Deck 5: Introduction to Diagnostic Concepts and Diagnostic Equipment

Question 1

​ An AC voltage generating wheel speed sensor is being diagnosed. Technician A says the computer reacts to the frequency of the signal. Technician B says the computer reacts to how much voltage is produced. Who is correct?

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

Answer 1

A

Question 2

Memory codes are being discussed. Technician A says that when pulling memory DTC's, current condition does not matter. Technician B says most PCM's are programmed to erase a memory fault when a preset number of warm up cycles is reached without a repeated failure. Who is correct?

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

Answer 2

C

Question 3

Voltage drop is being discussed. Technician A says in an ideal circuit, most of the voltage drop should take place across the circuit. Technician B says in an ideal circuit, most of the voltage drop should take place across the load. Who is correct? ​

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

Answer 3

B

Question 4

Voltage drop testing is being discussed. Technician A says the power side of the circuit should be tested. Technician B says the ground side of the circuit should be tested. Who is correct?

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

Question 5

When capturing a current waveform from a motor, what is indicated if the waveform goes to "zero" twice per rotation? ​

A)​ An open winding
B)​ A shorted winding
C)​ Worn bushings or bearings
D)​ Current flow is reversing direction

Question 6

A technician is using a DVOM to measure a sensor's resistance. The DVOM is on a 20K scale. The display reads "4 . 651". Which value does this represent? ​

A)​ 4,651 ohms
B)​ 465.1 ohms
C)​ 4 . 651 ohms
D)​ 93,020 ohms (4 . 651 x 20,000)

Question 7

In order for its internal voltage reference regulator to continue to supply a 5 volt reference signal, the PCM must have at least _______ volts dropped across it.

A)14.1
B)12.6
C)9.6
D)5

Question 8

Functional tests are being discussed. Technician A says that with an on-demand test, the technician must determine pass/fail during the test. Technician B says that with an active command, the computer will determine pass/fail and set a DTC. Who is correct?

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

Question 9

Soft faults are being discussed. Technician A says a soft fault should be diagnosed before diagnosing any hard faults. Technician B says a soft fault is intermittent. Who is correct?

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

Question 10

Which statement is true concerning a breakout box?

A)​ It provides the same functionality as a scan tool.
B)​ It is normally used to reprogram the PCM.
C)​ It allows pinpoint tests of electronic system circuits without back-probing.
D)​Both A and B

Question 11

Technician A says that when back-probing an electrical connector with a T-pin, it is permissible to poke the T-pin through the wire as long as you do it carefully. Technician B says that it is permissible to back-probe an electrical connector on a 42-volt system as well as on a 14-volt system. Who is correct?

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

Question 12

Current ramping is a diagnostic procedure that is best suited for diagnosing problems associated with: ​

A)​ Circuitry
B)​ Switches
C)​ Load components
D)​ Input sensors

Question 13

All of the following statements concerning the use of an electrical schematic are true EXCEPT :

A)An electrical schematic can aid a technician in understanding how a system is designed to operate.
B)An electrical schematic is designed to be used only by automotive engineers and should never be used by an automotive field technician.
C)An electrical schematic can show circuit components, powers, grounds, computer input circuits, computer output circuits, and multiplexing data busses.
D)An electrical schematic can be used with a flow chart to maximize the technician's diagnostic potential.

Question 14

Checking for excessive circuit resistance is being discussed. Technician A says measuring voltage drop is the most accurate method of determining circuit resistance. Technician B says measuring resistance is the most accurate method. Who is correct? ​

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

Question 15

​ All of these statements are true of a scan tool EXCEPT

A)​ It is normally used to pinpoint test a circuit.
B)​ It communicates with the PCM using serial data (binary code).
C)​ It can be used to pull memory codes and/or initiate a performance self-test.
D)​ It can be used to look at data stream parameters concerning sensors and actuators.

Question 16

Which statement about on-demand tests is NOT true?

A)On demand tests can be made with the key on and the engine not running
B)On demand tests can be made with the engine running
C)Functional tests are performed during the KOER self-test
D)Functional tests are performed during the KOEO self-test

Question 17

​ A technician is capturing a current waveform for a load component on the positive side of a circuit. The current waveform shows higher-than-normal current flow. Which statement is true?

A)​ The windings within the component being tested may be shorted.
B)​ The waveform should be captured on the negative side of the circuit due to increased current flow on the positive side of the circuit.
C)​ A loose connection or other high resistance may exist within the controlling circuit.
D)​ An open may exist within the load component.

Question 18

Which of the following types of information is included in the data stream?

A)Memory codes
B)Fuel trim numbers
C)Input voltages
D)All of the above

Question 19

Two technicians are discussing a memory code that has been retrieved for a specific sensor. Technician A says that the sensor or the sensor's circuit may be at fault. Technician B says that the value that is being measured may be out of an acceptable range, although the sensor is operating properly. Who is correct?

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

Question 20

​ A voltage drop test is being performed. With the red lead placed on the ground terminal at the PCM and the black lead placed on the negative post of the battery, the meter reads 0.165 volt with the ignition key turned on, but the engine not running. Based on this reading, what is indicated?

A)​ The reference voltage to the sensors is low.
B)​ The computer is faulty.
C)​ The computer's ground circuit has excessive resistance.
D)​ This is a normal condition; it does not require any service.