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DTC P0455 or P0497 (LAU)

DTC P0455 or P0497 (LAU)

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

DTC P0497

Evaporative Emission (EVAP) System No Flow During Purge

Circuit/System Description

The 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 have been met the ECM commands the evaporative emission canister vent solenoid valve ON and the evaporative emission canister purge solenoid valve ON, allowing vacuum into the evaporative emission 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.


Fuel Tank Pressure Sensor Signal Voltage Fuel Tank Pressure
High, Approximately 1.5 V or More Negative Pressure/Vacuum
Low, Approximately 1.5 V or Less Positive Pressure


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


• Before the engine control module (ECM) can report DTC P0455 or DTC P0497 failed, DTCs P0446 and P0496 must run and pass.

• DTC P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, P0443, P0446, P0449, P0450, P0451, P0452, P0453, P0458, P0459, P0496, P0498, P0499, P0502, P0503, P0560, P0562, P0563, P0700, P2122, P2123, P2127, P2128, P2138, P2227, P2228, or P2229 is not set.

• The ignition voltage is between 10-18 V.

• The engine run time is longer than 10 min or the fuel trim is stable.

• The fuel tank pressure is between -18.7 and +9.8 mm Hg (-10.0 and +5.2 in. H2O).

• The Closed Loop fuel control is enabled.

• The engine is idling.

• The barometric pressure (BARO) is greater than 68 kPa.

• The fuel level is between 11-88 %.

• The ambient air temperature (IAT) is between 2-32°C (36-90°F).

• The engine coolant temperature (ECT) is within 10°C (18°F) of the ambient air temperature at engine start.

• The vehicle speed sensor (VSS) is less than 3 km/h (2 mph).

• The above conditions are met for greater than 30 s

• DTC P0455 or DTC P0497 will attempt to run up to 10 times or until the test completes successfully once per ignition cycle.


Conditions for Setting the DTC


• The ECM detects the EVAP system is not able to achieve or maintain vacuum during the diagnostic test. This condition can be the result of a large leak or a restriction in the EVAP system.

• The condition exists for greater than 4 s or for a cumulative of 30 s.


Action Taken When the DTC Sets

DTCs P0455 and P0497 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0455 and P0497 are Type B DTCs.

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 evaporative emission purge solenoid valve, purge pipe, evaporative emission canister, or vapor pipe, can cause this DTC to set.

• The evaporative emission system can be filled with smoke more quickly and completely by opening the system opposite the end where the smoke is injected. Close the system once smoke is observed.

• To help locate intermittent leaks using the J 41413-200 EEST, move all evaporative emission components while observing smoke with the J 41413-SPT White Light.

• Individual components can be isolated and tested using adapters in the J 41413-300 Kit.

• A condition may exist where a leak in the evaporative emission 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 evaporative emission system and then observe the fuel tank pressure parameter for vacuum decay.


Reference Information

Schematic Reference

Engine Controls Schematics (3.0L (LF1)) Engine Controls Schematics (2.8L (LAU))

Connector End View Reference

Component Connector End Views

Description and Operation

Evaporative Emission Control System Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools


• CH 48096 Evaporative Emissions Service Access Port Tool

• CH 41415-50 Fuel Tank Adapter

• J 41413-200 Evaporative Emissions System Tester (EEST)

• J 41413-300 Evaporative Emissions Cap and Plug Kit

• J 41413-311 Evaporative Emissions Plug

• J 41413-SPT High Intensity White Light

• J 41413-VLV Evaporative Emissions Service Port Vent Tool

• For equivalent regional tools, refer to Special 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.

• Refer to the J 41413-200 EEST operation manual for detailed instructions in Evaporative Emission System Diagnosis .



1. Disconnect the purge tube at the quick connector on the evaporative emission canister side of the Q12 evaporative emission canister purge solenoid valve. Install the CH 48096 Service Access Port Tool between the disconnected purge tube and the purge solenoid valve. Connect the J 41413-200 EEST to the service access port tool.

2. Use a scan tool to seal the evaporative emission system.

3. Use the flow meter on the J 41413-200 EEST , calibrated to 0.51 millimeter (0.020 inch) to determine that there is no leak in the evaporative emission system.

4. If a leak is detected, use the J 41413-200 EEST to apply smoke to the evaporative emission system at the purge tube until the leak is located using the J 41413-SPT White Light.

5. To test for a restriction, connect the J 41413-200 EEST nitrogen/smoke hose to the to the J 41413-311 Evaporative Emission Plug brass cone adapter. Disconnect the hose at the fuel cap end of the CH 41415-50 Adapter. Connect the J 41413-311 Evaporative Emission Plug to the disconnected hose on the GH 41415-50 Adapter. Install the CH 41415-50 Adapter filler neck end only to the vehicle.

6. Allow the engine to idle.

7. Use the Purge/Seal function to seal the system with a scan tool.

8. Command the EVAP Purge Solenoid Valve to 30 percent.

9. The vacuum/pressure gauge on the J 41413-200 EEST and the fuel tank pressure parameter on the scan tool should both show vacuum.

10. If the vacuum/pressure gauge shows vacuum, but the fuel tank pressure parameter does not show vacuum, replace the fuel tank pressure sensor.

11. If neither the fuel tank pressure parameter nor the vacuum/pressure gauge shows vacuum, repair the restriction in the purge path.

12. Verify that the vacuum increases to the abort limit on the scan tool or more than 3.2 V, and the values are similar between the scan tool and the vacuum/pressure gauge on the J 41413-200 EEST.

13. If the values are not similar, or the voltage did not reach 3.2 V, replace the B150 fuel tank pressure sensor.


Repair Instructions


• Fuel Tank Pressure Sensor Replacement

• Evaporative Emission Canister Purge Solenoid Valve Replacement (LAU) Evaporative Emission Canister Purge Solenoid Valve Replacement (LF1)

• Evaporative Emission Canister Vent Solenoid Valve Replacement (NT7, NU5)

• Evaporative Emission Canister Replacement (NT7, NU5)


Repair Verification


1. Seal the evaporative emission system and use the flow meter on the J 41413-200 EEST , calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the evaporative emission system.

2. Clear DTCs.