Anti-lock braking systems (ABS) do NOT typically include
- wheel speed sensors
- brake lines
- valves
- tire pressure sensors ✓
Answer: D. tire pressure sensors
ABS does not typically include tire pressure sensors; the system is built around speed sensing, decision-making, and brake releasing or modulation.
Why this is the answer
The handbook describes ABS as having three main sections: speed sensing, decision-making, and brake releasing or modulation. It also notes that ABS is an addition to a normal air brake system, which is why the hardware that senses wheel speed and controls brake pressure belongs to the system. Tire pressure sensors are not part of that description, so they are the item ABS does not typically include.
Why the other answers are wrong
- A. wheel speed sensors — Wheel speed sensors fit the speed-sensing section that the handbook lists as one of the three main sections of ABS.
- B. brake lines — Brake lines are part of the normal air brake system that ABS is added to, so they are part of the braking hardware involved.
- C. valves — Valves are part of the brake releasing or modulation section the handbook names as one of the three main ABS sections.
Remember it
Think of ABS as three jobs: sensing wheel speed, deciding, and modulating brake pressure. Anything about tire air pressure is outside those three jobs.