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Home >> Pontiac >> 2009 >> Vibe Base, 2.4 0, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 157 (Engine Controls And Fuel - 4.6L - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P0446 >> Circuit/System Description

Circuit/System Description

WARNING: This page is about a different car, the 2011 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path that would cause excess amounts of vacuum to be developed in the EVAP system. With the purge valve open and the canister vent valve open, if the EVAP system vacuum goes above a calibrated threshold, the test will fail.

FTP Sensor Signal Voltage Fuel Tank Pressure
1.5 V Atmospheric Pressure/BARO
Less than 1.5 V Positive Pressure
More than 1.5 V Negative Pressure/Vacuum