P0499 – Evaporative Emission System Vent Valve Control Circuit High

P0499 Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P0499 Possible Causes

Faulty Canister Close Valve (CCV),Canister Close Valve harness is open or shorted,Canister Close Valve circuit poor electrical connection,Faulty Engine Control Module (ECM)

P0499 Description

The Evaporative Emissions (EVAP) system prevents Hydrocarbon (HC) vapors from the fuel tank from escaping into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The Canister Close Valve (CCV) closes off the air inlet into the canister for leak detection of the evaporative emission system. The CCV also prevents fuel vapors from escaping from the canister. When the engine purges the HC vapors from the canister, the clean air comes into the canister through the canister air-filter and the CCV.