Chapter 106 ABS Components and Operation
Two Techs are discussing ABS wheel speed sensors. Tech A says that some ABS systems use a sensor located in the rear-axle pinion gear area. Tech B says that tire chirp is normal during an ABS stop on dry pavement. Which Tech is correct?
Tech A
A customer wanted the ABS checked because of tire chirp noise during hard braking. Tech A says that the speed sensors may be defective. Tech B says that tire chirp is normal during an ABS stop on dry pavement. Which Tech is correct?
Tech B
Tech A says an ABS anti-lock system decreases pressure to the hydraulic brake circuits on wheels with excessive wheel slippage during deceleration. Tech B says traction control system increases pressure to the hydraulic brake circuit on wheels with excessive wheel slippage during acceleration. Which Tech is correct?
Tech B
Tech A says an anti-lock brake system will always produce the shortest possible stops. Tech B says when braking on loose gravel or dirt, a system that can lock the wheels produces shorter stops than an anti-lock system. Which Tech is correct?
Tech B
Tech A says an anti-lock system that operates on the select-low principle will control each rear wheel individually. Tech B says systems using the select-low principle regulates rear wheel brake pressure to both rear wheel simultaneously. Which Tech is correct?
Tech B
Tech A says digital wheel speed sensors produce a variable frequency AC voltage. Tech B says digital wheel speed sensors use a DC reference voltage supply and produce a square wave signal. Which Tech is correct?
Tech B
Tech A says that ABS-equipped vehicles can stop quickly and without skidding on all road surfaces even if covered with ice. Tech B says that steering is possible during an ABS stop. Which Tech is correct?
Tech B
A Tech is trying to identify which type of anti-lock system is installed on a vehicle. A speed sensor is attached to the rear differential housing. Which type of system could this be?
Three-Channel ABS
The faster a wheel rotates, the higher the frequency produced by a wheel speed sensor
True
Which anti-lock component creates current frequencies that change with wheel rotational speed?
Wheel Speed Sensors
Before servicing the brakes in a typical integral ABS, the Tech should pump the brake pedal
25 times or more
Which of the following is NOT a function of an anti-lock brake system (ABS)?
Allows drivers to drive more closely to the vehicle in front
Tech A says that ABS brakes are designed to allow the front wheel to be steered during heavy braking. Tech B says that an ABS dash warning lamp is amber. Which Tech is correct?
Both
Tech A says that most ABS units are non-integral. Tech B says that the ABS is disables (does not function) below about 5 mph (8 km/h). Which Tech is correct?
Both
Tech A says that some wheel speed sensors are enclosed in a wheel bearing assembly. Tech B says that some wheel speed sensors are exposed to possible damage from road debris. Which Tech is correct?
Both
Magnetic wheel speed sensors are being discussed. Tech A says that the wheel speed sensors are magnetic. Tech B says that the touched sensor ring is magnetic. Which Tech is correct?
Tech A
Which type of anti-lock braking system (ABS) requires the use of four wheel speed sensors?
Four Channel
The ABS computer uses the ---- signal from a wheel speed sensor
Frequency
Which of the following components is common to all vehicle equipped with ABS?
Hydraulic control unit
Tech A says that the ABS system may not result in shorter stopping distance compared to brakes without ABS. Tech B says that a pulsating brake pedal during normal braking is a characteristic feature of most ABS-equipped vehicles. Which Tech is correct?
Tech A
The standard ABS control strategy uses a three step cycle. These are
Pressure hold, pressure decrease and pressure increase
The maximum traction between a tire and the road occurs when he tire is
Slipping 10% to 20%
