DTC P0440 Evaporative Emission (EVAP) System. Cadillac Seville 1998

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 1998 🢒 Seville 🢒 DTC 🢒 DTC P0440 Evaporative Emission (EVAP) System

Engine Controls Components
Cell 20: EVAP and EGR Valve
OBD II Symbol Description Notice
ESD Notice

Circuit Description

The PCM tests the EVAP system for the following conditions:

•	Large and small leaks (P0440 and P0442)

•	Excess vacuum (P0446)

•	Purge flow during non-commanded conditions (P1441)

•	Fuel Pressure sensor and Fuel Level sensor faults (P0452, P0453, P0461, P0462 and P0463)

•	EVAP Purge and Vent Valve faults (P1645 and P1646)

The PCM monitors the amount of vacuum in the EVAP system by monitoring the Fuel Tank Pressure sensor. For this DTC the PCM turns ON both the EVAP Purge Valve and the EVAP Vent Valve when the Conditions for Running the DTC are met. This applies an engine vacuum to a closed EVAP system. This test checks whether a vacuum can develop in the EVAP system. Failure to develop a vacuum may result from a large leak or from a restriction. This DTC will set after two consecutive failures of the above test.

Conditions for Running the DTC

•	DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0135, P0141, P0151, P0152, P0153, P0154, P0452, P0453, P0503, P1111, P1112, P1114, P1115, P1133 or P1153 are not set.

•	Battery voltage is between 10.5 and 17.5 volts.

•	Barometric pressure is more than 71.78 kPa.

•	Fuel level is between 10% and 89.8% of full capacity for at least 3.2 seconds continuously. The time limit is required because fuel sloshing within the tank may cause the fuel level indication to vary outside the fuel level limits.

•	Coolant temperature is between 2°C and 32.7°C.

•	Intake air temperature is between 2°C and 32.7°C

•	Start up coolant and intake air temperature are within 14.2°C of each other.

Conditions for Setting the DTC

The EVAP system cannot develop vacuum.

Action Taken When the DTC Sets

•	The PCM will illuminate the Malfunction Indicator Lamp (MIL) after two consecutive drive trips that the diagnostic runs and fails.

•	The PCM will record operating conditions at the time the DTC sets. This information will be stored in the Freeze Frame and Failure Records.

•	A first failure of this DTC will store in Last Test Failed but not History.

Conditions for Clearing the MIL/DTC

•	The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

•	A Last Test Failed DTC will clear when the diagnostic runs and does not fail.

•	A History DTC will clear after forty consecutive warm-up cycles with no failures of any diagnostic test.

•	Use a scan tool to clear DTCs.

•	Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

Diagnostic Aids

Important: An accurate indication of fuel level is required for the PCM 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 as History.

Perform a physical inspection of the EVAP system. Check for the following conditions:

•	A loose, missing, defective, or incorrect fuel tank cap

•	Incorrectly routed or defective EVAP system vacuum and vapor lines

•	A malfunctioning or damaged EVAP vapor canister

Check for charcoal release from the EVAP vapor canister. Refer to the EVAP System Cleaning procedure.

The vacuum and pressure in the EVAP system is measured in inches of water (H2O). Most gauges measure vacuum in inches of mercury (Hg) and pressure in pounds per square inch (psi). The following shows how the values compare:

in H2O	in Hg	psi
1in H2O	0.07 in Hg	0.0361 psi
5 in H2O	0.36 in Hg	0.180 psi
10 in H2O	0.73 in Hg	0.361 psi
15 in H2O	1.10 in Hg	0.541 psi

Test Description

Inspect the service port. Make sure that the dust cap and valve core is not loose or damaged (the valve core may have left hand threads). If service port leakage is suspected 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/adaptor over the unthreaded end portion of the service port.

Apply vacuum to 5 in. Hg. If the vacuum does not hold replace the service port (may require line replacement).

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 off 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.

Refer to the information supplied with the EVAP pressure/purge diagnostic cart on proper setup and adjustment procedures.

If a leak was not found in Step 10 and the vehicle is equipped with On Board Refueling Vapor Recovery (Aurora or Seville) connect the EVAP pressure/purge Diagnostic station with the fuel cap adaptor (J 41415-40) to the fuel tank filler neck and repeat Step 10. These ORVR vehicles are equipped with a check valve at the base of the filler tube which may not allow pressure from the EVAP service port to be applied to the filler tube and the fuel cap.

With pressure applied it may be necessary to disconnect the EVAP lines at the components to verify that the line or component is not restricted.

An EVAP Pressure sensor that does not correctly respond to pressure (or vacuum) will cause this DTC to set.

The EVAP Pressure Sensor monitors a range from 7.5 in. H2O of pressure to -17.5 in. H2O of pressure (vacuum).

Step

Action

Value(s)

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to thePowertrain OBD System Check

Check for DTC's P0442, P0446, P0452, P0453, P0461, P0462, P0463, P1441, P1645 and P1646.

Are any of the above EVAP system DTC's stored in HISTORY?

Go to DTC's that are set.

Go to Step 3

Inspect the EVAP system for the following conditions:

•	A loose, incorrect, defective or missing fuel tank cap.

•	Improperly routed, kinked or damaged EVAP system purge lines.

•	A damaged EVAP system component.

•	A loose, missing or damaged service port dust cap and/or schrader valve. Refer to Test Descriptions.

Repair the EVAP system if needed.

Was a repair made to the EVAP system?

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 4

Important: Before proceeding with the Service Bay Test the vehicle must meet the following operating criteria:

•	Battery voltage between 10.5 and 15 volts.

•	Fuel level between 7 and 63 Litres.

•	Key ON engine temperature between 3.5°C and 35°C.

Perform the Service Bay Test for the EVAP system.

Does the vehicle pass the Service Bay Test?

Fault not present. Refer to Test Descriptions

Go to Step 5

Turn the ignition OFF.
Remove the vacuum source connection from the EVAP Purge Solenoid Valve.
Connect a vacuum gauge (in. Hg.) to the vacuum source (do not TEE gauge into lines).
Start and idle the engine.

Is the vacuum measured on the gauge the same or more than the value specified?

12 in. Hg.

Go to Step 6

Go to Step 12

Turn the ignition OFF.
Reconnect the vacuum source to the EVAP Purge Solenoid Valve.
Connect the vacuum gauge (in. Hg.) to the purge connection of the EVAP Purge Solenoid Valve.
Start and idle the engine.
Using a scan tool command the EVAP Purge Solenoid Valve to 100% purge.

Is the vacuum measured on the gauge the same or more than the value specified?

12 in. Hg.

Go to Step 7

Go to Step 13

Turn the ignition OFF.
Disconnect the fuel tank vapor and the EVAP purge line from the EVAP vapor canister.
Plug the canister fitting of the fuel tank vapor line.
Connect a hand vacuum pump to the EVAP Purge line canister fitting.
With the ignition ON, command the EVAP Vent Valve ON (closed) with a scan tool.
Using the hand vacuum pump apply vacuum up to the specified value.

Can the specified value of vacuum be obtained and held?

5 in. Hg.

Go to Step 10

Go to Step 8

Leave system connected as in Step 7.
Disconnect the vent line at the EVAP Vent Valve.
Plug the vent line.
Using the hand vacuum pump apply vacuum up to the specified value.

Can the specified value of vacuum be obtained and held?

5 in. Hg.

Go to Step 14

Go to Step 9

Inspect the EVAP Vent line from the canister to the EVAP Vent Valve for leaks.
Replace if needed.

Was the EVAP Vent line replaced?

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 15

Important: The following steps require the EVAP pressure/purge diagnostic station J 41413 and the ultrasonic leak detector J 41416.

Always zero the EVAP Pressure and Vacuum (in. H2O) gauges on the EVAP pressure/purge diagnostic station before proceeding with diagnosis.

Turn the ignition OFF.
Remove the plug and the hand vacuum pump.
Reconnect the EVAP vapor canister purge and tank vent lines.
Connect the EVAP pressure/purge diagnostic station J 41413 to the EVAP system service port.
Using a scan tool command the EVAP Vent Valve ON (closed).
Continuously attempt to pressurize the EVAP system by leaving the EVAP pressure/purge diagnostic station control knob in the pressurize position.
Using the ultrasonic leak detector J 41416 locate and repair EVAP system leak.

Was a leak found and repaired?

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 11

Check the EVAP system for restrictions. Refer to Test Descriptions.
Repair as needed.

Was a restriction found and repaired?

Go to Powertrain Control Module Diagnosis for Verify Repair

Go to Step 16

Repair the vacuum source to the EVAP Purge Solenoid Valve.

Is the repair complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Important: Inspect the EVAP Purge Solenoid Valve and the purge line for carbon contamination. Refer to Diagnostic Aids .

Replace the EVAP Purge Solenoid Valve.

Is the replacement complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Replace the EVAP Vent Valve.

Is the replacement complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Replace the EVAP Vapor Canister.

Is the replacement complete?

Go to Powertrain Control Module Diagnosis for Verify Repair

Relieve all system pressure.
Using the scan tool, use the Purge/Seal function to turn the EVAP Purge Solenoid Valve ON to varying vacuum levels with the engine running and quickly SEAL the system with the scan tool. Leaving the EVAP Purge Solenoid Valve ON for higher percents or longer times will allow a higher amount of vacuum to develop. A maximum of 14 in. H2O of vacuum can be applied to the EVAP system using the scan tool.
While the system is sealed compare the EVAP pressure/purge diagnostic stations vacuum gauge (in. H2O) to the vacuum shown on the scan tool from the EVAP Fuel Tank Pressure sensor. Allow a few seconds for the system to stabilize.

Do both values indicate the same amount of vacuum in the EVAP system to within the range specified?

+ or - 2 in. H2O

Go to Step 3

Go to Step 17

Replace the EVAP Pressure Sensor.

Is the replacement complete?

Go to Powertrain Control Module Diagnosis for Verify Repair