Deck 46: Electronics and Computer Systems Service

Question 1

16)A digital multimeter (DMM) is the instrument used to measure electricity in electronic circuits. A(n) ____________________ must be used to perform tests on these systems.

Answer 1

high-impedance voltmeter,high impedance voltmeter

Question 2

3)A scan tool is a portable computer that reads data from the on-board computer.

Answer 2

True

Question 3

7)Which of the following is LEAST-Likely a criteria found on the scan tool?

A) Engine rpm
B) Warm-up status
C) Forward bias
D) Vehicle speed

Answer 3

C

Question 4

10)A defective or misadjusted TPS can send an excessive voltage to the computer that is interpreted as ____.

A) CKP
B) WOT
C) DLC
D) MAF

Question 5

5)Active sensors do not generate their own signal.

Question 6

15)While having a discussion, Technician A says that adaptive memory learns faster if the computer's memory is erased first. Technician B says that if memory is erased, it will take longer for the system to adapt. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 7

13)The part MOST-Likely used to compare the reading inside the engine to an absolute pressure calibration in the computer is the:

A) MAP sensor
B) BARO sensor
C) TPS sensor
D) Plenum

Question 8

11)The sensor that is MOST-Likely a low authority sensor is:

A) oxygen sensor
B) mass airflow sensor
C) throttle position sensor
D) intake air temperature sensor

Question 9

19)OBD II scan tools are powered through the ____________________ and do not require an external power source.

Question 10

18)A(n) ____________________ in the service library provides a step-by-step diagnostic procedure to follow when troubleshooting hard-fault problems

Question 11

14)Which of the following is LEAST-Likely an actuator?

A) Solenoid
B) Fuel Injector
C) Armature
D) Stepper motor

Question 12

8)While having a discussion, Technician A says that an ohmmeter should be used to test an O₂ sensor. Technician B says that you should not use an ohmmeter to test an O₂ sensor. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 13

20)An ECT sensor is a thermistor; it will have lower resistance as coolant temperature rises. This is called a(n) ____________________ thermistor.

Question 14

1)To check a meter to see if it has high impedance, turn the selector to the direct current (DC) volts position.

Question 15

17)To check a meter to see if it has high impedance, turn the selector to the ____________________ volts position.

Question 16

12)All of the following statements are true EXCEPT:

A) basic fuel delivery to the engine is determined by signals from the MAP sensor (load), CKP (rpm), and ECT (temperature).
B) a MAP sensor produces a voltage that drops as vacuum becomes higher.
C) barometric pressure (BARO) sensors are used on some systems to monitor changes in the weather or altitude.
D) load sensors include MAP, vacuum, and TPS.

Question 17

9)An oscilloscope capable of displaying four waveforms is called a ____.

A) four-channel scope
B) quadroscope
C) bidirectional scope
D) waveform scope

Question 18

2)If the charging system voltage is hovering near 11.6 volts, stepping on the brakes will turn on the brake lights, dropping the voltage further and causing the computer to raise engine idle.

Question 19

6)All of the following statements are true EXCEPT:

A) to quickly evaluate compression, listen during cranking for an even rhythm and then for a smooth idle.
B) an EGR valve is open at idle during normal operation.
C) when an EGR valve is opened by a vacuum pump, the engine should stumble and run roughly.
D) a vacuum gauge is easy to connect and can be used to qualify engine condition.

Question 20

4)Bidirectional means that the scan tool can read data but cannot give commands to the computer.

Question 21

23)What three things must occur in order for a computer system to go into a closed loop?

Question 22

21)What are the advantages of DMMs?

Question 23

22)What is the difference between a hard fault and an intermittent fault?

Question 24

24)What points should you bear in mind when using a scan tool to diagnose driveability problems while watching fuel trim?

Question 25

25)Under what circumstances would a no-start condition occur?