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 (EVAP) system. This diagnostic tests the 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 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 P0096, P0097, P0098, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0128, P0443, P0446, P0449, P0452, P0453, P0455, P0461, P0462, P0463, P0496, P0502, P0503, P0722, P0723, P2066, P2067, P2068, P2227, P2228, P2229, P2610 are not set.
* The barometric pressure (BARO) is greater than 70 kPa.
* No fuel filling during the EONV test period.
* The fuel level is between 10-90 %.
* The start-up engine coolant temperature (ECT) and the start-up intake air temperature (IAT) are within 8°C (46°F).
* The engine coolant sensor (ECT) is greater 70°C (158°F)
* The engine run time before engine shut-off was greater than 10 min.
* The drive distance before engine shut-off was greater than 8 km (5 mi).
* The ignition is OFF and must stay off during the EONV test period or the test will abort.
* 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 7 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 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 - EVAP Service Port Vent Fitting at the service port to allow the system to fill faster.
* 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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Description and Operation
* Evaporative Emission Control System Description Description and Operation
* Hybrid Modes of Operation Description Hybrid Modes of Operation Description
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
* CH 48096 - EVAP Service Access Port Tool
* GE 41413-A - Evaporative Emissions System Tester (EEST)
* GE 41413-300 - EVAP Cap and Plug Kit
* J 41413-VLV - EVAP Service Port Vent Fitting
* GE 41413-SPT - High Intensity White Light
For equivalent regional tools, refer to Special Tools Tools and Equipment
Circuit/System Verification
1. Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description Hybrid Modes of Operation Description.
2. Ignition ON, verify the scan tool hood position parameter displays Open.
• If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.
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 or produce smoke from a leak.
* The fuel level should be between 1/4 and 3/4 of a tank.
* 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 Access Port Tool.
2. Connect the GE 41413-A - Evaporative Emissions System Tester (EEST) to the vehicle at theCH 48096 - EVAP Service Access Port 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 service port or 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.