Test the tractor protection valve by:

Question

You should test the tractor protection valve by allowing the air supply to properly charge, turning off the engine, then releasing air from the system by pressing the brake pedal several times. The tractor protection valve should move into its emergency position when psi drops to an unsafe level.

Accepted Answer

Releasing air with the brake pedal.

Answer

Removing the air supply knob.

Answer

Removing the parking brake control knob.

Answer

Releasing air with the gas pedal.