If the service line comes apart while you are driving a combination vehicle, but the emergency line stays together, what will happen right away?

Question

Accepted Answer

C: Nothing is likely to happen until you try to apply the brakes.. When attempting to apply the brakes air loss from the leaking service line will quickly lower the air tank pressure. If the air pressure falls low enough the trailer emergency brakes will apply.

If the service line comes apart while you are driving a combination vehicle, but the emergency line stays together, what will happen right away?

California CDL Combination Vehicles Test Info