| Table 1: | DTC P0440 and P0442 |
Circuit Description
The powertrain control module (PCM) tests the evaporative emission (EVAP) system for the following conditions:
| • | Large and small leaks |
| • | Excess vacuum |
| • | Purge flow during non-commanded conditions |
| • | Fuel level and fuel pressure sensor faults |
| • | EVAP purge and vent valve faults |
The PCM monitors the fuel tank pressure (FTP) sensor in order to determine the level of vacuum/pressure in the EVAP system. The PCM commands both the EVAP purge solenoid and the EVAP vent valve ON when the Conditions for Running the diagnostic trouble code (DTC) are met in order to apply an engine vacuum to the EVAP system. The PCM commands the EVAP purge solenoid OFF once the system has reached a predetermined level of vacuum. The EVAP system should HOLD the vacuum in the sealed system. The PCM sets this DTC in order to indicate a small leak if the EVAP system fails to hold a predetermined level of vacuum for a predetermined length of time. This DTC sets after failing the above test twice.
Conditions for Running the DTC
| • | DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1111, P1112, P1114, P1115, P1121 or P1122 are not set. |
| • | The barometric pressure (BARO) is more than 75 kPa. |
| • | The fuel level is between 15-85 percent of full capacity. |
| • | The throttle position (TP) sensor angle less than 75 percent. |
| • | The vehicle speed less than 102 km/h (65 mph). |
| • | The engine coolant temperature (ECT) is between 4-30°C (39-86°F). |
| • | The intake air temperature (IAT) is between 4-30°C (39-86°F). |
| • | The start up engine coolant temperature and intake air temperature are within 9°C (16°F) of each other. |
Conditions for Setting the DTC
The vacuum in the EVAP system decays (leaks) at too fast a rate.
Important: This DTC does NOT report a first failed test. A first fail of this DTC will have a scan tool status as Not Run. Use the scan tool data display parameter of EVAP Test Result to determine if this DTC has failed or passed for this ignition cycle.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Important:
• Remove any debris from the PCM connector surfaces before servicing
the PCM. Inspect the PCM connector gaskets when diagnosing/replacing
the PCM. Ensure that the gaskets are installed correctly.
The gaskets prevent water intrusion into the PCM. • 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 DTC's diagnostic table. Always
inspect for fuel level sensor DTCs stored as History. • The Service Bay Test may have to be performed in cold ambient
air temperatures when the vehicle is running a winter grade fuel. The scan
tool displays a message when the service bay test does
not run. • Inspect for charcoal release from the vapor canister. Refer to
the
Evaporative Emission System Cleaning
procedure.
Conditions for Running the Service Bay Test
| • | The battery voltage is between 10.5-17.5 volts. |
| • | The fuel level is between 15-85 percent of the full capacity. |
| • | The engine temperature is between 3.5-35°C (38-95°F). |
Perform a physical inspection of the EVAP system. Inspect 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 vapor canister |
| • | Inspect for charcoal release from the vapor canister. Refer to the Evaporative Emission System Cleaning procedure. |
The vacuum and pressure in the EVAP system is measured in inches of H2O (water). Most gauges measure vacuum in inches of Hg (mercury) and pressure in psi (pounds per square inch). The following table illustrates how the values compare:
in H2O | in Hg. | psi |
|---|---|---|
1 in 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
The numbers below refer to the step numbers on the diagnostic table.
-
You may need to partially lower the fuel tank in order to inspect the upper portion of the tank and the EVAP line connections.
-
An intermittent leak or restriction is indicated if the vehicle passes the Service Bay Test. A fuel tank cap that is loose or off causes this DTC to set.
If the Service Bay Test cannot 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 and purge diagnostic cart on proper setup and adjustment procedures.
This step tests for a leak at the top of the fuel tank, at the fuel filler hose, and the fuel cap. Place the Ultrasonic Leak Detector in these areas.
-
Tests for restrictions in EVAP system.
-
A fuel tank pressure sensor that does not correctly respond to pressure, or vacuum, causes this DTC to set.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Emission Hose Routing Diagram and Engine Controls Schematics | ||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||
2 | Are any other EVAP system DTCs stored in history? | -- | Go to the applicable DTC table | |||||||||
Inspect the EVAP system for the following conditions:
Repair the EVAP system if needed. Did you find and repair the condition? | -- | Go to Step 21 | Go to Step 4 | |||||||||
|
Important: Ensure that the Conditions for Running the Service Bay test are met before proceeding with this diagnostic. Refer to Diagnostic Aids. Perform the EVAP system Service Bay Test using a scan tool. Does the EVAP diagnostic pass the Service Bay Test? | -- | Go to Diagnostic Aids | Go to Step 5 | |||||||||
5 |
Important: The DTCs must be cleared from the PCM in order to use the output control function on the scan tool. Can the value specified be obtained and held? | 10 in Hg | Go to Step 6 | Go to Step 15 | ||||||||
6 |
Important: If an audible solenoid click cannot be heard and DTC P0443 is not set, inspect the EVAP canister purge solenoid circuits for high resistance.
Is the vacuum measured on the gauge the same or more than the specified value? | 12 in Hg | Go to Step 8 | Go to Step 7 | ||||||||
7 |
Is the vacuum measured on the gauge the same or more than the specified value? | 12 in Hg | Go to Step 15 | Go to Step 14 | ||||||||
8 |
Can the specified value of vacuum be obtained and held? | 5 in Hg | Go to Step 9 | Go to Step 18 | ||||||||
9 |
Can the specified value of vacuum be obtained and held? | 5 in Hg | Go to Step 12 | Go to Step 10 | ||||||||
10 |
Can the specified value of vacuum be obtained and held? | 5 in Hg | Go to Step 16 | Go to Step 11 | ||||||||
11 |
Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 17 | ||||||||
|
Important: The following steps require theJ 41413 EVAP pressure and purge diagnostic station and the J 41416 ultrasonic leak detector. Always zero the EVAP pressure and vacuum (in H2O) gauges on the J 41413 EVAP pressure and purge diagnostic station before proceeding with diagnosis.
Did you find and repair the condition? | -- | Go to Step 21 | Go to Step 13 | |||||||||
Important: You may need to apply pressure in order to disconnect the EVAP lines at the components . A restriction would prevent a vacuum, or the step 10 test pressure, from forming in the fuel tank. Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 19 | |||||||||
14 | Repair the vacuum source to the EVAP purge solenoid valve. Is the action complete? | -- | Go to Step 21 | -- | ||||||||
15 |
Important: Inspect the EVAP purge solenoid valve and the purge line for carbon contamination. Refer to Diagnostic Aids . Replace the EVAP purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Is the action complete? | -- | Go to Step 21 | -- | ||||||||
16 | Replace the EVAP vent valve. Refer to Evaporative Emission Canister Vent Solenoid Valve Replacement . Is the action complete? | -- | Go to Step 21 | -- | ||||||||
17 | Replace the EVAP vapor canister. Refer to Evaporative Emission Canister Replacement . Is the action complete? | -- | Go to Step 21 | -- | ||||||||
18 | Repair the EVAP line from the EVAP purge solenoid valve to the EVAP canister as necessary. Is the action complete? | -- | Go to Step 21 | -- | ||||||||
Important: The fuel tank pressure sensor range is from +7.5 in. H2O of pressure to -17.5 in. H2O of pressure, or vacuum. In order to test the fuel tank pressure sensor for vacuum response, command the EVAP purge solenoid valve ON with the engine running and quickly SEAL the system. Leaving the EVAP purge solenoid valve ON for a longer period of time allows a greater level of vacuum to develop. Does the fuel tank pressure sensor indicate the actual amount of pressure in the EVAP system? | -- | Go to Step 3 | Go to Step 20 | |||||||||
20 | Replace the fuel tank pressure sensor. Refer to Fuel Tank Pressure Sensor Replacement . Is the action complete? | -- | Go to Step 21 | -- | ||||||||
21 |
Does the DTC run and pass? | -- | Go to Step 22 | Go to Step 2 | ||||||||
22 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||
