Chapter 10 (only 29 questions in this chapter)

Question 1

1) Describe the general operation of the magnetic reluctance (PM) wheel speed sensor.

Answer 1

The Reluctor rotates has permanent magnets imbedded in it and as it rotates past a coil of copper wire to induces an electrical current that is read as a signal

Question 2

2) Describe the general operation of the magneto resistive wheel sensor.

Answer 2

The magnetoresistive sensor produces a digital signal and has its own power supply. The amplitude of the signal is constant, which means the voltage level does not change with wheel speed, only the frequency. A magnetic reluctance sensor can produce a readable signal even with the wheel stopped.

Question 3

3) Explain the job of wheel speed sensor in the ABS system.

Answer 3

The tire speed sensor measures the rotational speed of the tire and if the tire is breaking too fast and the computer detects a skid could potentially occur the computer allows a decrease in pressure to the master cylinder. This process can happen several times per second until the vehicle comes to a stop.

Question 4

4) Describe the construction difference between the integrate ABS and the nonintegrated ABS.

Answer 4

integrated systems - have a hydraulic brake booster, a master cylinder, and an ABS computer referred to as an EBCM all built into one unit
The nonintegrated system - was also called an “add-on” system, because it used a conventional vacuum booster and basic brake system with a separate hydraulic modulator. The nonintegrated ABS system was a benefit to all concerned, from the manufacturer to

Question 5

5) Describe the difference in the DBC-7 without TCS and the DBC-7 with TCS.

Answer 5

(no answer)

Question 6

6) What can the Bosh ABS 9.0unit control as far as braking/stability control enhancements?

Answer 6

The Bosch ABS 9.0 is a four-channel ABS system. This system is capable of handling ABS, TCS, VSC, Hill start assist, DRP and brake assist.

Question 7

7) Explain why some ABS systems no longer use proportioning valves

Answer 7

In fact, ABS pressure control is more precise than a hydraulic or mechanical metering valve or a proportioning valve. Since antilock brakes became standard, engineers had the opportunity to eliminate the old valves and replace them with a computer-controlled system. Very few systems still use proportioning and metering valves in addition to the ABS function. This ensures that, in case of an ABS failure, the vehicle would still have safe braking.

Question 8

8) What is the advantage of vehicle networking?

Answer 8

The advantage of networking is the elimination of redundant sensors and the accompanying wiring. An example of this is that several years ago, vehicles had a temperature sensor to control the engine cooling fan, a temperature sensor for the warning lamp in the instrument cluster, and finally, a temperature sensor for the ECM. Now, the engine coolant temperature (ECT) for the ECM takes care of all three

Question 9

9) What is the first thing the traction control can do to help eliminate positive wheel spin?

Answer 9

The traction control applies the brake to stop the spinning tire from positive wheel spin.

Question 10

If the EBCM senses wheel slip when the brakes are not applied, its first step is to request the PCM to reduce______________ _______________.

Answer 10

Engine Power

Question 11

The DBC-7 operates on _______________ volts instead of _______________ volts.

Answer 11

7 instead of 5

Question 12

High-speed CAN, which is needed for “real time” computer interaction is rated at _______________

Answer 12

1Mb/sec

Question 13

A slow wheel as monitored by the wheel speed sensor will produce a _______________frequency signal, whereas a faster wheel will cause a com- paratively _______________ frequency.

Answer 13

lower, higher

Question 14

The _______________ replaces the standard hydraulic proportioning valve found on many older vehicles.

Answer 14

DRP - direct proportioning valve

Question 15

The magnetoresistive sensor produces a _______________ signal and has its own power supply. The amplitude of the signal is constant.

Answer 15

digital

Question 16

Magnetic lines of force are called _______________ _______________.

Answer 16

flux lines

Question 17

The Continental Teves Mk60/Mk70 system has hydraulic brake assist that increases pressure to the brakes whenever a _______________ _______________ is detected through the brake pedal sensor.

Answer 17

panic stop

Question 18

The hydraulic pump for the Bosch 9.0 system has _______________ pistons instead of two that were used on earlier systems.

Answer 18

nine

Question 19

The TCS is designed to control wheel spin or _______________ wheel slip.

Answer 19

postive

Question 20

Technician A says with digital signals only the frequency changes. Technician B says an analog voltage signal is infinitely variable; in other words, it flows smoothly as it changes voltage levels. Who is correct?

Answer 20

Both

Question 21

Sensors are being discussed. Technician A says that sensors are used to measure some sort of physical action and change it to an electrical sig- nal. Technician B says that the simplest sensors are often on–off switches. Who is correct?

Answer 21

A only

Question 22

echnician A says that an actuator converts mechanical action to electric energy. Technician B says that an actuator uses electric current to per- form a mechanical action. Who is correct?

Answer 22

B only

Question 23

Actuators and sensors are being discussed. Technician A says that a too low current may mean that an actuator or sensor is not function- ing properly. Technician B says that the controller cannot monitor actuator and sensor operation electrically. Who is correct?

Answer 23

Neither

Question 24

Command signals are being discussed. Technician A says that automotive controllers (computers) are simple compared to those used at work or school. Technician B says that most auto- motive computers work without sharing informa- tion with other computers on the network. Who is correct?

Answer 24

Neither

Question 25

While discussing TCS as an outgrowth of four- wheel four-channel ABS, Technician A says most of the same components are used in both sys- tems. Technician B says the TCS also interfaces with the engine (PCM) and transmission (TCM) control modules to request that specific actions be taken. Who is correct?

Answer 25

both

Question 26

Technician A says that an integrated ABS unit has many serviceable parts. Technician B says that the nonintegrated ABS has many serviceable parts. Who is correct?

Answer 26

B only

Question 27

There are several different names in use for the ABS controller. All of the following names have
been used except:

Answer 27

A. BACU

Question 28

While discussing ABS brakes, Technician A says ABS is excellent in directional stability. Technician B says ABS is excellent in directional control. Who is correct?

Answer 28

Both

Question 29

Technician A says that PM generator (variable reluctance) sensor produces a digital signal. Technician B says that a PM generator used an elec- tromagnet as part of the sensor. Who is correct?

Answer 29

Neither