel tank vapor pressure sensor signal in order to determine if there is vacuum decay. A rise or rapid increase in pressure indicates there is a large leak in the evaporative emission system. If the PCM detects the vacuum level was not achieved and vacuum decay was evident a DTC P0440 will set.

Conditions for Running the DTC

•	The barometric pressure (BARO) is more than 75 kPa.

•	The fuel level is between 25-75 percent.

•	The ECT sensor and the intake air temperature (IAT) sensor are near the same temperature at engine start.

•	The ECT sensor is at least 74°C (165°F) after engine warm up.

•	The vehicle has been driven for at least 20 minutes.

•	The EVAP canister purge solenoid has been open and the fuel tank pressure (FTP) sensor indicates a negative pressure in the fuel tank.

Conditions for Setting the DTC

The EVAP system is not able to achieve or maintain the expected vacuum pressure during the diagnostic test.

Action Taken When the DTC Sets

•	The PCM illuminates the malfunction indicator lamp (MIL) after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.

•	The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

Conditions for Clearing the MIL/DTC

•	The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.

•	A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.

•	A DTC can be cleared by using the scan tool Clear Information function.

Diagnostic Aids

•

To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. In order to improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT light.

•	A temporary blockage in the EVAP purge solenoid, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.

•

The test for leaks with smoke is performed with the system subjected to positive pressure. The trouble code diagnostic tests for a leak with vacuum or negative pressure. Perform the Purge/Seal test with the scan tool in order to test for leaks using vacuum pressure. Refer to Purge/Seal Function in Service Bay Test . If the Purge/Seal test fails, inspect the EVAP system o-ring seals for failure. O-ring seals can provide a good seal with pressure applied in one direction, but leak when the pressure is applied in the opposite direction.

•	Operating the vehicle in Check Mode will increase the ability of the powertrain control (PCM) module to detect engine control system malfunctions. Refer to Check Mode in Service Bay Test .

•	For intermittent conditions refer to Intermittent Conditions .

•	If the DTC cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This test verifies that the DTC P0440 is captured in the freeze frame/failure record list. When multiple EVAP system DTCs are set, the DTC stored in the freeze frame/failure record is the best diagnostic starting point.

This test verifies that the EVAP purge solenoid is electrically functional.

This test verifies that the EVAP vent solenoid is electrically functional.

This test verifies that the EVAP pressure switching solenoid is electrically functional.

The fuel filler pipe has two vent lines that allow for recirculation of fuel vapors between the fuel filler pipe and the fuel tank. Because of these vent lines the EEST can be connected to the EVAP service port for leak detection. Waiting until smoke is seen before plugging the EVAP canister drain hose speeds up the filling of the canister with smoke. Introducing smoke in between 60 second intervals of Nitrogen will speed up the filling of smoke in the fuel tank and filler pipe vapor space. This occurs because the pressure at which Nitrogen gas is applied is greater than the pressure at which smoke is introduced. The Nitrogen gas pushes the smoke that was just introduced through the canister and into the fuel tank. The EVAP vent solenoid DOES NOT have to be turned ON in order to test for leaks. A one way check valve located in the vent port of the EVAP canister provides containment of smoke and pressure within the EVAP system.

This test verifies that the fuel tank pressure (FTP) sensor is accurate. An FTP sensor that does not correctly respond to vacuum, or pressure may cause this DTC to set.

This step tests the functional operation of the EVAP pressure switching solenoid.

This step tests the functional operation of the EVAP vent solenoid.

This step tests the functional operation of the EVAP purge solenoid.

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics Evaporative Emissions Hose Routing Diagram

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

Install a scan tool.
Check for DTCs.

Is a DTC P0450 or P0451 present?

Go to DTC P0450 DTC P0451

Go to Step 3

Review the Freeze Frame/Failure Records
Diagnose the DTC captured in the Freeze Frame/Failure records first

Is DTC P0440 captured in the Freeze Frame/Failure records?

Go to Step 4

Go to Diagnostic Trouble Code (DTC) List

Inspect the EVAP system for the following conditions:

•	A loose, missing, or damaged service port schrader valve

•	A loose, incorrect, missing, or damaged fuel fill cap

•	A damaged EVAP purge solenoid

Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information.
Inspect the EVAP system for the following conditions:

•	Any disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses

•	A damaged EVAP vent solenoid or EVAP canister

Did you find and correct the condition?