P0442
DTC P0442
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0442
- Evaporative Emission (EVAP) System Small Leak Detected
Circuit/System Description
The engine off natural vacuum (EONV) test is the small leak detection diagnostic for the evaporative emission system. This diagnostic tests the evaporative emission (EVAP) system for a small leak when the key is turned OFF and the correct conditions are met. Heat from the exhaust system is transferred into the fuel tank while the vehicle is operating. When the vehicle 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 engine control module (ECM) using the fuel tank pressure (FTP) sensor input. With a leak in the system, the amount of pressure change will be less than that of a sealed system.
Conditions for Running the DTC
* DTCs P010C, P010D, P012B, P012C, P012D, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0222, P0223, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P0502, P0503, P0722, P0723, P1221, P2227, P2228, P2229, P2610 are not set.
* The barometric pressure (BARO) is greater than 70 kPa.
* The fuel level is between 10-90 %.
* The start-up engine coolant temperature (ECT) and the start-up intake air temperature (IAT) are between 0-40°C (32-104°F).
* The engine run time before engine shut-off was greater than 10 min.
* The drive distance before engine shut-off was more than 8.4 km (5.2 mi).
* The ignition is OFF.
* The ambient air temperature at the end of the drive cycle is between 0-34°C (32-93°F).
* DTC P0442 runs once per drive cycle during the hot soak period after the ignition is turned OFF and may require up to 40 min to complete. The controller will not make more than 2 test attempts per day. The time since the last completed EONV test must be at least 17 h.
Conditions for Setting the DTC
* The ECM detects a leak in the EVAP system that is greater than a calibrated amount.
* The ECM must complete several EONV tests before the diagnostic can turn the MIL on or off.
Action Taken When the DTC Sets
DTC P0442 is a Type A DTC.
Conditions for Clearing the DTC
DTC P0442 is a Type A DTC.
Diagnostic Aids
* The EVAP system can be filled with smoke more quickly and completely by opening the system opposite the end where the smoke is injected. When injecting smoke at the service port tool temporarily leave the EVAP vent solenoid valve open until smoke is observed then close the system and continue testing.
* To help locate intermittent leaks using the GE-41413-A - evaporative emissions system tester (EEST), move all EVAP components while observing smoke with the GE-41413-SPT - high intensity white light.
* Individual components can be isolated and tested using adapters in the GE-41413-300 - EVAP cap and plug kit.
* 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 FTP parameter for vacuum decay.
Reference Information
Schematic Reference
Engine Controls Schematics ((LFX)) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Evaporative Emission Control System Description Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
* CH-48096 - EVAP Service Port Access Tool
* GE-41413-A - Evaporative Emissions System Tester (EEST)
* GE-41413-300 - EVAP Cap and Plug Kit
* GE-41413-SPT - High Intensity White Light
For equivalent regional tools, refer to Special Tools (Diagnostic Tools) Tools and Equipment.
Circuit/System Testing
Note:
* Refer to the GE-41413-A - evaporative emissions system tester (EEST)operation manual for detailed instructions in Evaporative Emission System Diagnosis Evaporative Emission System Diagnosis.
* Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.
* Ensure that the underbody temperature of the vehicle and the tester are similar.
1. Disconnect the purge tube at the quick connector on the EVAP canister side of the Q12 evaporative emission purge solenoid valve and install the CH-48096 - EVAP service port access tool.
2. Connect the GE-41413-A - evaporative emissions system tester (EEST)to the CH-48096 - EVAP service port access tool.
3. Using a scan tool close the EVAP vent solenoid valve to seal the EVAP system.
4. Use the flow meter on the GE-41413-A - evaporative emissions system tester (EEST), calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system.
• If a leak is detected, use the GE-41413-A - evaporative emissions system tester (EEST)to apply smoke to the EVAP system at the purge tube until the leak is located using the GE-41413-SPT - high intensity white light.
Repair Verification
1. Seal the EVAP system and use the flow meter on the GE-41413-A - evaporative emissions system tester (EEST), calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system.
2. Clear DTCs.