回複：請教：NISSAN 99 QUEST “service engine soon" light on

Is your car NOT driven very often? If yes, it is the vent control valve is stuck at the open position. It only costs you $2.00 to fix the poblem if DIY. Take down the evap canister (a black box, and its size is about a gallon of water bottle) and vent control valve, which are located under the car. Remove the vent control valve from the evap canister, spray enough the WD-40 ($2.00) in and out the vent control valve, and wait for one day or two. You save $900.00. Good luck!