The fuel cap is an important part of any vehicle. This prevents gasoline from spilling out of the vehicle and can also prevent outside debris from entering your fuel tank. On motorcycles it is common for the fuel cap to have a lock on it to prevent someone from stealing your gas.
A Map Lamp is a small light in a vehicle the give a focused beam of light. These are different than the dome light and can be located in places like the rear view mirror. The purpose of these lights are to allow a passenger in the vehicle to view or read a map, directions, or see better in a specific portion of the vehicle without lighting up the whole vehicle.
Low Fuel is when your vehicle is running low on fuel. On most vehicles there is an indicator that will let you know when the vehicle is running low. Typically you should not rely on this indicator because they can often fail and leave you stranded for gasoline.
If you would like to see what your vehicles “Low Fuel” indicator looks like, refer to your owners manual.
An acceptable range of measurements