• Perform the Diagnostic System Check prior to using this diagnostic procedure:Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis:Strategy Based Diagnosis
• An overview of each diagnostic category can be found here:Diagnostic Procedure Instructions

For an overview of the component/system, refer to:Evaporative Emission Control System Description

This diagnostic tests the Evaporative Emission (EVAP) System for a small leak when the ignition is off and the Conditions for Running the DTC are met. When the ignition is turned off and the EVAP system is sealed, a change in the fuel tank vapor temperature occurs which results in a corresponding pressure change in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure (FTP) sensor. With a leak in the system, the amount of pressure change will be less than that of a sealed system.

This diagnostic tests the Evaporative Emission (EVAP) System for a large leak or restrictions to the purge path in the EVAP system. When the Conditions for Running the DTC are met the control module commands the EVAP canister vent solenoid valve and EVAP purge solenoid valve on, allowing vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum before a calibrated amount of purge volume has passed through the system.

• DTCs related to the following system/component = Not Set
• B9 Ambient Air Temperature Sensor
• B34 Engine Coolant Temperature Sensor
• B46 Fuel Level Sensor
• B66 Intake Air Temperature Sensor
• B75B Mass Air Flow/Intake Air Temperature Sensor
• B115 Vehicle Speed Sensor
• B150 Fuel Tank Pressure Sensor
• Q12 Evaporative Emission Purge Solenoid Valve
• Q13 Evaporative Emission Vent Solenoid Valve
• Evaporative Emission (EVAP) Purge System
• Fuel Pump
• Ignition Off Time
• Output Speed Sensor
• Ambient Air Temperature Sensor=0 to 34°C (32 to 93°F)
• Barometric Pressure Sensor=Greater than 70 kPa (10.1 PSI)
• Engine Coolant Temperature Sensor=Greater than 63°C (145°F)
• Engine Run Time=Greater than 10 min—Before ignition off
• Fuel Level Sensor=10 to 90%
• Ignition=Off
• Start-Up Engine Coolant Temperature Sensor&Start-Up Intake Air Temperature Sensor=Within 8°C (14°F) of each other
• Time since diagnostic ran lastGreater than 8 h=Test PassedorGreater than 8 h=Test Failed
• Vehicle Distance Traveled During Drive Cycle=Greater than 16.0 km (10.0 mi)—Before ignition off

Frequency the DTC runs=Once—Per hot soak@Ignition Off—DTC test could take 40 min to complete

• DTCs related to the following system/component = Not Set
• B9 Ambient Air Temperature Sensor
• B34 Engine Coolant Temperature Sensor
• B46 Fuel Level Sensor
• B66 Intake Air Temperature Sensor
• B74 Manifold Absolute Pressure Sensor
• B75B Mass Air Flow/Intake Air Temperature Sensor
• B115 Vehicle Speed Sensor
• B150 Fuel Tank Pressure Sensor
• Q12 Evaporative Emission Purge Solenoid Valve
• Q13 Evaporative Emission Vent Solenoid Valve
• Q38 Throttle Body
• Evaporative Emission (EVAP) Purge System
• Fuel Pump
• Ignition Off Time
• Output Speed Sensor
• Reduced Engine Power
• Throttle Position Sensor
• Q12 Evaporative Emission Purge Solenoid Valve—Flow=Greater than 2.0%
• Barometric Pressure Sensor=Greater than 70 kPa (10.1 PSI)
• Fuel Level Sensor=10 to 90%
• Ignition Voltage=Greater than 10.0 V
• Start-Up Engine Coolant Temperature Sensor&Start-Up Intake Air Temperature Sensor=Within 8°C (14°F) of each other
• Start-Up Engine Coolant Temperature Sensor=Less than 35°C (95°F)
• Start-Up Intake Air Temperature Sensor=4 to 35°C (39 to 95°F)

Frequency the DTC runs=Once—Per cold start-up

Evaporative Emission (EVAP) Purge System=Leaking—Greater than a predefined threshold

DTC P0442=Type A DTC

DTC P0455=Type B DTC

DTC P0442=Type A DTC

DTC P0455=Type B DTC

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Control Module References

• CH-48096 - EVAP Service Port Access Tool
• GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)
• GE-41413-SPT - High Intensity White Light
• GE-41413-300 - EVAP Cap and Plug Kit
• EN-41413-VLV - EVAP Service Port Vent Fitting

Equivalent regional tools:Special Tools

1. Verify the following conditions do not exist:
• Q12 Evaporative Emission Purge Solenoid Valve—Disconnected/Incorrect connection/Leaking/Loose/Stuck Closed—Not Purging/Visible Damage
• Q13 Evaporative Emission Vent Solenoid Valve—Disconnected/Incorrect connection/Leaking/Loose/Visible Damage
• Evaporative Emission Canister—Disconnected/Incorrect connection/Leaking/Visible Damage
• Evaporative Emission Hose&Evaporative Emission Pipe—Defective/Disconnected/Incorrect connection/Kinked/Leaking/Loose/Restricted/Visible Damage
• {Cap Type Fuel Fill}Fuel Tank Filler Cap—Defective/Leaking/Loose/Missing/Visible Damage
• {Capless Type Fuel Fill}Door@Fuel Tank Filler Pipe—Defective/Leaking/Loose/Missing/Stuck Open/Visible Damage
• If a condition exists

  Repair or replace as necessary

• If no condition exists

Note:

• Before proceeding with this test, review the tool user manual for Safety Information and Instructions:GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)
• The user manual that is supplied with the tool, is also available online, refer to:GM Special Service Tools
• Make sure the underbody temperature of the vehicle and the tester temperature are similar.
• Completely unwind the nitrogen/smoke hose from the bracket to optimize the tester's performance.

2. Perform the following action:
1. Install»Hose@Test Orifice—0.51 mm (0.020 in)@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)
2. Select»Nitrogen@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)
3. Press and release the switch:Remote Switch@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)—Special Tool=OnorActivated
4. Align—Sliding Red Flag@Floating Indicator
5. Press and release the switch:Remote Switch@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)—Special Tool=OfforDeactivated
3. Remove»Hose@Test Orifice
4. Disconnect the component:Quick Connect Fitting@Q12 Evaporative Emission Purge Solenoid Valve
5. Install»CH-48096 - EVAP Service Port Access Tool—Between:Evaporative Emission Canister Purge Tube&Q12 Evaporative Emission Purge Solenoid Valve
6. Install»GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)—Hose@CH-48096 - EVAP Service Port Access Tool
7. Ignition » On / Vehicle » In Service Mode
8. Perform the scan tool function:EVAP Vent Solenoid Valve»Not Venting

Note:

• The pressure must not exceed 13 in H2O (0.5 PSI) as pressure in excess of this could cause system components to perform inaccurately.
• 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.

9. Press and release the switch:Remote Switch@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)—Special Tool=OnorActivated

Verify the tool reading:Floating Indicator=Below:Sliding Red Flag

• If not below the Sliding Red Flag
1. Press and release the switch:Remote Switch@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)—Special Tool=OfforDeactivated
2. Select»Smoke@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)

Note:

• When injecting smoke in to the system, remove the fuel fill cap or temporarily leave the EVAP vent valve open, until smoke is observed. Then close the system.
• Verify smoke has filled the system by opening the system opposite the end where smoke is injected.
• To help locate intermittent leaks move related components while applying smoke to the system.

3. Press and release the switch:Remote Switch@GE-41413-A / B / C - Evaporative Emissions System Tester (EEST)—Special Tool=OnorActivated
4. Use the special tool:GE-41413-SPT - High Intensity White Light—Illuminate the area(s) of concern—Evaporative Emission (EVAP) System

   Verify the condition does not exist:Smoke exiting the component/system

• If a condition exists » Repair or replace as necessary
• If no condition exists
5. Repeat the procedure starting at step 1
• If below the Sliding Red Flag
10. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

    Verify the DTC does not set.

• If the DTC sets

  Repeat the procedure starting at step 1

• If the DTC does not set
11. All OK.

Perform the Diagnostic Repair Verification after completing the repair:Diagnostic Repair Verification

• Evaporative Emission Canister Replacement
• Evaporative Emission Canister Vent Solenoid Valve Replacement