You should know the process of solving the car problem and know the meaning of the car engine P2640 Code. The computer posters the canister is empty when it notices a leaner disorder what all the vapors are used up and it restarts normal fuel distribution. Some car manufacturers then close the vent solenoid but leave the laxative solenoid open. That makes a vacuum through the whole fuel storage system. Once the right vacuum is touched, it locked the purge solenoid and delays to understand if the vacuum holds. Do not drive the car until the car engine is fixed properly.