The engine P1841 Code appears on the screen of the car code reader when the car engine is tested. Due to the sensor fault, the engine problem may have started. This problem is easy to fix but little expensive. Because you may need to replace parts from the car engine. So, you have to spend some money for solving the car engine. When you fill up the car with gas, the vapors in the tank get required into a cylinder occupied with started charcoal. Also, on a hot day as the gas temperatures increase and vaporizes, those similar vapors push into the container where they are stored.