DTC P0455 or P0497 (LAU or LBW)

 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 Descriptors

 DTC P0455

Evaporative Emission (EVAP) System Large Leak Detected

 DTC P0497

Evaporative Emission (EVAP) System No Flow During Purge

 Circuit/System Description

The control module tests the evaporative emission (EVAP) system for a large leak, or a stuck closed EVAP canister purge valve. 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 closes the EVAP canister purge valve which seals the system. At the same time the control monitors the FTP sensor input in order to determine the EVAP system's vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level increases too slowly, a DTC sets.

 

FTP Sensor Signal Voltage Fuel Tank Pressure
High, Approximately 1.5 Volts or More

 Negative Pressure/Vacuum
Low, Approximately 1.5 Volts 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, 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 greater than 10 minutes or the fuel trim is stable.
• The FTP 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 operating at idle.
• The barometric pressure (BARO) is greater than 68 kPa.
• The fuel level is between 11-88 percent.

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


  Action Taken When the DTC Sets

DTC P0455, DTC P0497 is a Type A/B DTC.

 Conditions for Clearing the DTC

DTC P0455, DTC P0497 is a Type A/B DTC.

 Diagnostic Aids


• A loose, missing, or damaged fuel fill cap can cause this DTC to set.
• A stuck closed, blocked, or restricted EVAP canister purge solenoid valve, can cause this DTC to set.
• A blockage or restriction in the EVAP canister purge solenoid valve vacuum supply hose, EVAP canister purge solenoid valve purge pipe, EVAP canister, or vapor pipe, can cause this DTC to set.
• A temporary blockage in the EVAP canister purge solenoid valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
• To help locate intermittent leaks, use the J 41413-200EEST to introduce smoke into the EVAP system. Manipulate all the EVAP system's components while the smoke is checked with J 41413-SPT White Light. Blowing in smoke at 15 second intervals builds up less pressure in 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-SPTWhite Light.

• Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.


 Reference Information

 Schematic Reference

Engine Controls Schematics

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


• J 41413-SPTHigh Intensity White Light

• J 41413-VLVEVAP Port Vent Fitting Tool

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

• J 41413-300EVAP Cap and Plug Kit

• CH 48096EVAP Service Port Access Tool

• J 41415-30Fuel Tank Adapter

• For equivalent regional tools, refer to Special Tools.
 Circuit/System Verification


1. Verify the following conditions do not exist in the EVAP system:

• Loose, incorrect, missing, or damaged fuel fill cap
• Loose, missing, or damaged service port schrader valve, if equipped
• A damaged Q12 EVAP canister purge solenoid valve
• Disconnected, incorrectly routed, kinked, or damaged EVAP pipes and hoses
• A damaged Q13 EVAP vent solenoid valve or EVAP canister
• If you find any of the above conditions, repair as necessary.
2.
Note

Refer to the J 41413-200Evaporative Emissions System Tester (EEST) operation manual for detailed instructions.


Remove the fuel fill cap. Connect the J 41415-30Fuel Tank Adapter to the fuel tank filler neck. Connect the J 41413-200EEST to the J 41415-30 Fuel Tank Adapter.
3. Calibrate the J 41413-200EEST Flow Meter to the correct leak orifice for the vehicle.

4. Command the EVAP vent solenoid valve closed with a scan tool.

5.
Note

Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.


 Activate the J 41413-200EEST and compare the flow meter's stable floating indicator position to the red flag. The floating indicator should be level with the red flag.
6. If the floating indicator is above the red flag, test for a leak in the EVAP system.
7. If the floating indicator is below the red flag, test for a blockage or restriction in the EVAP system.
8. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.


 Circuit/System Testing


Leak Testing

1.
Note
• You must start with the Circuit/System Verification before proceeding with Circuit/System Testing.

• Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. The system flow will be less with higher temperatures.


 Connect the J 41415-30Fuel Tank Adapter to the fuel tank filler neck. Connect the J 41413-200EEST to the J 41415-30 Fuel Tank Adapter.
2. Connect the CH-48096Access Tool between the Q12 EVAP purge solenoid valve and the EVAP purge pipe.

3. Turn the nitrogen/smoke valve on the control panel to SMOKE.
4. Command the Q13 EVAP vent solenoid valve closed with a scan tool.

5. Use the remote switch to introduce smoke into the EVAP system.
6. Use the J 41413-VLVFitting Tool to open the EVAP service port. Once smoke is observed, remove the J 41413-VLV Fitting Tool.
7.
Note

Introduce smoke at 15 second intervals while testing the system.


 Verify that smoke is not exiting the entire EVAP system with the J 41413-SPTWhite Light.
8.
Note

The fuel tank may need to be lowered to improve visibility of some of the EVAP system components.


 If smoke is observed, repair the condition as necessary.
9. Remove the J 41415-30Fuel Tank Adapter from the filler neck.
10. Install the fuel fill cap.

11. Connect the J 41413-200 EEST nitrogen/smoke supply hose to the EVAP service port of the CH-48096Access Tool.

12. Command the Q13 EVAP vent solenoid valve closed with a scan tool.

13. Use the remote switch to introduce smoke into the EVAP system.
14.
Note

The fuel tank may need to be lowered to improve visibility of some of the EVAP system components.


 Verify that smoke is not exiting the entire EVAP system with the J 41413-SPTWhite Light.
15. If smoke is observed, repair the condition as necessary.
16. Verify individual EVAP system components do not leak using the J 41413-300Kit.
17. If a condition is found replace the affected component.

Blockage/Restriction Testing

1. Connect the J 41415-30Fuel Tank Adapter to the fuel tank filler neck. Connect the J 41413-200EEST to the J 41415-30 Fuel Tank Adapter.
2. Seal the EVAP system using the scan tool EVAP Purge/Seal function.

3. Pressurize the EVAP system with nitrogen to 9.33 mm/Hg (5 in/H2O). Compare the scan tool Fuel Tank Pressure Sensor parameter to the J 41413-200EEST pressure/vacuum gauge. Verify the scan tool FTP sensor parameter is within +/-0.9 mmHg (+/-0.5 in.H2O) of the pressure/vacuum gauge.
4. If not within the specified range, replace the B150 FTP sensor.
5. Command the Q12 EVAP purge solenoid valve to 100 percent with a scan tool. Verify the scan tool FTP sensor parameter is -0.9 to +0.9 mmHg (-0.5 to +0.5 in.H2O).
6. If greater than the specified value, disconnect the EVAP pipes listed below one at a time while observing the scan tool FTP sensor parameter. If the FTP sensor parameter drops to within the specified range when a pipe is disconnected, repair the blockage or restriction in one of the following EVAP pipe/hoses:
• EVAP purge vacuum source from the Q12 EVAP purge solenoid valve
• EVAP purge pipe from the Q12 EVAP purge solenoid valve
• EVAP purge pipe at the EVAP canister
• EVAP vapor pipe at the EVAP canister
7. If a condition with the EVAP system cannot be located, refer to Diagnostic Aids for additional information.
 Component Testing


1. Seal the EVAP system using the scan tool EVAP Purge/Seal function.

2. Pressurize the EVAP system to 9.33 mm/Hg (5 in/H2O).
3. Compare the scan tool Fuel Tank Pressure Sensor parameter to the J 41413-200EEST pressure/vacuum gauge. Verify the scan tool FTP sensor parameter is within +/-0.9 mmHg (+/-0.5 in.H2O) of the pressure/vacuum gauge.
4. If not within the specified range, replace the B150 FTP sensor.
5. Command the Q13 EVAP vent solenoid valve open with a scan tool. Verify the scan tool FTP sensor parameter is -0.9 to +0.9 mmHg (-0.5 to +0.5 in.H2O).
6. If not within the specified range, replace the B150 FTP sensor.
 Repair Instructions


• Fuel Pressure Sensor Replacement

• Evaporative Emission Canister Purge Solenoid Valve Replacement

• Evaporative Emission Canister Vent Solenoid Valve Replacement

• Evaporative Emission Canister Replacement


 Repair Verification


1. Turn the nitrogen/smoke valve to nitrogen.
2. Command the Q13 EVAP vent solenoid valve closed with a scan tool.
3. Use the remote switch to activate the J 41413-200EEST.
4. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating indicator stabilizes.

5. Verify the flow meter's stable floating indicator position is at or below the red flag.

6. Remove the CH-48096Access Tool , and connect the purge hose/pipe to the EVAP purge solenoid valve.
7. Clear the DTCs with a scan tool.