I rear ended to another car when I blacked out for a few seconds in the city driving around 20 miles an hour. The AEB, based on TESLA manual and instructions should have kicked in, but it never did. After the accident, a friend of mine told me about AEB function and the fact that it works in those type of conditions, I tested the car in my driveway (I have a pretty long driveway to do this). AEB did not kick in until I turned off the function and I turned on the function again. Then, it kicked in immediately, and on the screen "A" showed, which means AEB kicked in. That was the first time AEB worked and that sign appeared on the screen. Later in the day, when I tested the car again under the exact same conditions,, AEB stopped functioning again like the way it has been since I bought the car. I read all the information/instructions regarding AEB. I understand that in certain conditions like, if the driver is accelerating or putting pressure on brake pedal or steering wheel, AEB does not kick in. I talked to another TESLA owner, he said his does not kick in either unless the car is on auto cruise or autopilot. Mine is the same. This is definitely malfunction. The issue is that the car, on the screen shows that AEB is always turned on, but it never kicks in and the car does not give any error regarding this issue. Again, I tested it after turning off and on AEB function, and I now know the difference. Under the same conditions of that testing, the AEB does not function at all.