P0442

DTC P0442

System Description

This DTC tests the evaporative emission (EVAP) system for a small leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the control module turns the EVAP canister purge solenoid valve ON and the EVAP canister vent solenoid valve ON. This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the control module turns the EVAP canister purge solenoid valve OFF, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum decay. If the control module detects a leak larger than a calibrated amount, this DTC sets.

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 solenoid valves.






DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0442 Evaporative Emission (EVAP) System Small Leak Detected

Conditions for Running the DTC

* Before the powertrain control module (PCM) can report that DTC P0442 failed, DTCs P0446, P0455, and P0496 must run and pass.
* DTCs P0111, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0443, P0449, P0452, P0453, P0462, P0463, P0503, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1121, P1122 are not set.
* The ignition voltage is between 10-18 volts.
* The barometric pressure (BARO) is more than 75 kPa.
* The fuel level is between 15-85 percent.
* The engine coolant temperature (ECT) is between 4-39°C (39-86°F).
* The intake air temperature (IAT) is between 4-30°C (39-86°F).
* The start up ECT and IAT are within 9°C (16°F) of each other.
* The vehicle speed sensor (VSS) is less than 129 km/h (80 mph).
* The vehicle must be driven more than 8.4 kilometers (5.2 miles).
* DTC P0442 runs once per cold start when the above conditions are met.

Action Taken When the DTC Sets

* The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
* The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC

* The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Clear the MIL and the DTC with a scan tool.

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.
* For intermittent conditions, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

Test Description

Step 1 - Step 4:

Step 5 - Step 7:

The numbers below refer to the step numbers on the diagnostic table.
3. Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
5. This step verifies that repairs are complete.