The application pressure gauge shows:

How much air pressure you are applying to the brakes.. Section 5.1: The application pressure gauge shows how much air pressure you are

The application pressure gauge shows:

ANSWER BREAKDOWN
  • A. Incorrect. "How much air is in the tank." is not correct. The application pressure gauge shows how much air pressure you are applying to the brakes (pedal pressure).
  • B. Correct. The application pressure gauge shows how much air pressure you are applying to the brakes (pedal pressure).
  • C. Incorrect. "How much air the compressor is pumping." is not correct. The application pressure gauge shows how much air pressure you are applying to the brakes (pedal pressure).
  • D. Incorrect. "The temperature of the brakes." is not correct. The application pressure gauge shows how much air pressure you are applying to the brakes (pedal pressure).