Deck 19: On Board Diagnostics

Question 1

The preliminary standard developed by CARB and used before OBD-II was called _____________.

A)engine manufacturer's diagnostic (EMD) systems
B)OBD-II (On-Board Diagnostics Second Design)
C)OBDI (On-Board Diagnostics)
D)CAN (controller area network)

Answer 1

C

Question 2

Two technicians are discussing the purpose of OBD-II compliant systems for automotive diesel engines. Technician A says that an OBD-II compliant system is designed to identify or self-diagnose emission-related faults and report fault codes. Technician B says the OBD-II rules are set up to enable drivers to have emissions problems repaired quickly and easily. Who is correct?

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

Answer 2

C

Question 3

How many wires will transmit and receive signal data for the CAN engine/powertrain network on the diagnostic datalink connector (DLC) for an OBD-II compliant vehicle?

A)Only 1.
B)Two.
C)Four.
D)Five.

Answer 3

B

Question 4

An enhanced OBD-II code will be indicated by which position in the SAE code structure?

A)last digit.
B)last two digits.
C)first two digits.
D)second digit.

Question 5

Technician A says that any DTC will immediately illuminate the MIL in the driver's view the moment one is detected. Technician B says that all OBD-II DTCs will take several trips to confirm that a fault is active before switching on the MIL. Who is correct?

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

Question 6

Technician A says that a pending fault will not have a DTC that can be retrieved by a scanner or electronic service tool. Technician B says a pending fault will never have freeze-frame data associated with it. Who is correct?

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

Question 7

While two technicians are examining the many pairs of wires connected to an OBD-II DLC, Technician A says that all the wires are needed to retrieve fault does from the OBD system. Technician B says that only a pair of CAN wires are necessary to retrieve OBD-II fault codes. Who is correct?

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

Question 8

Consider a 2018 OBD-II-compliant and Tier 3-compliant diesel engine. What factor or threshold of excess emissions is typically required to illuminate the MIL when a fault in the diesel particulate filter (DPF) is detected?

A)One and a half times FTP emissions standards.
B)Two times FTP emissions standards.
C)Three times FTP emissions standards.
D)There is no FTP multiplier for Tier 3-compliant diesel engines.

Question 9

Which OBD-II monitor tracks electrical circuits operating engine components that can fail and cause measurable emissions?

A)functional monitor.
B)continuous monitor.
C)comprehensive component monitor (CCM).
D)threshold monitor.

Question 10

If a coolant temperature sensor shorted to ground, which emissions system monitor would first detect the fault?

A)cooling system monitor.
B)rationality monitor.
C)comprehensive component monitor (CCM).
D)network communication monitor.

Question 11

Which of the following is a critical enabling condition for a 2018 misfire monitor?

A)The engine must be at idle.
B)The engine cannot have a mechanical defect.
C)The fuel tank must be above ¼ tank.
D)The engine has to operate above idle speed.

Question 12

Technician A says that if all the sensors and components of the aftertreatment system are removed, the OBD-II system will not be able to detect faults in the absence of electrical signals. Technician B says that the comprehensive component monitor (CCM) will set emission-related fault codes. Who is correct?

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

Question 13

Technician A says that only the fuel system monitor will set DTCs for a misfiring injector. Technician says that the fuel system monitor and misfire monitor will set multiple DTCs. Who is correct?

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

Question 14

Before returning a vehicle to the customer after repairing the cause of the MIL being illuminated, the technicians should ______________.

A)erase all codes and road test the vehicle until a readiness code is set
B)rescan the vehicle for codes after road testing the vehicle
C)run the emission monitor associated with the fault
D)check for only active codes after road testing the vehicle

Question 15

Which emissions system monitor will detect incorrect injection timing?

A)Injection timing monitor.
B)Comprehensive component monitor (CCM).
C)Rationality monitor.
D)Fuel system monitor.

Question 16

Which of the following changes will take place when a manufacturer updates a software calibration and a technician uploads or flashes the vehicle with the new calibration?

A)All monitors will be set to ready.
B)The calibration identification number will change.
C)The calibration identification (CAL ID) and calibration verification numbers (CVNs) will both change.
D)The CAL ID number will change and CVNs will remain the same.

Question 17

Technician A says that some emission-related DTCs will cause engine power derate to encourage a driver to have the emissions system repaired. Technician B says that most diesel engine OBD DTCs will derate engine power. Who is correct?

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

Question 18

Technician A says that the OBD system on a diesel is continuously judging all major emissions systems for faults. Technician B says that some emissions monitors do not run every drive cycle and take time to correctly judge emissions system operation. Who is correct?

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

Question 19

While two technicians are discussing what to do to prepare a vehicle to pass an OBD-II emissions system inspection with an noncontinuous monitor DTC that causes the MIL to illuminate, Technician A says that the problem would need to be repaired and that the monitors all need to successfully run to pass. Technician B says that just the code could be erased before sending the customer to the inspection. The fault could be fixed after the vehicle has passed the OBD-II inspection test. Who is correct?

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

Question 20

Technician A says that anytime the tailpipe NOx sensor reads more than a few parts per million of NOx, DTCs will switch the MIL on. Technician B says that model predictive control (MPC) will always make adjustments to the engine to correct the fault. Who is correct?

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

Question 21

Two technicians are discussing the purpose of OBD-II compliant systems for automotive diesel engines. Technician A says that an OBD-II compliant system is designed to identify or self-diagnose emission-related faults and report fault codes. Technician B says the OBD-II rules are set up to enable drivers to have emissions problems repaired quickly and easily. Who is correct?

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

Question 22

A diagnostic approach using OBD (on-board diagnostic) data is unlike a symptom-based diagnostic strategy-a problem is identified based on a:

A)cause"
B)complaint"
C)condition
D)problem"

Question 23

Which of these OBD (on-board diagnostic) codes are also vital for technicians to validate before returning a vehicle to the customer?

A)System readiness codes"
B)System fault codes"
C)Diagnostic trouble codes
D)Fault readiness codes"

Question 24

Technician A says that in North America, only the EPA (Environmental Protection Agency) outlines standards for OBD (on-board diagnostic) system operation for vehicles operated over the road. Technician B says that the European On-Board Diagnostics (EOBD) and OBD legislation and regulations should not be confused with enhanced OBD codes, which refer to manufacturer-specific or proprietary diagnostic codes. Who is right?

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

Question 25

What attached to the body near the engine compartment designates vehicles that comply with either federal EPA (Environmental Protection Agency) or California Air Resource Board (CARB) emission standards?

A)EPA/CARB label"
B)Emission decal label"
C)Monroney label
D)Emission systems Label"

Question 26

Technical standards for OBD (on-board diagnostic) are developed by the

A)EPA (Environmental Protection Agency)"
B)CARB (California Air Resource Board)"
C)OEM (original equipment manufacturer)
D)SAE (Society of Automotive Engineers)"

Question 27

From its inception, an essential function of the OBD (on-board diagnostic) system was its use as a tool for emissions inspection and maintenance programs, often called:

A)emission tests"
B)SMOG tests"
C)I/M (inspection maintenance) tests
D)Federal Test Procedures (FTP)"

Question 28

A CARB (California Air Resource Board)-certified Tier 2 bin 5 vehicle has a Federal Test Procedures (FTP) protocol limiting NOx to no more than:

A)0.05 grams/mile"
B)0.07 grams/mile"
C)0.10 grams/mile
D)0.12 grams/mile"

Question 29

An enhanced OBD-II code will be indicated by which position in the SAE code structure?

A)last digit."
B)last two digits."
C)first two digits.
D)second digit."

Question 30

Technician A says that a pending fault will not have a DTC that can be retrieved by a scanner or electronic service tool. Technician B says a pending fault will never have freeze-frame data associated with it. Who is correct?

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

Question 31

Which of the following is a set of prescribed driving cycles performed on a chassis dynamometer which should not to be confused with emissions limits?

A)FTP (federal test procedures)"
B)MI (malfunction indicators)"
C)DTC (diagnostic trouble codes)
D)Blink codes"

Question 32

Which of the following is NOT included in the OBDII (On Board Diagnostic Generation II) systems for diesel engines?

A)Standardization of a 12-pin diagnostic connector link (DLC) in the driver area"
B)Standardization of SAE generic emission-related fault codes across all manufacturers"
C)Standardized network communication at the DLC
D)Mandatory reporting of standardized emission-related data at the DLC"

Question 33

The SAE standard J-1962 specifies that the D-shaped DLC must contain ---___ terminals.

A)6"
B)9"
C)12
D)16"

Question 34

The CAN module messages are transmitted over a pair of wires called a:

A)wiring bus"
B)bar bus"
C)data bus
D)information bus"

Question 35

Which of the following is the latest network communication protocol, which has an international standard described in ISO 14229-1:

A)SAE J1850 VPW (variable pulse width)"
B)LAN (Local Area Network)"
C)SAE J1850 PWM (pulse-width modulation)
D)UDS (Unified Diagnostic Service)"

Question 36

Which of the following narrow down the location of a fault or abnormal system condition but require further testing to differentiate between several possible root causes and verify the root cause?

A)FTP (federal test procedures)"
B)MI (malfunction indicators)"
C)DTC (diagnostic trouble codes)
D)Blink codes"

Question 37

If a coolant temperature sensor shorted to ground, which emissions system monitor would first detect the fault?

A)cooling system monitor."
B)rationality monitor."
C)comprehensive component monitor (CCM).
D)network communication monitor."

Question 38

Technician A says that if all the sensors and components of the aftertreatment system are removed, the OBD-II system will not be able to detect faults in the absence of electrical signals. Technician B says that the comprehensive component monitor (CCM) will set emission-related fault codes. Who is correct?

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

Question 39

The ________ data that the ECM (engine control module) stores will provide a snapshot of the engine operating conditions at the moment when the DTC (diagnostic trouble code) was confirmed by the OBD system.

A)freeze-frame"
B)control frame"
C)service information
D)service record"

Question 40

Leaving the filler cap off a diesel fuel tank is an indication of:

A)a major emission monitor associated with it"
B)there not being a major emission monitor associated with it"
C)a minor emission monitor associated with it
D)a connection to a major emission monitor"

Question 41

Which OBDII (On Board Diagnostics Generation II) monitor must make sure that there is adequate airflow to support combustion?

A)Fuel system monitor"
B)Misfire monitoring"
C)EGR system monitoring
D)Boost pressure control systems"

Question 42

All of these are possible monitor criteria for cold-start emissions, EXCEPT:

A)Glow plugs or intake heater on time"
B)Glow plugs and intake heater current flow"
C)Glow plugs and intake air heaters enabled
D)Glow plugs and intake air heaters disabled"

Question 43

Which of the following sense proper thermostat functioning?

A)Thermostat functioning sensor"
B)Engine coolant temperature sensor"
C)Cooling fan sensor
D)Engine dash temperature gauge"

Question 44

Technician A says that the comprehensive component monitor measures circuit voltage. Technician B says that the comprehensive component monitor gets its name from the vast number of circuits in it. Who is right?

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

Question 45

Before returning a vehicle to the customer after repairing the cause of the MIL being illuminated, the technicians should ______________.

A)erase all codes and road test the vehicle until a readiness code is set"
B)rescan the vehicle for codes after road testing the vehicle"
C)run the emission monitor associated with the fault
D)check for only active codes after road testing the vehicle"

Question 46

Which of the following changes will take place when a manufacturer updates a software calibration and a technician uploads or flashes the vehicle with the new calibration?

A)All monitors will be set to ready."
B)The calibration identification number will change."
C)The calibration identification (CAL ID) and calibration verification numbers (CVNs) will both change.
D)The CAL ID number will change and CVNs will remain the same."

Question 47

Technician A says that the OBD system on a diesel is continuously judging all major emissions systems for faults. Technician B says that some emissions monitors do not run every drive cycle and take time to correctly judge emissions system operation. Who is correct?

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

Question 48

The threshold for diesel engine misfire detection is ____ per 1,000 crankshaft revolutions.

A)4%"
B)6%"
C)8%
D)10%"

Question 49

Which of the following is NOT used by the OBDII (On Board Diagnostics Generation II) system to prevent emission systems from fraudulent testing and tampering?

A)Vehicle identification numbers (VIN)"
B)Calibration identification numbers (CAL ID)"
C)Calibration verification numbers (CVN)
D)Diagnostic trouble codes (DTC)"

Question 50

The misfire detection monitor was noncontinuous until:

A)2013"
B)2014"
C)2015
D)2016"

Question 51

Two technicians are describing exhaust gas recirculation monitor operation. Technician A says that the efficiency of the cooler is monitored by comparing exhaust gas temperature entering and leaving the cooler. Technician B says that the components of the EGR system and associated circuits are evaluated by the monitor after EGR flow is evaluated. Who is right?

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

Question 52

Which OBD input sensor will detect less fresh airflow into the engine when the EGR valve opens because EGR gas replaces fresh intake air?

A)MAP (manifold absolute pressure)"
B)EGR flow"
C)MAF (mass air flow)
D)EGR valve position sensor"

Question 53

Which of the following allowed anyone with an Android phone to read and clear fault codes, as well as access a tremendous volume of other OBD (on-board diagnostics) data?

A)Arduino chip EL327"
B)Scan tool adapter"
C)PDA (personal data assistant)
D)Apple iPhone"

Question 54

OBD (on-board diagnostics) use how many different diagnostic services, more commonly known as OBD modes?

A)4"
B)6"
C)8
D)10"

Question 55

Which of the 10 OBD (on-board diagnostics) modes enables the scan tool or software to perform onboard activation tests?

A)Display DTCs"
B)Clear DTCs"
C)Request vehicle information
D)Control operation of onboard component/system"

Question 56

Since 2004, what SAE standard has enabled a unique network interface communication device to upload new software?

A)J2534"
B)J1930"
C)J1922
D)J2535"

Question 57

Two technicians are explaining (MPC) model predictive control and fault accommodation. Technician A says that MPC uses advanced algorithms that generate virtual lookup tables for control loops while the vehicle is in operation. Technician B says that MPC control can be observed by watching videos of engine simulators in which a 3D representation of an engine rotates and responds to inputs. Who is right?

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

Question 58

MPC (model predictive control) can compensate for component wear and deterioration by generating a new set of:

A)DTCs (diagnostic trouble codes)"
B)Case-based reasoning facts"
C)Engine parameters
D)Lookup tables"

Question 59

Technician A says that it's important to study engine data during a road test to diagnose MPC (model predictive control) corrections, which diminish power output and increase fuel consumption. Technician B says that you compare data values with other vehicles in known good condition to identify the discrepancy and diagnose which component or system may be changing the MPC of virtual lookup tables. Who is right?

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

Question 60

Technician A says that MPC (model predictive control) of engines and powertrains can change the algorithm that generates a virtual lookup table to accommodate faults. Technician B says that MPC (model predictive control) can compensate for component wear and deterioration by generating a new set of lookup tables. Who is right?

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