DTC P0442: EVAP System - Small Leak: Description
WARNING: This page is about a different car, the 2001 GMC Savana, 2001 Chevrolet RV Cutaway, 2001 Chevrolet Cutaway, and 2001 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
Powertrain Control Module (PCM) tests 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.
PCM monitors Fuel Tank Pressure (FTP) sensor to determine level of vacuum or pressure in EVAP system. PCM commands both EVAP purge solenoid and EVAP vent valve on when code enable criteria are met to apply engine vacuum to EVAP system. PCM commands EVAP purge solenoid off once system has reached a predetermined level of vacuum. EVAP system should hold vacuum in sealed system. PCM sets this DTC to indicate a small leak if EVAP system fails to hold a predetermined level of vacuum for a predetermined length of time. DTC P0442 will set after failing test twice.