Manitoba Airbrake Practice Exam

The low air-pressure warning device is responsible for notifying the driver of low air-pressure in the vehicle's tires. This is a crucial safety feature as it helps prevent accidents and damage to the tires and vehicle. In order for the device to accurately test the air-pressure, the engine and ignition must be in a specific state.

Option A is incorrect because the engine needs to be running in order to accurately test the air-pressure. With the engine off, the device will not be able to accurately detect the air-pressure in the tires.

Option B is also incorrect for the same reason as option A - without the engine running, the device cannot accurately test the air-pressure.

Option D is incorrect because the ignition needs to be off in order to test the air-pressure warning device. With the ignition on, the device may not work properly and could give inaccurate readings.

Therefore, option C is the correct answer