Buick Regal: 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 Detected

Circuit/System Description

The engine control module (ECM) tests the evaporative emission (EVAP) system for a large leak or restrictions to the purge path in the EVAP system. When the enabling criteria has been met, the ECM commands the EVAP vent solenoid valve and purge solenoid valve ON, allowing vacuum into the EVAP system. The ECM monitors the fuel tank pressure sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time.

Conditions for Running the DTC

• DTCs P00C8, P00C9, P010C, P010D, P16A0, P16A1, P16A2, P160E, P160D, P16F3, P0068, P0101, P0102, P0103, P0111, P0112, P0113, P0114 P0116, P0117, P0118, P0122, P0123, P0125, P0128, P0191, P0192, P0193, P0222, P0223, P0443, P0449, P0452, P0453, P0454, P0502, P0503, P0601, P0604, P0606, P0722, P0723, P1104, P1682, P2100, P2101, P2102, P2103, P2135, P2176, P2227, P2228, P2229, P2230 are not set.
• The ignition voltage is between 11 - 32 V.
• The barometric pressure (BARO) is greater than 70 kPa.
• The fuel level is between 10 - 90%.
• The cold startup engine coolant temperature (ECT) and the startup intake air temperature (IAT) are within 8ºC (14ºF).
• The startup engine coolant temperature (ECT) is less than 35ºC (95ºF).
• The startup intake air temperature (IAT) is between 4 - 34ºC (39 - 93ºF).
• DTC P0455 runs once per cold start, shortly after purge is enabled followed by vent system performance test P0446.

Conditions for Setting the DTC

• The EVAP system is not able to achieve or maintain a calibrated level of vacuum before a calibrated amount of purge volume has passed through the system.
• After setting the DTC for the first time, 2 L (0.5 gal) of fuel must be consumed before setting the DTC for the second time.
• With a DTC P0455 detected a weak vacuum follow-up test (fuel cap replacement test) will run and pass if tank vacuum is greater than 2.74 kPa (11 in H2O). This test will run for a maximum of 21 min. This test runs until it passes.

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

• Inspect for a loose, missing, damaged, or incorrect fuel fill cap.
• Inspect for a damaged fuel filler neck seal surface.
• A blockage or restriction in the EVAP purge solenoid valve, purge pipe, EVAP canister, or vapor pipe, can cause this DTC to set.
• The EVAP system can be filled with smoke more quickly and completely by opening the system opposite the end where the smoke is injected. For example, when injecting smoke at the service port remove the fuel fill cap, or temporarily leave the vent open, until smoke is observed, then close the system and continue testing. If using a fuel cap adapter at the filler neck, use the J- 41413-VLV at the service port to allow the system to fill faster.
• To help locate intermittent leaks using the GE-41413-A move all EVAP components while observing smoke with the GE-41413-SPT.
• Individual components can be isolated and tested using adapters in the J-41413-300.
• When servicing the EVAP system, test pressure must not exceed 13 in H20 (0.5 PSI) as pressure in excess of this could cause system components to perform inaccurately.
• A condition may exist where a leak in the EVAP system only exists under a vacuum condition.
• This type of leak may be detected by using the scan tool Purge/Seal function to create a vacuum in the EVAP system and then observe the Fuel Tank Pressure Sensor parameter for vacuum decay.

Reference Information

Schematic Reference

Engine Controls Wiring Schematics (LTG)

Connector End View Reference

Component Connector End View Index

Powertrain Component View

Powertrain Component Views

Description and Operation

Evaporative Emission Control System Description

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• 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-41413-A Evaporative Emissions System Tester
• GE-41413-SPT High Intensity White Light
• GE-41415-30 Fuel Tank Cap Adapter
• GE-41415-60 Engine Induction System Leak Test Adapter/Capless Fuel Fill Adapter
• J-41413-300 EVAP Cap and Plug Kit
• J-41413-311 EVAP Plug (Brass Nozzle)
• J-41413-VLV EVAP Service Port Vent Fitting

For equivalent regional tools, refer to Special Tools (Diagnostic Tools) and Special Tools (Mechanical Tools)

Circuit/System Testing

NOTE:

• Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize or produce smoke from a leak.
• Refer to the GE-41413-A detailed instructions in Evaporative Emission System Diagnosis.

1. Disconnect the purge tube at the quick connector on the EVAP canister side of the purge solenoid valve and install the CH-48096.

2. Connect the GE-41413-A to the vehicle EVAP service port adapter.

3. Ignition ON, command the EVAP Purge/Seal function to Not Venting or System Seal with a scan tool to seal the EVAP system.

4. Verify that there is no leak in the EVAP system using the flow meter on the GE-41413-A , calibrated to 0.51 mm (0.020 in).

• If a leak is detected

1. Apply smoke to the EVAP system at the service access port adapter with the GE-41413-A.
2. Locate the leak using the GE-41413-SPT.
   • When the leak is located, repair or replace the affected component as necessary.

• Go to next step: If no leak detected

NOTE: The steps below test for a restriction in the purge path.

5. Connect the GE-41413-A nitrogen/smoke hose to the J-41413-311 or GE-41415-60 for capless vehicles.

6. Disconnect the hose at the fuel cap end of the GE-41415-30 and connect to the J-41413-311.

7. Install the GE-41415-30 or GE-41415-60 , filler neck end only, to the vehicle.

8. Engine idling, command the Purge/Seal function to Not Venting or System Seal with a scan tool to seal the system.

NOTE: The scan tool will abort purge when a predetermined value is reached. This is to prevent damage to the fuel tank.

9. Command the EVAP Purge Solenoid Valve to 10-30% with a scan tool.

10. Verify the vacuum/pressure gauge on the GE-41413-A and the scan tool Fuel Tank Pressure Sensor parameter both show vacuum.

• If the vacuum/pressure gauge shows vacuum but the Fuel Tank Pressure Sensor parameter does not show vacuum

Replace the B150 Fuel Tank Pressure Sensor.

• If both do not show vacuum

Repair the restriction in the purge path.

• Go to next step: If both show vacuum

11. Verify that the Fuel Tank Pressure Sensor parameter increases to greater than 3.2 V, and the pressure values are similar between the scan tool Fuel Tank Pressure Sensor and the vacuum/pressure gauge on the GE-41413-A.

• If not within the specified range

Replace the B150 Fuel Tank Pressure Sensor.

• Go to next step: If within the specified range

12. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Fuel Tank Pressure Sensor Replacement (FWD) or Fuel Tank Pressure Sensor Replacement (AWD)
• Control Module References for control module replacement, programming and setup.

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