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Engine Controls - DTC P0446
SOURCE: Kia PitStop
TITLE: DTC P0446
APPLIES TO: Optima
SERVICE TIP:
When diagnosing an Optima with a DTC P0446 (EVAP emission control system vent circuit malfunction), be aware that more than a faulty CCV or the electrical circuits to the CCV may be causing the DTC.
Because the ECM tests the function of the CCV by monitoring the fuel tank pressure sensor (FTPS) under various operating conditions, a malfunctioning FTPS may also set a P0446. The vent orifice on the FTPS on some vehicles has been found to be partially or completely plugged with undercoating. This vent orifice must be open to atmospheric pressure, or sluggish response to changes in evaporative system pressure will result. Replace the FTPS and retest if a plugged vent orifice is found. Some other Kia models have a short hose on the FTPS vent orifice, which should also be checked for plugging when diagnosing a stubborn evaporative system problem.