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Question:
When the tractor protection valve closes, it stops any air from going out of the tractor. It also lets the air out of the trailer emergency line. This causes the trailer emergency brakes to come on, with possible loss of control. [California Commercial Driver Handbook]
Comments
Alkam 2126
4 years ago
It a great app to study for your CDL tests
Cbow33
4 years ago
Great app
Livvy2u
4 years ago
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