Diagnostic Instructions
DTC Descriptor
DTC P0455: Evaporative Emission (EVAP) System Large Leak
Circuit/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 solenoid valve OPEN and the EVAP vent solenoid 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 solenoid valve closed,
sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. 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 solenoid
valves.
Control Module Command
| EVAP Canister Purge Solenoid Valve
| EVAP Canister Vent Solenoid Valve
|
ON
| Open
| Closed/Not Venting
|
OFF
| Closed
| Open/Venting
|
Conditions for Running the DTC
| • | DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0222, P0223, P0452, P0453, P0502, P0601, P0602, P0606, P0641 are not set. |
| • | The ignition voltage is between 11-18 volts. |
| • | The barometric pressure (BARO) is more than 74 kPa. |
| • | The fuel level is between 15-85 percent. |
| • | The start-up engine coolant temperature (ECT) is between 4-30°C (39-86°F). |
| • | The start-up intake air temperature (IAT) is between 4-30°C (39-86°F). |
| • | The start-up ECT and IAT are within 8°C (14.4°F) of each other. |
| • | DTC P0455 runs once per cold start within 10 minutes of start-up. |
Conditions for Setting the DTC
The EVAP system is not able to achieve or maintain vacuum for up to 4 times during the diagnostic test.
Action Taken When the DTC Sets
DTC P0455 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P0455 is a Type B DTC.
Diagnostic Aids
| • | A loose, missing, incorrect, or damaged fuel fill cap may cause this DTC to set. |
| • | To help locate intermittent leaks, use the
J 41413-200
to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the
J 41413-SPT
. Introducing smoke in 15-second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner. |
| • | To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the
J 41413-SPT
. |
| • | Reviewing the 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. |
| • | A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool Purge/Seal function to create a vacuum, seal the system and observe the FTP parameter for the vacuum decay, this type of leak may be
detected. |
| • | If a small leak is difficult to find, it may be necessary to remove the EVAP components and leak test them one at a time. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Special Tools Required
| • | J 41413-200
Evaporative Emission System Tester (EEST) |
| • | CH-48096
EVAP Service Access Port Tool |
Circuit/System Testing
Important:
| • | Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. |
| • | Refer to the
J 41413-200
operation manual for detailed instructions. |
- Using the
GE-41415-50
, connect the
J 41413-200
to the vehicle filler neck.
- Seal the system and use the flow meter on the
J 41413-200
, calibrated to 0.51 mm (0.02 in) to determine that there is no leak in the EVAP system.
| ⇒ | If a leak is detected, use the
J 41413-200
to apply smoke to the EVAP system at the service port or the filler neck until the leak is located. For vehicles without a service port, disconnect the
purge tube at the quick connector on the EVAP canister side of the purge solenoid valve and install the
CH-48096
. |
- Start the engine with the
J 41413-200
connected to the fuel filler neck.
- Allow the engine to idle.
- Use the Purge/Seal function to seal the system with a scan tool.
- Command the EVAP canister purge solenoid valve to 20 percent.
- The vacuum/pressure gage on the
J 41413-200
and the FTP parameter on the scan tool should both show vacuum.
| ⇒ | If the vacuum/pressure gage shows vacuum but the FTP parameter does not show vacuum, replace the FTP sensor. |
| ⇒ | If neither the FTP parameter nor the vacuum/pressure gage shows vacuum, repair the restriction in the purge path. |
- Verify that the vacuum increases to the abort limit on the scan tool or more than 3.2 volts, and the value is closely similar between the scan tool and the vacuum/pressure gage on the
J 41413-200
.
| ⇒ | If the values are not similar or the voltage did not reach 3.2 volts, replace the FTP sensor. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
