Hi Keith,

You've not told us which car you have so our answer will have to be general. It sounds to me that you've inadvertently changed the trip display in your instrumentation. The "A" is usually one of two different trip values available to you, other than the total, which obviously you cannot change. You'll need to find the button that alters this display if you want to revert to how it was. Some cars have buttons near the instruments themselves, some on the indicator stalk and others on the spokes of the steering wheel.