Which of these is not a part of the basic configuration of an ABS?
- Wheel speed sensor
- An electronic control unit
- Throttle position sensor ✓
- ABS valves
Answer: C. Throttle position sensor
The throttle position sensor is not part of the basic ABS configuration; ABS uses wheel speed sensors, an electronic control unit, and ABS valves.
Why this is the answer
The handbook describes ABS as working from wheel speed signals. Those pulses are monitored by an electronic control unit, which signals electrically controlled solenoid air valves to release and reapply brake pressure at the affected wheels. Automatic traction control is described as an optional addition that reuses wheel sensors, but no throttle position sensor is listed among the ABS parts. So the throttle position sensor does not belong with the ABS components named in the passages.
Why the other answers are wrong
- A. Wheel speed sensor — Wheel speed sensors are part of the ABS setup: the passages say ABS uses pulsating wheel-speed signals and that traction control reuses the same wheel sensors.
- B. An electronic control unit — The electronic control unit is the computer that monitors the wheel-speed signal and commands the ABS valves, so it is part of the system.
- D. ABS valves — The electrically controlled solenoid air valves, often called modulators, are what the ECU signals to release brake pressure, so they are ABS components.
Remember it
Remember the ABS signal path: wheel sensor to computer to brake valve.