Question

When does the tractor protection valve close automatically?

Accepted Answer

when the air pressure is low and ranges from 25 psi to 45 psi

Answer

It doesn't close off automatically; you need to close the valve yourself.

Answer

when the air pressure is high and reaches 45 to 60 psi

Answer

when the air pressure is low and reaches 30 psi to 55 psi

Question 8 - Combination Vehicles Test Practice Test for the CDL