GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 G6 🢒 Engine 🢒 Engine Controls and Fuel - 3.9L 🢒 DTC P0455

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

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.

Conditions for Running the DTC
    • DTCs P0068, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0128, P0442, P0443, P0446, P0449, P0452, P0453, P0502, P0503, P0606, P0641, P0651, P1516, P1548, P2101, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2176 are not set.
    • The engine is running.
    • The ignition voltage is between 10-18 volts.
    • The barometric pressure (BARO) is more than 70 kPa.
    • The fuel level is between 15-90 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 9°C (16°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 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. 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 .

Reference Information

Schematic Reference

    •  Evaporative Emissions Hose Routing Diagram
    •  Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

    • CH-48096 EVAP Service Access Port Tool
    • GE-41415-50 Fuel Tank Cap Adapter
    • J 41413-200 (J 41413-100) Evaporative Emission System Tester (EEST)
    • J 41413-300 EVAP Cap and Plug Kit
    • J 41413-311 EVAP Plug
    • J 41413-VLV EVAP Service Port Vent Fitting
    • J 41413-SPT High Intensity White Light

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.

  1. Connect the J 41413-200 to the vehicle EVAP service port. 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 .
  2. Seal the EVAP 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.
    3. ⇒If a leak is detected, use the J 41413-200 to apply smoke to the EVAP system at the service port until the leak is located.
  3. To test for a restriction, connect the J 41413-200 nitrogen/smoke hose to the J 41413-311 brass cone adapter. Disconnect the hose at the fuel cap end of the GE-41415-50 . Connect the J 41413-311 to the disconnected hose on the GE-41415-50 . Install the GE-41415-50 filler neck end only to the vehicle.
  4. Allow the engine to idle.
  5. Use the Purge/Seal function to seal the system with a scan tool.
  6. Command the EVAP canister purge solenoid valve to 30 percent.
  7. The vacuum/pressure gage on the J 41413-200 and the FTP parameter on the scan tool should both show vacuum.
    8. ⇒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.
  8. 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 .
    9. ⇒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.

    •  Fuel Tank Pressure Sensor Replacement
    •  Control Module References for engine control module (ECM) replacement, setup, and programming