P0442

Diagnostic Chart:

SMALL LEAK DETECTED
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 canister purge valve 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 80.8 kPa.
^ Both ECT and IAT are between 5°C (41°F) and 32°C (90°F) at engine start up.
^ IAT and ECT are within 10 degrees of each other at start up.
^ Fuel tank level is between 15% and 85%.
^ Engine run time is greater than 2 seconds.
^ DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0452, P0453, and P0500 are not set.
^ A vacuum decay slope is greater than a calibrated amount during the test. The decay slope is proportional to fuel level.

DIAGNOSTIC AIDS
Check for the following conditions:
^ Missing or leaking O-rings at fuel vapor line connections or fuel sender.
^ 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.