| Table 1: | DTC P0440 |
System Description
The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge valve OPEN and the EVAP vent valve CLOSED . This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent valves.
Control Module Command | EVAP Canister Purge Valve | EVAP Canister Vent Valve |
|---|---|---|
ON | Open | Closed |
OFF | Closed | Open |
Conditions for Running the DTC
| • | DTCs P0107, P0108, P0110, P0112, P0113, P0115, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121, or P1122 are not set. |
| • | The system voltage is between 10-18 volts. |
| • | The engine coolant temperature (ECT) is between than 4-30°C (39-86°F). |
| • | The intake air temperature (IAT) is between than 4-30°C (39-86°F). |
| • | The fuel tank level is between 15-85 percent. |
| • | The barometric pressure (BARO) is more than 75 kPa. |
| • | The vehicle speed sensor (VSS) is less than 121 km/h (75 mph). |
| • | The start-up ECT and IAT are within 9°C (16°F). |
Conditions For Setting the DTC
The EVAP system is not able to achieve or maintain a vacuum during the diagnostic test.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the 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
| • | Use the J 41413 EVAP Pressure and Purge Station in order to pressurize the EVAP system. Move all EVAP components while testing with the J 41416 Ultrasonic Leak Detector. |
| • | A temporary blockage in the EVAP canister purge valve, the purge pipe, or the EVAP canister could cause an intermittent condition. To repair a blockage in the EVAP system refer to Evaporative Emission System Cleaning . |
| • | Reviewing the Freeze Frame/Failure 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.
-
This step is used to verify if a leak is present.
-
This step verifies proper operation of the fuel tank pressure (FTP) sensor.
-
This step tests the EVAP canister purge valve for a restriction or blockage.
Step | Action | Values | Yes | No | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Evaporative Emissions Hose Routing Diagram | ||||||||||||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||||||||||||||
2 | Does the scan tool indicate DTC P0443 or DTC P0449 are also set? | -- | Go to Step 3 | |||||||||||||||||||||
3 |
Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 4 | ||||||||||||||||||||
Does the scan tool indicate that the Service Bay Test passed? | -- | Go to Diagnostic Aids | Go to Step 5 | |||||||||||||||||||||
5 |
Important: Always zero the EVAP pressure and vacuum (in H2O) gages on the J 41413 EVAP Pressure and Purge Station before proceeding with diagnosis.
Did you obtain and hold the specified value? | 5 in H2O | Go to Step 6 | Go to Step 8 | ||||||||||||||||||||
Compare the J 41413 value to the scan tool fuel tank pressure (FTP) sensor value. Does the J 41413 value measure near the scan tool value? | -- | Go to Step 7 | Go to Step 12 | |||||||||||||||||||||
7 |
Does the EVAP system pressure decrease? | -- | Go to Step 9 | Go to Step 10 | ||||||||||||||||||||
8 |
Important: It may be necessary to partially lower the fuel tank to inspect components located in the upper portion of the tank.
Did you locate and repair a leak? | -- | Go to Step 18 | Go to Diagnostic Aids | ||||||||||||||||||||
9 |
Does the vacuum gage show an increase in vacuum? | -- | Go to Diagnostic Aids | Go to Step 15 | ||||||||||||||||||||
10 |
Does the EVAP system pressure decrease? | -- | Go to Step 16 | Go to Step 11 | ||||||||||||||||||||
11 |
Does the EVAP system pressure decrease? | -- | Go to Step 17 | Go to Step 14 | ||||||||||||||||||||
12 | Monitor the fuel tank pressure (FTP) sensor voltage with a scan tool. Is the FTP sensor voltage more than the specified value? | 4.3 V | Go to DTC P0453 | Go to Step 13 | ||||||||||||||||||||
13 | Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- | ||||||||||||||||||||
14 | Repair for a pinched or obstructed EVAP vapor pipe. Did you complete the repair? | -- | Go to Step 18 | -- | ||||||||||||||||||||
15 | Replace the EVAP canister purge valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- | ||||||||||||||||||||
16 | Repair the restriction in the EVAP purge pipe. Refer to Evaporative Emission System Cleaning . Did you complete the repair? | -- | Go to Step 18 | -- | ||||||||||||||||||||
17 | Replace the EVAP canister. Refer to Evaporative Emission Canister Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- | ||||||||||||||||||||
18 |
Does the scan tool indicate that the Service Bay Test passed? | -- | Go to Step 19 | Go to Step 5 | ||||||||||||||||||||
19 | Observe the stored information in Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |||||||||||||||||||||
