P0442

Diagnostic Chart:

The evaporative emission system is tested with on-board diagnostics by applying pressure (vacuum) to the system and monitoring pressure decay. The PCM monitors the vacuum level through the fuel tank pressure sensor. At the appropriate time, the vent solenoid is commanded closed (normally open valve) and the canister purge solenoid is commanded to a fixed duty cycle, allowing the engine to draw a vacuum on the entire evaporative emission system. After a calibrated vacuum level is achieved, the EVAP purge solenoid is turned off, sealing the system. A leak is detected by monitoring for a decrease in vacuum level over a calibrated period of time, while keeping all other variables constant.

DTC PARAMETERS
^ Baro is greater than 75 kPa.
^ Both ECT and IAT are between 4°C (39°F) and 30°C (86°F) at engine start up.
^ ECT is not more than 8°C (14°F) greater than IAT at startup.
^ Throttle angle is between 7% and 35%.
^ Vehicle speed is less than 113 km/h (70 mph).
^ EVAP purge solenoid is enabled.
^ IAT is not more than 1.5°C (3°F) greater than ECT at startup.
^ Fuel tank level is between 15% and 85%.
^ DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0452, P0453, P0502, P0503, P0601, P0602, P1133 and P1621 are not set.
^ A vacuum decay is greater than a calibrated amount during the test.

DIAGNOSTIC AIDS
Check for the following conditions:
^ Missing or leaking O-rings at fuel vapor line connections or fuel tank unit.
^ Cracked or damaged EVAP canister.
^ Damaged source vacuum line, EVAP purge line, EVAP vent hose or fuel tank vapor line.
^ Leaking fuel tank or filler neck.
^ Use the EVAP Pressure/Purge Diagnostic Cart and the Ultrasound leak Detector to locate leak.