Deck 53: Antilock Brake, Traction Control, and Stability Control Systems

Question 1

Most of the service done to the brakes of an antilock brake system is identical to that in a conventional brake system.

Answer 1

True

Question 2

ABS solenoid valves are electrically operated by signals from the control module.

Answer 2

True

Question 3

The ABS pump motor switch turns the pump on and off to maintain 200 to 261 psi (1,379 to 1,800 kPa) of hydraulic pressure in the accumulator.

Answer 3

False

Question 4

ABS pressure modulation works to prevent wheel locking.

Question 5

The pump on a nonintegrated-type ABS system is continuously on during an ABS stop and remains on for about five seconds after the stop is complete.

Question 6

A wheel speed sensor generates a DC voltage as a toothed ring passes the sensor's coil.

Question 7

Brake service on an ABS-controlled vehicle is similar to that of a non-ABS-equipped vehicle.

Question 8

Nonintegral ABS systems use a conventional vacuum-assist booster and master cylinder.

Question 9

The signal produced by wheel speed sensors can be affected by radio frequency interference (RFI).

Question 10

The majority of antilock brake systems are of the integrated design.

Question 11

With ABS, the brake pedal feel during hard [panic stop] braking is similar to that of a conventional power brake system.

Question 12

Before removing the master cylinder on an ABS system with a high-pressure accumulator, the accumulator must be discharged by ______.

A) pumping the brake pedal twenty-five times with the ignition off
B) loosening a bleeder screw on the master cylinder with the ignition on
C) loosening the accumulator one-eighth of a turn with the ignition switch off
D) disconnecting the pump motor and pumping the brake pedal ten times

Question 13

An ATC system controls positive wheel spin by modulating hydraulic pressure applied to the brakes on the wheel that is spinning to slow down the wheel.

Question 14

Nonintegrated ABS systems do not use an electric pump or accumulator.

Question 15

An ABS speed sensor may be located on an axle's differential gear housing.

Question 16

Pumping the brake pedal quickly during ABS activation will assist the antilock brake system to function properly.

Question 17

A tire on the verge of slipping produces less friction with respect to the road than one that is locked and skidding.

Question 18

Two solenoid valves are used to control each hydraulic circuit or channel.

Question 19

The most effective and most common ABS available is a two-channel system, in which sensors monitor the front and rear wheels.

Question 20

Antilock brake systems are highly effective in stopping a vehicle driving over loose snow.

Question 21

What is the name of the gas-filled pressure chamber that is part of the antilock brake system's pump and motor assembly?

A) control sump
B) accumulator
C) sump chamber
D) reservoir

Question 22

Automatic stability control systems help correct _____ by applying the inner or outer wheel brakes.

A) oversteer
B) understeer
C) both "oversteer" and "understeer"
D) neither "oversteer" nor "understeer"

Question 23

Technician A says a malfunction of the ABS causes the control module to shut off or inhibit the system. Technician B says a loss of hydraulic fluid or power booster pressure disables the antilock brake system. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 24

The modulator unit is sometimes called a(n) ______.

A) hydraulic actuator
B) hydraulic power unit
C) electro-hydraulic control valve
D) all answers are correct

Question 25

Technician A says some antilock brake systems use a lateral acceleration sensor in addition to the wheel speed sensors. Technician B says traction control systems apply one wheel brake to control oversteer while turning. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 26

Technician A says if the amber brake lamp is on continuously, an ABS code is stored in the ABS control module. Technician B says on some vehicles, the amber ABS warning light will flash out digital trouble codes. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 27

Technician A says the wheel speed sensor air gap cannot be adjusted. Technician B says wheel speed sensors can be tested with a lab scope. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 28

While road testing a car equipped with an antilock brake system, Technician A says during heavy braking, several pulses may be felt through the brake pedal. Technician B says a spongy pedal during normal braking is acceptable. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 29

Technician A says a loss of hydraulic fluid disables the antilock brake system. Technician B says a loss of power booster pressure disables the antilock brake system. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 30

An accumulator is normally charged with ______.

A) halogen
B) hydrogen
C) nitrogen
D) oxygen

Question 31

Which of the following is NOT a component of an antilock brake system?

A) power steering pump
B) master cylinder
C) solenoid valve body assembly
D) wheel sensors

Question 32

Technician A says ABS systems provide superior directional stability when the brakes are applied while turning a corner. Technician B says ABS systems provide superior braking when driving on loose snow. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 33

Antilock brake systems can modulate the pressure to the brakes as often as _____ times per second.

A) five
B) fifteen
C) fifty
D) sixty

Question 34

Technician A says in one-channel systems, the rear brakes on both sides of the vehicle are modulated at the same time to control skidding. Technician B says most single-channel systems have a wheel speed sensor at each rear wheel. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 35

Technician A says integral ABS systems use a vacuum-type power brake booster. Technician B says nonintegral ABS systems use a hydraulic-type power brake booster. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 36

When the ABS is activated when a wheel begins to lock, the brake pedal should ______.

A) drop about one inch
B) should go from hard to spongy
C) make you feel a small bump followed by rapid pedal pulsations
D) all answers are correct

Question 37

Technician A says if the amber ABS warning light is on continuously, the ABS system is still operational but may not be operating at 100 percent efficiency. Technician B says ABS operation might be affected by improperly turning the drums and rotors. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 38

The amber ABS brake warning light is illuminated with the engine running. The most likely cause of this problem is _____.

A) a leak at the wheel caliper
B) a restricted brake hose
C) a faulty wheel speed sensor
D) excessive pedal free play

Question 39

Automatic traction control (ATC) is being discussed. Technician A says vehicles with ATC typically do not have an antilock brake system. Technician B says ATC applies extra torque to a drive wheel that is spinning and losing traction. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 40

An accumulator ______.

A) stores hydraulic fluid to maintain high pressure in the brake system
B) provides residual pressure for power-assisted braking
C) both "stores hydraulic fluid to maintain high pressure in the brake system" and "provides residual pressure for power-assisted braking"
D) neither "stores hydraulic fluid to maintain high pressure in the brake system" nor "provides residual pressure for power-assisted braking"

Question 41

Electronic stability control [ESC] systems are being discussed. Technician A says the brake at the inside rear wheel is applied when the system detects an understeer condition. Technician B says ESC can extend a car's physical limits and can increase traction. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 42

Technician A says an integral-type ABS system uses accumulator pressure to provide power brake assist. Technician B says the integral ABS system uses accumulator pressure [boost pressure] to operate the rear brakes. Who is correct?

A) A only
B) B only
C) both A and B
D) Neither A or B

Question 43

ATC systems are being discussed. Technician A says in order to use the brakes to control wheel spin, the ABS must have a pump to develop hydraulic pressure and an accumulator to store reserve pressure. Technician B says the pulse rings and wheel-speed sensors for ATC systems are located inside the transmission and are different from ABS wheel speed sensors. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 44

Technician A says the steering ability of the vehicle is reduced if the front wheels are locked. Technician B says the stability of the vehicle is reduced if the rear wheels are locked. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 45

When the vehicle is road tested after replacement of an axle shaft, the ABS warning light turns on. Technician A says count the number of teeth on the toner ring of the old axle and compare it to the new axle. Technician B says perform an ABS speed sensor relearn procedure. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 46

Technician A says ABS wheel speed sensors are Hall-effect-type sensors. Technician B says ABS sensors are PM generators. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 47

An accumulator unit is typically found on vehicles with _____.

A) four-wheel disc brakes
B) hydraulically assisted power brakes
C) vacuum-assisted power brakes
D) disc front and drum rear brakes

Question 48

Technician A says silicone-based brake fluid should always be used on ABS brake systems. Technician B says DOT 3 is the recommended fluid for most ABS systems. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 49

Which of the following ABS components is NOT part of the hydraulic control unit?

A) solenoid valves
B) pump and an electric motor
C) fluid accumulators
D) proportioning valves

Question 50

In addition to wheel speed sensors, ESC systems also require a _____.

A) steering angle sensor
B) lateral-acceleration sensor
C) yaw sensor
D) all answers are correct

Question 51

The yaw rate sensor and lateral accelerometer share the same housing and are located _____.

A) inside the PCM
B) inside the EBCM
C) in the center of the vehicle
D) in the trunk

Question 52

The function of the pressure switch in the hydraulic control unit is to ______.

A) activate the ABS warning light
B) trigger the solenoids when pressure has exceeded preset limits
C) turn the booster pump off and on
D) all answers are correct

Question 53

Which of the following is not a location for the toothed ring [toner ring]?

A) axle shaft
B) differential carrier
C) wheel hub
D) modulator unit

Question 54

Technician A says the solenoid valves inside the modulator unit are used to decrease brake pressure. Technician B says the solenoids are used to increase pressure. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 55

Driving an ABS vehicle is being discussed. Technician A pumps the brake pedal during hard braking. Technician B applies steady pressure to the brake pedal. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 56

Technician A says three-channel ABS systems have individual hydraulic circuits to each of the two front wheels, and a single circuit to the two rear wheels. Technician B says a three-channel ABS system has four sets of solenoids in the hydraulic unit. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 57

Technician A says information from the wheel speed sensors is available to other control modules on the CAN network. Technician B says wheel speed sensors are AC generator-type sensors. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 58

Technician A says understeer is a condition where the vehicle is slow to respond to steering changes. Technician B says oversteer occurs when the rear wheels try to swing around or fishtail. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 59

When activated, the dump valve sends hydraulic pressure to the ______.

A) master cylinder reservoir
B) wheel cylinder/caliper
C) fluid accumulator
D) master cylinder primary chamber

Question 60

In an integral ABS system, the antilock hydraulic control valve assembly is located on the ______.

A) driver's side inner front fender
B) master cylinder
C) both "driver's side inner front fender" and "master cylinder"
D) neither "driver's side inner front fender" nor "master cylinder"

Question 61

In a one-channel ABS system, only the ____________________ brakes on both sides of the vehicle are modulated at the same time to control skidding.

Question 62

An antilock brake system's electric pump and motor assembly is often called the ____________________ pump.

Question 63

Identify the resource for determining ABS brake bleeding procedures and why it should always be used.

Question 64

The ____________________ provides access and/or control of vehicle information, operating conditions, and diagnostic information.

Question 65

If the brake fluid level is below minimum, the _____ warning lamp will turn on.

A) red
B) amber
C) both "red" and "amber"
D) neither "red" nor "amber"

Question 66

DOT ____________________ brake fluid is recommended for most antilock systems.

Question 67

Modern antilock brake systems provide electronic/hydraulic ____________________ of the brakes for straight-line stopping during panic conditions.

Question 68

An integrated system is often called a(n) ____________________ system.

Question 69

The ____________________ pump is used to provide pressurized hydraulic fluid for the ABS.

Question 70

The ____________________ acceleration sensor monitors acceleration, deceleration, and cornering forces [the sideward movement of the vehicle while it is turning a corner].

Question 71

G-force is a measurement of a vehicle's ____________________.

Question 72

The ABS ____________________ module monitors system operation and commands antilock functions when needed.

Question 73

All vehicles have a(n) ____________________colored warning lamp to indicate a problem in the vehicle's conventional brake system.

Question 74

All vehicles have a(n) ____________________-colored warning lamp to indicate a problem in the vehicle's antilock brake system.

Question 75

The rapid application and release of brake pressure used to prevent wheel lock is called ____________________.

Question 76

Explain the role of the wheel sensors in an antilock brake system.

Question 77

Explain the difference between an integrated and a nonintegrated antilock braking system.

Question 78

Technician A says when the ignition switch is turned to the start position, both the red and amber brake warning lights should turn on. Technician B says after the engine starts, the amber ABS warning light should turn off after three to five seconds if the system passes its self-test. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 79

A(n) ____________________ is a numeric identifier for a fault condition identified by the ABS system's internal diagnostic system.

Question 80

What is the primary difference between automatic traction control systems and stability control systems?