Jeep Repair: engine code PO499, jeep wrangler, vent valve

Question
My engine light came on in my 05 Jeep Wrangler....the code reads P0499....Valve control high. Could you please tell me what this is and how do I fix it. thanks.

Answer
P0499-NVLD CANISTER VENT VALVE SOLENOID CIRCUIT HIGH

POSSIBLE CAUSES
GOOD TRIP EQUAL TO ZERO
VEHICLE HISTORY AND SERVICE BULLETIN INVESTIGATION
NVLD SOLENOID
NVLD SOL CONTROL CIRCUIT SHORTED TO BATTERY VOLTAGE
NVLD SOL CONTROL CIRCUIT OPEN
GROUND CIRCUIT OPEN
PCM