On-board Diagnostics (Obd) Quiz - Know More About Vehicles
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On-board diagnostics (OBD) is an automotive term referring to a vehicle's self-diagnostic and reporting capability. OBD systems give the vehicle owner or repair technician access to the status of the various vehicle sub-systems. . The quiz below is set to help drivers and mechanics better understand how the system works. Take advantage and learn. Enjoy!
- 1.
Automotive emissions cause harm to all of these EXCEPT:
- A.
The air we breathe.
- B.
The environment.
- C.
Modern technology.
- D.
Human health.
Correct Answer
C. Modern technology.Explanation
Modern technology is not harmed by automotive emissions.Rate this question:
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- 2.
A vehicle is known to be out of compliance with clean air regulations whenever:
- A.
It flunks a safety inspection.
- B.
Its registration has expired.
- C.
A red light is illuminated on the instrument panel.
- D.
Its malfunction indicator lamp (MIL) is illuminated.
Correct Answer
D. Its malfunction indicator lamp (MIL) is illuminated.Explanation
An illuminated MIL would indicate an emissions related fault that would cause excessive, out of compliance emissions.Rate this question:
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- 3.
Which of these pollutants is caused by fuel or oil vapors?
- A.
Volatile organic compounds (VOCs)
- B.
Hydrocarbons (HCs)
- C.
Carbon monoxide (CO)
- D.
Particulate matter (PM)
Correct Answer
A. Volatile organic compounds (VOCs)Explanation
VOC's are the harmful emissions created by fuel AND oil.Rate this question:
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- 4.
Harmful tailpipe emissions include all of these EXCEPT:
- A.
Carbon monoxide (CO).
- B.
Hydrocarbons (HCs).
- C.
Particulate matter (PM).
- D.
Oxygen (O2).
Correct Answer
D. Oxygen (O2).Explanation
O2 is a naturally occurring, non-harmful emission.Rate this question:
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- 5.
Which of these has reduced the weight and expense of wire bundles in today's automobiles?
- A.
Aluminum wiring
- B.
Shared circuits
- C.
High-voltage circuits
- D.
Controller area networks
Correct Answer
D. Controller area networksExplanation
A CAN and its system of nodes and circuitry reduce the overall weight of vehicles.Rate this question:
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- 6.
In what year was on-board diagnostics II (OBDII) systems enacted nationwide?
- A.
1973
- B.
1981
- C.
1975
- D.
1996
Correct Answer
D. 1996Explanation
1996 is the year of OBDII implementation.Rate this question:
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- 7.
Which of these provides constant yet simplified interconnectivity between on-board vehicle modules?
- A.
Discreet wiring
- B.
A controlled area network bus (CAN-bus)
- C.
A scan tool
- D.
A personal computer (PC)
Correct Answer
B. A controlled area network bus (CAN-bus)Explanation
Constant binary code is shared between control modules.Rate this question:
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- 8.
A diagnostic trouble code (DTC) indicates that a vehicle has experienced all of these EXCEPT:
- A.
An emissions related fault.
- B.
A broken “hard part.”
- C.
A broken “hard part.”
- D.
An illuminated malfunction indicator lamp (MIL).
Correct Answer
B. A broken “hard part.”Explanation
A DTC will get you headed in the correct direction, but a technician must confirm that a part is broken before replacing it.Rate this question:
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- 9.
Engine related freeze-frame data can be accessed from the vehicle's:
- A.
Electronic brake control module (EBCM).
- B.
Transmission control module (TCM).
- C.
Power train control module (PCM).
- D.
Body control module (BCM).
Correct Answer
C. Power train control module (PCM).Explanation
The PCM or ECM are responsible for monitoring and storing engine related processed and faults.Rate this question:
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- 10.
Continuous monitors are run for systems that could:
- A.
Contribute to major emissions failures.
- B.
Cause a safety related problem.
- C.
Cause an inconvenience for the driver.
- D.
Cause other systems to fail.
Correct Answer
A. Contribute to major emissions failures.Explanation
Individual monitors are continuous and are subsystems of ECM/PCM processes.Rate this question:
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- 11.
A drive cycle includes all of these EXCEPT:
- A.
Vehicle start-up.
- B.
Vehicle acceleration.
- C.
Vehicle cruise.
- D.
Vehicle cold soak.
Correct Answer
D. Vehicle cold soak.Explanation
Cold soak is when an engine sits without running, until it is as cold as the ambient temperature.Rate this question:
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- 12.
State-run emission inspection stations in the United States will sometimes allow a vehicle to pass an emission inspection under any of these situations EXCEPT:
- A.
A monitor has run and failed.
- B.
A monitor has run and is pending.
- C.
One monitor has not run.
- D.
Two monitors have not run.
Correct Answer
A. A monitor has run and failed.Explanation
Some States may allow a vehicle with an emissions monitor that has run and not failed, a pass on state regulated emissions.Rate this question:
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- 13.
Which of these is a device able to electronically communicate with and extract data from the vehicle's one or more on-board computers?
- A.
An oscilloscope
- B.
A scanner
- C.
A graphing calculator
- D.
A power probe
Correct Answer
B. A scannerExplanation
A scanner links to a vehicle and gets important, DTC/MIL related information.Rate this question:
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- 14.
Tech A says that it is possible for a vehicle to have one fault that causes yet another fault to set a code. Tech B says that the test light, an analog voltmeter, and a logic probe are worthwhile diagnostic tools. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
A. Tech AExplanation
If certain parameters are so out of whack. it may lead to multiple codes setting. An analog voltmeter is not something that is commonly used in the automotive trade.Rate this question:
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- 15.
On-board diagnostics II (OBDII) data are retrieved by connecting a scan tool to the:
- A.
Malfunction indicator lamp (MIL).
- B.
Data link connector (DLC).
- C.
Diagnostic trouble code (DTC).
- D.
Power train control module (PCM).
Correct Answer
B. Data link connector (DLC).Explanation
The DLC is the interface between the vehicle and the scan tool.Rate this question:
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- 16.
Tech A says that the on-board diagnostics II (OBDII) system is designed to set fault codes if the vehicle exceeds the limits programmed within the vehicle system. Tech B says that the EPA Federal Test Procedure pass and fail points are the same for every vehicle. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
A. Tech AExplanation
Conditions that are outside preprogrammed values causes the DTC/MIL to illuminate. The test procedure for every vehicle is not the same.Rate this question:
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- 17.
To ensure that a vehicle malfunction is identified and repaired correctly, always follow
- A.
Aftermarket service manuals.
- B.
Original equipment manufacturer (OEM) diagnostic flow charts.
- C.
Aftermarket training manuals.
- D.
OEM owners' manuals.
Correct Answer
B. Original equipment manufacturer (OEM) diagnostic flow charts.Explanation
The best, most accurate and up-to-date information for servicing vehicles is found in the OEM diagnostic flow charts.Rate this question:
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- 18.
When it comes to troubleshooting an on-board diagnostic (OBD) code, the tech's best tools include all of these EXCEPT:
- A.
A test light.
- B.
A digital volt-ohmmeter (DVOM).
- C.
A lab scope.
- D.
A scan tool.
Correct Answer
A. A test light.Explanation
A test light does not give us sufficient information for these sophisticated concerns or issues.Rate this question:
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- 19.
Which of the following types of data helps a tech to determine the actual conditions under which a fault code is set?
- A.
Technical service bulletin (TSB) data
- B.
Diagnostic trouble code (DTC) data
- C.
Service manual data
- D.
Freeze-frame data
Correct Answer
D. Freeze-frame dataExplanation
Freeze frame data are the conditions that were occurring when the DTC was set.Rate this question:
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- 20.
A fault code that begins with the letter “B” would MOST likely address a fault in the:
- A.
Ignition system.
- B.
Exhaust system..
- C.
Taillight circuit.
- D.
Transmission
Correct Answer
C. Taillight circuit.Explanation
The "B" in a MIL indicates that the concern is a body related fault.Rate this question:
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- 21.
A fault code that begins with the letter “P” would MOST likely address a fault in the:
- A.
Exhaust system.
- B.
Power door lock wiring.
- C.
HVAC system.
- D.
Interior lighting system.
Correct Answer
A. Exhaust system.Explanation
The "P" in the DTC indicates a fault in the powertrain system.Rate this question:
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- 22.
Fault codes on today's vehicles are categorized by vehicle:
- A.
System.
- B.
Year.
- C.
Make.
- D.
Model.
Correct Answer
A. System.Explanation
In contemporary vehicles, DTC's are categorized by system.Rate this question:
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- 23.
On-board diagnostic (OBD) systems help the service tech do all of these EXCEPT:
- A.
Work more efficiently.
- B.
Determine exactly where faults exist.
- C.
Take the guesswork out of diagnosing vehicle problems.
- D.
Access data for today's sophisticated vehicles.
Correct Answer
B. Determine exactly where faults exist.Explanation
An accomplished technician still needs to run tests, and confirm any fault the vehicle "thinks" it may have.Rate this question:
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- 24.
Tech A says that the original equipment manufacturer (OEM) offer scan tools to service their specific line of vehicles. Tech B says that scan tools supplied by aftermarket tool and equipment providers usually provide greater functionality. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
A. Tech AExplanation
All OEM offer their own, proprietary scan tools that most often offer the greatest functionality for advanced testing and inspecting of DTC related concerns.Rate this question:
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- 25.
Never jump battery or power supply voltages to an actuator while it is connected to its:
- A.
Control circuit.
- B.
Mother board.
- C.
Mechanical linkage.
- D.
Driven component.
Correct Answer
A. Control circuit.Explanation
Leaving a controller hooked up when jumping to power to operate an actuator will allow the current to potentially also go into the controller.Rate this question:
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- 26.
Tech A says that many actuators operate on voltages supplied by the system computer. Tech B says that actuators may operate on at voltages other than battery voltage. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
C. Both Techs A and BExplanation
Actuators are not only driver commanded. A controller may also operate actuators. These circuits, at times, may operate on voltages other than battery voltage.Rate this question:
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- 27.
Which of these is the best place to start gathering information and planning a diagnostic pathway based on suspected systems and components?
- A.
The owner's manual
- B.
Diagnostic trouble codes (DTCs) and customer information
- C.
The service manual
- D.
Technical service bulletins
Correct Answer
B. Diagnostic trouble codes (DTCs) and customer informationExplanation
Always start with customer experiences, reading DTC's, and driving the vehicle yourself to confirm these experiences.Rate this question:
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- 28.
Tech A says that a graphing multimeter may be used to verify signals going to and from electrical and electronic components. Tech B says that digital storage oscilloscope may be used to verify signals going to and from electrical and electronic components. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
C. Both Techs A and BExplanation
Both of the listed tools can be used to verify electrical signals, but the oscilloscope is a much more sophisticated piece of diagnostic equipment.Rate this question:
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- 29.
Electrical circuits in the on-board diagnostics (OBD) system are being diagnosed. Tech A says that it's important to check for voltage drops on the power side of the circuit. Tech B says that it's important to check for voltage drops at the circuit ground connections. Who is correct?
- A.
Tech A
- B.
Tech B
- C.
Both Techs A and B
- D.
Neither Tech A nor B
Correct Answer
C. Both Techs A and BExplanation
The voltage drop test is one of the most important electrical tests, and can be performed on any complete circuit.Rate this question:
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- 30.
A scan tool detects a communications fault in the controlled area network bus (CAN-bus). Which of these diagnostic trouble codes (DTCs) would MOST likely be stored?
- A.
P0402
- B.
U0021
- C.
B0092
- D.
C0035
Correct Answer
B. U0021Explanation
"U" is the designation for communication faults.Rate this question:
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Mar 22, 2023Quiz Edited by
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Dec 08, 2014Quiz Created by
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