Canon 50mm 1.8 non autofocus lens on * a * camera

I have a Canon 50mm 1.8 lens that when connected to my 100d does not auto focus.

I supposed the engine had run on the lens, as it worked well before

A friend recently let me borrow his camera kit, and the "broken" lens works well on his 5d, and the other five lenses work fine on both devices.

Is there a parameter on the 100d that I'm missing that could cause this problem?