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

Accepted Answer

The AC voltage generated by a wheel speed sensor is measured in hertz (frequency), not voltage. Therefore, only Technician A is correct.

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

Accepted Answer

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

Accepted Answer

In an ideal circuit, most of the voltage drop should take place across the load. This is because the load is where the energy is being consumed or utilized, so it should experience most of the voltage drop. Therefore, Technician B is correct. Technician A's statement is not necessarily true, as there can be other factors that cause voltage drop in a circuit, such as resistance or impedance.

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

Accepted Answer

Both technicians are correct. In order to determine if there is a voltage drop in a circuit, both the power and ground sides should be tested. A high voltage drop on the power side could indicate a problem with the power source, while a high voltage drop on the ground side could indicate a poor ground connection. Testing both sides will help identify the root cause of the voltage drop.

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

Accepted Answer

The answer of When capturing a current waveform from a...

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)

Accepted Answer

The display reading of "4 . 651" on a 20K scale means 4,651 ohms. The DVOM's scale indicates the maximum reading in thousands, so a reading directly corresponds to the actual resistance value in ohms when read directly off the display.

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

Accepted Answer

The PCM (Powertrain Control Module) needs a minimum voltage to operate correctly and maintain its internal functions, such as supplying a stable 5-volt reference signal. A voltage drop of at least 9.6 volts across it ensures that it has enough power to perform its tasks effectively, considering the electrical characteristics and requirements of automotive systems.

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

Accepted Answer

The answer of Functional tests are being discussed. Technician A...

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

Accepted Answer

Soft faults are indeed intermittent, meaning they occur sporadically rather than being constant.

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

Accepted Answer

A breakout box is a diagnostic tool used to test electronic systems. It allows technicians to access and test individual circuits without back-probing, which can damage delicate wiring. It is not used for reprogramming the PCM, and does not provide the same functionality as a scan tool. Therefore, the only true statement concerning a breakout box is that it allows pinpoint tests of electronic system circuits without back-probing.

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

Accepted Answer

Neither Technician A nor Technician B are correct. Back-probing with a T-pin should never be done by poking through the wire. It is also not permissible to back-probe an electrical connector on a 42-volt system due to the increased risk of shock and damage to components.

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

Accepted Answer

Current ramping is used to diagnose issues with load components by gradually increasing the current and observing the response, which helps identify problems like mechanical binding or electrical faults.

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.

Accepted Answer

Electrical schematics are valuable tools for both engineers and field technicians, helping them understand and troubleshoot electrical systems.

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

Accepted Answer

Technician A is correct. Measuring voltage drop is the most accurate method of determining circuit resistance as it takes into account the entire circuit, including connections and components that may contribute to resistance. Measuring resistance alone may not take into account these factors.

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.

Accepted Answer

A scan tool is not typically used to pinpoint test a circuit; it is used for diagnostics and communication with the vehicle's computer systems.

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

Accepted Answer

The statement "Functional tests are performed during the KOER self-test" is not true. Functional tests are actually performed during the KOEO (Key On Engine Off) self-test. Therefore, option D is the correct answer. Options A, B, and C are all true statements about on-demand tests.

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.

Accepted Answer

Shorted windings within a component can cause higher-than-normal current flow because the short reduces the resistance within the circuit, allowing more current to flow through the 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

Accepted Answer

The data stream includes all of the types of information listed - memory codes, fuel trim numbers, and input voltages. This information is transmitted by the vehicle's computer (ECU) and can be read by a diagnostic tool.

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)Both A and B
C)Neither A nor B

Accepted Answer

Both technicians could be correct. Technician A is suggesting a possible issue with the sensor or its circuit, which could cause erroneous readings. Technician B is suggesting that, even if the sensor and its circuit are working properly, the value being measured may be outside of an acceptable range. Therefore, the correct answer is 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.

Accepted Answer

A voltage drop above 0.1 volt across a ground circuit is an indication of excessive resistance. In this case, the high voltage drop indicates that the ground circuit for the PCM is faulty and needs to be inspected and repaired. Option A is incorrect because a low reference voltage would cause sensor malfunction, but it would not cause a voltage drop. Option B is incorrect because there is no evidence that the computer is faulty. Option D is incorrect because a voltage drop above 0.1 volt is not a normal condition and requires attention.

Quiz 5: Introduction to Diagnostic Concepts and Diagnostic Equipment

​ 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?

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?

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? ​

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?

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

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? ​

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.

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?

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?

Which statement is true concerning a breakout box?

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

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

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? ​

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

Which statement about on-demand tests is NOT true?

​ 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?

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

​ 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?

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?

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?

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

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?

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

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?

All of these statements are true of a scan tool EXCEPT

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 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?