Diagnostic Aids

If DTC P0446 is the only EVAP DTC set, the most likely cause is an inoperable EVAP canister vent solenoid, or pressure switching solenoid. Check EVAP solenoids carefully for faulty connections and erratic operation.
An intermittent malfunction may be caused by a fault in any of EVAP solenoid electrical circuits. Check wiring harness and components for an intermittent condition.
If DTC cannot be duplicated, information included in freeze frame data can be useful in determining vehicle operating conditions when DTC was first set.
Operating vehicle in CHECK MODE will increase ability of PCM module to detect engine control system malfunctions. See SERVICE BAY TESTS under SELF-DIAGNOSTIC SYSTEM.