Question 1

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?

Accepted Answer

An integral-type ABS system uses accumulator pressure for both power brake assist and to operate the rear brakes.

Question 2

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?

Accepted Answer

Both technicians are correct. When the front wheels are locked, steering ability is indeed reduced because the vehicle can no longer change direction as the wheels are not able to rotate and respond to steering inputs. When the rear wheels are locked, the stability of the vehicle is compromised, making it more prone to skidding or spinning, especially in high-speed or sharp turning situations.

Question 3

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?

Accepted Answer

Technician A is correct because wheel speed sensor data is shared across the CAN network for various systems like ABS and traction control. Technician B is also correct because traditional wheel speed sensors are often AC generator-type sensors, also known as variable reluctance sensors.

Question 4

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?

Accepted Answer

Both technicians are correct. Understeer is indeed a condition where the vehicle is slow to respond to steering inputs, typically pushing straight ahead in a corner instead of following the intended path. Oversteer is when the rear wheels lose grip before the front wheels, potentially causing the rear of the vehicle to swing out or "fishtail," as described by Technician B.

Question 5

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

Accepted Answer

Proportioning valves are not part of the hydraulic control unit in an ABS system. They are used to adjust the pressure to the rear brakes to prevent them from locking up before the front brakes. The hydraulic control unit typically includes solenoid valves, a pump and electric motor, and fluid accumulators to manage brake fluid pressure during ABS operation.

Question 6

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?

Accepted Answer

Technician A is correct because ATC (Automatic Traction Control) systems indeed use the vehicle's ABS system to control wheel spin, which requires a pump to generate hydraulic pressure and an accumulator to store it. Technician B is incorrect because pulse rings and wheel-speed sensors for ATC systems are typically located at the wheels, not inside the transmission, and are the same or similar to those used in ABS systems.

Question 7

Which of the following is not a location for the toothed ring (toner ring)?

Accepted Answer

The toothed ring, also known as a tone ring, is typically found on the axle shaft, differential carrier, and wheel hub, where it is used in conjunction with wheel speed sensors for ABS and traction control systems. It is not found on a modulator unit, which is related to the control aspect of these systems rather than the sensing of wheel speed.

Question 8

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

Accepted Answer

Electronic Stability Control (ESC) systems require input from multiple sensors to accurately assess and adjust a vehicle's stability. This includes wheel speed sensors, steering angle sensors, lateral-acceleration sensors, and yaw sensors. Each of these sensors provides critical information about the vehicle's movement and orientation, allowing the ESC system to make precise adjustments to maintain stability.

Question 9

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?

Accepted Answer

Technician B is correct because DOT 3, a glycol-based fluid, is the recommended brake fluid for most ABS systems, not silicone-based fluids. Silicone-based fluids (DOT 5) are not typically recommended for ABS systems due to their different properties, such as air absorption and compressibility, which can affect the system's performance.

Question 10

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?

Accepted Answer

Technician A is correct because if the number of teeth on the toner ring of the new axle differs from the old one, it can cause the ABS system to malfunction, triggering the ABS warning light. The ABS system relies on the toner ring to monitor wheel speed; a mismatch in the number of teeth can lead to incorrect readings. Technician B's suggestion of an ABS speed sensor relearn procedure might not address the root cause if the issue is with the toner ring's tooth count.

Question 11

An accumulator unit is typically found on vehicles with _____.

Accepted Answer

An accumulator unit is typically found on vehicles with hydraulically assisted power brakes, where it stores hydraulic pressure to ensure consistent brake performance.

Question 12

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?

Accepted Answer

Technician B is correct because the proper way to use ABS (Anti-lock Braking System) is to apply steady pressure to the brake pedal during hard braking. Pumping the brake pedal, as Technician A suggests, is unnecessary with ABS and can actually reduce the system's effectiveness.

Question 13

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 increase traction. Who is correc t?

Accepted Answer

Technician A is correct because ESC applies the brake at the inside rear wheel to help correct an understeer condition by creating a yaw moment that helps the vehicle turn more effectively. Technician B is incorrect because ESC is primarily designed to maintain vehicle stability rather than increase traction.

Question 14

If the brake fluid level is below minimum in an ABS, which warning lamp will turn on?

Accepted Answer

The answer of If the brake fluid level is below...

Question 15

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?

Accepted Answer

The solenoid valves inside the modulator unit of an Anti-lock Braking System (ABS) are used both to decrease and increase brake pressure as needed to prevent wheel lockup during braking, making both Technician A and Technician B correct.

Question 16

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

Accepted Answer

The answer of Technician A says ABS wheel speed sensors...

Question 17

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?

Accepted Answer

Technician A is correct because a three-channel ABS system typically has individual hydraulic circuits for each of the front wheels and a single circuit for both rear wheels, aligning with the description given. Technician B is incorrect because a three-channel ABS system does not have four sets of solenoids; it would have three channels to control, corresponding to the three hydraulic circuits mentioned.

Question 18

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

Accepted Answer

The yaw rate sensor and lateral accelerometer are typically located in the center of the vehicle to accurately measure the vehicle's movements and ensure balanced detection of lateral forces and rotational motion around the vertical axis.

Question 19

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

Accepted Answer

The answer of When activated, the dump valve sends hydraulic...

Question 20

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

Accepted Answer

The answer of The function of the pressure switch in...

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

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?