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Home >> Chevrolet >> 2001 >> Cavalier LS, 2.2 4 >> Repair and Diagnosis >> External Pages >> Different car >> Section 256 (Engine Controls Diagnosis, (DTC P0300 To DTC P1171) - 2.2L (L61)) >> Diagnostic Trouble Codes >> DTC P0446 >> System Description

System Description

WARNING: This page is about a different car, the 2004 Pontiac Sunfire and 2004 Chevrolet Cavalier. 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. The control module commands the EVAP canister purge solenoid valves Open and the EVAP canister vent solenoid valves Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valves Closed and the EVAP canister vent solenoid valves Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

DTC P0446

Control Module Command EVAP Canister Purge Solenoid EVAP Canister Vent Solenoid
ON Open Closed
OFF Closed Open
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