Question 1

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?

Accepted Answer

Technician A is correct because in one-channel ABS systems, the rear brakes are indeed modulated together to control skidding, while Technician B is incorrect as most single-channel systems typically have only one wheel speed sensor for the rear wheels, not one at each rear wheel.

Question 2

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

Accepted Answer

The modulator unit in various systems can be referred to as a hydraulic actuator, a hydraulic power unit, or an electro-hydraulic control valve, depending on its specific function and the context in which it is used.

Question 3

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?

Accepted Answer

Both Technician A and Technician B are correct. The amber brake lamp being on continuously indicates that an ABS code is stored in the ABS control module. Additionally, on some vehicles, the amber ABS warning light can indeed flash out digital trouble codes, allowing for a form of self-diagnosis.

Question 4

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?

Accepted Answer

Both technicians are correct. Technician A is correct because some antilock brake systems (ABS) indeed use a lateral acceleration sensor to help determine if the vehicle is experiencing sideways movement, which can be crucial for the ABS to function properly in certain situations. Technician B is correct because traction control systems can apply the brake to one of the wheels to control oversteer, helping to stabilize the vehicle during turns.

Question 5

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?

Accepted Answer

Technician B is correct because improperly turning the drums and rotors can affect ABS operation. Technician A is incorrect because if the amber ABS warning light is on continuously, it indicates a fault in the ABS system, and it may not be operational.

Question 6

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?

Accepted Answer

Technician A is correct because it is normal to feel pulses through the brake pedal during heavy braking with an antilock brake system (ABS). This is due to the ABS modulating the brake pressure to prevent wheel lockup. Technician B is incorrect because a spongy pedal during normal braking indicates a problem, such as air in the brake lines, and is not acceptable.

Question 7

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

Accepted Answer

A faulty wheel speed sensor is the most likely cause for the amber ABS brake warning light to be illuminated. This sensor is crucial for the ABS system to monitor the speed of each wheel and control braking pressure accordingly. Issues like leaks at the wheel caliper, restricted brake hoses, or excessive pedal free play would not directly trigger the ABS warning light, as they are more related to the hydraulic or mechanical aspects of the brake system rather than the ABS system's electronic monitoring and control functions.

Question 8

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?

Accepted Answer

Integral ABS systems are designed as part of the vehicle's primary hydraulic brake system, and they do not use a vacuum-type power brake booster. Nonintegral ABS systems are added to the vehicle's existing brake system and typically do not use a hydraulic-type power brake booster; instead, they work with the vehicle's existing brake system components.

Question 9

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?

Accepted Answer

Both statements are correct. A malfunction in the ABS system can indeed cause the control module to shut off or inhibit the system to prevent further damage or unsafe conditions. Similarly, a loss of hydraulic fluid or power booster pressure can disable the antilock brake system because both are essential for the system's operation.

Question 10

An accumulator is normally charged with ______.

Accepted Answer

Accumulators are typically charged with nitrogen because it is an inert gas, which means it does not react with other substances easily. This makes nitrogen safe for use in the high-pressure environments within accumulators.

Question 11

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?

Accepted Answer

Automatic Traction Control (ATC) systems are designed to prevent wheel spin during acceleration by automatically adjusting the power output to the wheels. These systems often work in conjunction with Antilock Brake Systems (ABS), contrary to Technician A's statement. Technician B is incorrect because ATC does not apply extra torque to a spinning wheel; instead, it typically reduces engine power or applies the brakes to the spinning wheel to prevent loss of traction.

Question 12

When the ABS is activated as a wheel begins to lock, the brake pedal will ______.

Accepted Answer

When the ABS (Anti-lock Braking System) is activated, the driver may feel a small bump followed by rapid pedal pulsations. This is a normal sensation indicating that the ABS is functioning properly to prevent the wheels from locking up during braking.

Question 13

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?

Accepted Answer

The answer of Technician A says the wheel speed sensor...

Question 14

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

Accepted Answer

The answer of Antilock brake systems can modulate the pressure...

Question 15

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

Accepted Answer

Pumping the brake pedal 25 times with the ignition off is the correct procedure to safely discharge the high-pressure accumulator in an ABS system before removing the master cylinder. This ensures that any stored pressure is safely released to prevent injury or damage during maintenance.

Question 16

A(n)______ stores hydraulic fluid to maintain pressure and provides residual pressure for power-assisted braking.

Accepted Answer

An accumulator in a hydraulic system stores hydraulic fluid under pressure, which is used to maintain pressure within the system and provide residual pressure for functions such as power-assisted braking.

Question 17

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?

Accepted Answer

Both technicians are correct. A loss of hydraulic fluid can disable the antilock brake system (ABS) because the system relies on hydraulic pressure to function. Similarly, a loss of power booster pressure can also disable the ABS since the power booster assists in providing the necessary force to the brakes, which is crucial for the ABS operation.

Question 18

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?

Accepted Answer

ABS systems are designed to prevent wheel lock-up during braking, which helps maintain directional stability, especially when turning. However, ABS may not always provide superior braking on loose snow, as it can increase stopping distances in such conditions.

Question 19

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

Accepted Answer

The accumulator in an antilock brake system (ABS) is a gas-filled pressure chamber that stores the hydraulic pressure needed for the ABS to function. This stored pressure can be rapidly deployed to the brake circuit to prevent wheel lockup during braking.

Question 20

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

Accepted Answer

The power steering pump is not a component of an antilock brake system (ABS); it is part of the vehicle's steering system. ABS typically includes components such as the master cylinder, solenoid valve body assembly, and wheel sensors to prevent the wheels from locking up during braking.

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