P0442

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) tests the Evaporative Emission (EVAP) system for the following conditions:
^ Large and small leaks
^ Excess vacuum
^ Purge flow during non-commanded conditions
^ Fuel level and fuel pressure sensor faults
^ EVAP purge and vent valve faults

The PCM monitors the fuel tank pressure sensor in order to determine the level of vacuum or pressure in the EVAP system. The PCM commands both the EVAP purge solenoid and the EVAP vent valve ON when the Conditions for Running the DTC are met in order to apply an engine vacuum to the EVAP system. The PCM commands the EVAP purge solenoid OFF once the system has reached a predetermined level of vacuum. The EVAP system should HOLD the vacuum in the sealed system. The PCM sets this Diagnostic Trouble Code (DTC) in order to indicate a small leak if the EVAP system fails to hold a predetermined level of vacuum for a predetermined length of time. This DTC sets after failing the above test twice.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0107, P0108, P0110, P0112, P0113, P0115, P0117, P0118, P0121, P0122, P0123, P0125, P0440, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121, or P1122 are not set.
^ The Barometric Pressure (BARO) is more than 75 kPa.
^ The fuel level is between 15-85 percent of full capacity.
^ The Throttle Position (TP) sensor angle is less than 75 percent.
^ The vehicle speed is less than 102 km/h (65 mph).
^ The Engine Coolant Temperature (ECT) is between 4-30°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.

CONDITIONS FOR SETTING THE DTC
The vacuum in the EVAP system decays or leaks at too fast a rate.

IMPORTANT: This DTC does NOT report a first failed test. A first fail of this DTC will have a scan tool status as Not Run. Use the scan tool data display parameter of EVAP test result to determine if this DTC has failed or passed for this ignition cycle.

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 lime the diagnostic tails. 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.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
^ An accurate indication of fuel level is required for the PCM to properly pass or fail this DTC. Always diagnose fuel level sensor DTCs before performing this DTCs diagnostic table. Always inspect for fuel level sensor DTCs stored as History.
^ The Service Bay Test may have to be performed in cold ambient air temperatures when the vehicle is running a winter grade fuel. The scan tool displays a message when the service bay test does not run.
^ Inspect for charcoal release from the vapor canister. Refer to Evaporative Emission (EVAP) System Cleaning procedure. Service and Repair

CONDITIONS FOR RUNNING THE SERVICE BAY TEST
^ The battery voltage is between 10.5-17.5 volts.
^ The fuel level is between 15-85 percent of the full capacity.
^ The engine temperature is between 3.5-35°C (38-95°F).

Perform a physical inspection of the EVAP system. Inspect for the following conditions:
^ A loose, missing, defective, or incorrect fuel tank cap
^ Incorrectly routed or defective EVAP system vacuum and vapor lines
^ A malfunctioning or damaged vapor canister
^ Charcoal release from the vapor canister-Refer to Evaporative Emission (EVAP) System Cleaning. Service and Repair




The vacuum and pressure in the EVAP system is measured in inches of water (H2O). Most gauges measure vacuum in inches of mercury (Hg) and pressure in pounds per square inch (psi). The table shows how the values compare:

TEST DESCRIPTION

Steps 1-4:

Step 5:

Steps 6-7:

The numbers below refer to the step numbers on the diagnostic table.
4. This step verifies that a failure condition is active.
6. This step verifies that repairs are complete and that no other condition is present.