1 Answer

Hopefully this explains it. The real difference is the Hold button. If you understand that, then you can understand the rest. Your owner's manual will have this information also. 

D with HOLD behavior:

1st and 4th gears are locked out. You only have 2nd gear when accelerating from a standstill. You'll get an early shift to 3rd gear once ~15mph is exceeded. After the shift to 3rd, 2nd gear is then locked out along with 1st and 4th until you stop again.

S with HOLD behavior:
1st, 3rd, 4th gears locked out -- You have 2nd gear only.

L with HOLD behavior:
2nd, 3rd, 4th gears locked out -- You have 1st gear only.

I think D with HOLD is a good setting for traffic congestion. It prevents needless shifting between 2nd, 3rd and 4th gear since you're never get up to 35mph before you have to slow down for the cars in front anyway and once everyone does accelerate, it's done at a very slow rate, so 3rd gear can easily manage. When traffic does come to a stop, the 2nd gear starts are very smooth and don't require much throttle input to keep up with the car in front. Engine braking is also better at slower speeds, which also adds to the driving. http://forums.mazdaworld.org/100-millenia/62239-hold-button.html