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 Emissions (EVAP) System Small Leak Detected
Circuit/System Description
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 a vehicle 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 corresponding pressure changes in the fuel tank vapor space. This change is monitored by the engine control module (ECM) using the fuel tank pressure sensor input. The ECM then makes a judgment on the integrity of the system. With a 0.51 mm (0.02 in) leak in the system, the amount of pressure change observed is significantly less than that of a sealed system.
Conditions for Running the DTC
Important: The following conditions must be met prior to ignition OFF.
* Before the ECM can report DTC P0442 failed, DTCs P0446, P0455, and P0496 must run and pass.
* DTCs P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0443, P0446, P0449, P0452, P0453, P0463, P0503, P1106, P1107, P1111, P1112, P1114, P1115, P1516, P2101, P2108, P2120, P2125, P2129, P2138, P2610 are not set.
* The diagnostic runs once after a cold start drive cycle.
* The start-up intake air temperature (IAT) is between 4-30°C (39-86°F).
* The start-up engine coolant temperature (ECT) is less than 30°C (86°F).
* The start-up IAT and ECT are within 8°C (15°F).
* The barometric pressure (BARO) is more than 74 kPa.
* The ambient air temperature is between 2-32°C (36-90°F).
* The engine run time minimum is 10 minutes.
* The vehicle has traveled more than 5 kilometers (3 miles) this trip.
* The ECT is more than 70°C (158°F).
* The fuel level is between 15-85 percent.
* The ignition is OFF.
* A refueling event is not detected.
* DTC P0442 runs once per drive cycle when the above conditions are met.
* One test occurs at ignition OFF after a drive cycle, and may require up to 45 minutes to complete. No more than 2 tests per day are allowed.
Conditions for Setting the DTC
* The ECM detects a pressure change that is less than a calibrated amount.
* The ECM must complete several engine OFF natural vacuum (EONV) tests before the diagnostic can turn the malfunction indicator lamp (MIL) ON or OFF.
Action Taken When the DTC Sets
DTC P0442 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P0442 is a Type A DTC.
Diagnostic Aids
* To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
* To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
* A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool Purge/Seal function to create a vacuum, seal the system and observe the FTP parameter for vacuum decay, this type of leak may be detected.
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 (Evaporative Emission Control System Description)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Special Tools
* CH-48096 EVAP Service Access Port Tool
* GE-41415-50 Fuel Tank Cap Adapter
* J 41413-200 Evaporative Emission System Tester (EEST)
* J 41413-300 EVAP Cap and Plug Kit
* J 41413-SPT High Intensity White Light
* J 41413-VLV EVAP Port Vent Fitting Tool
Circuit/System Testing
Note:
* Refer to the J 41413-200 - 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 evaporative emission canister side of the Q12 evaporative emission canister purge solenoid valve and install the CH 48096 - Port Tool.
2. Using a scan tool, close the EVAP canister vent valve to seal the EVAP system.
3. Use the flow meter on the J 41413-200 , 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 J 41413-200 to apply smoke to the EVAP system at the service port or the purge tube until the leak is located using the J 41413-SPT .
Repair Verification
The malfunction indicator lamp (MIL) may remain ON after the repair unless the DTCs are cleared.
1. Seal the EVAP system and use the flow meter on the J 41413-200 calibrated to 0.51 mm (0.020 in) to determine that there is no leak in the EVAP system.
2. Clear the DTCs.