Deck 12: Multiplexing

Question 1

What field in a data packet is used to define the urgency of a broadcast over the data bus?

A) ack
B) control
C) start of frame
D) arbitration

Answer 1

D

Question 2

What color is assigned to the physical power line carrier (PLC)communication between a tractor and trailer?

A) white
B) blue
C) black
D) brown

Answer 2

B

Question 3

What universal standards are used to ensure that control module interconnectivity on J1939 adheres to both national and international standards?

A) FMVSS 121 and FMVSS 108
B) ISO 9141 and ISO 11898
C) RP 649 and RP 651
D) ISO 9000 and ISO 9001

Answer 3

B

Question 4

Which of the following methods are used to access diagnostic codes from a controller with an address on a truck data bus?

A) flash codes
B) PC-based EST
C) generic HH-EST
D) All of the above

Question 5

Technician A says that if one module networked to a J1939 data bus fails,it should not affect the operation of other modules on the bus.Technician B says that an advantage of using a data bus,is that controllers on the bus can share input signals from key components such as a TPS.Who is correct?

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

Question 6

Technician A says that a black J1939 9-pin DLC can be connected to a green J1939 9-pin receptacle.Technician B says that a green J1939 9-pin DLC can be connected to a black J1939 9-pin receptacle.Who is correct?

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

Question 7

On a truck data bus,how many wires are used to broadcast J1939 message packets?

A) one
B) two
C) nine
D) seventy two

Question 8

What is another way of saying algorithm in a vehicle computer processing cycle?

A) mapping
B) computing
C) driving
D) switching

Question 9

How does power line carrier (PLC)trailer-to-tractor multiplexing transmit messages?

A) radio frequency signals superimposed over 12-volt auxiliary wire
B) wirelessly
C) optically using auxiliary fiber optics
D) twisted wire pair

Question 10

Which source address (SA/MID)code identifies the address of the transmission electronics on a truck data bus?

A) SA01/ MID128
B) SA03/ MID130
C) SA11/ MID136
D) SA23/ MID140

Question 11

Three of the following mean the same thing.Which is the odd one out?

A) Internet
B) data bus
C) neural network
D) multiplex backbone

Question 12

Technician A says that most trucks that use a J1939 data bus have provision for the older J1587/1708 data bus.Technician B says that the current J1939 data bus is based on CAN 2.0 communications protocols.Who is correct?

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

Question 13

Which of the controllers is 'in charge' of managing data on a truck J1939 data bus?

A) bus topology ensures that no individual controller has this role
B) engine management ECM
C) chassis management ECU
D) instrument cluster module (ICU)

Question 14

What is the current automotive/ light-duty truck equivalent of the J1939 data bus used on medium/heavy trucks on passenger cars and light duty trucks?

A) J-1587
B) J-1708
C) CAN-A
D) CAN-C

Question 15

What type of data connector is required to access a SAE J1939 data bus?

A) 9-pin black Deutsch
B) 9-pin green Deutsch
C) J1962
D) All of the above

Question 16

Which of the following are advantages of a multiplexed truck chassis?

A) reduction in the hard wire circuit
B) reduction of input hardware
C) information sharing between controllers
D) all of the above

Question 17

What is the advantage of using serial data transmission on a current truck data bus as compared with a multiple track (parallel)model?

A) lower failure rates
B) lower overall costs
C) higher speeds
D) higher data volumes

Question 18

Which of the following is another way of saying data bus communications?

A) computer processing
B) multiplexing
C) flash programming
D) downloading

Question 19

What type of data connector is associated with the SAE J1587/1708 data bus?

A) Weatherproof
B) Weatherpac
C) 6-pin Deutsch
D) 9-pin Deutsch

Question 20

When power line carrier (PLC)multiplexing is used,what vehicle system is it associated with?

A) transmission electronics
B) trailer ABS
C) proprietary buses
D) instrument cluster unit (ICU)

Question 21

What is each data 'message' known as in a multiplexed truck system?

A) server
B) client
C) signal
D) packet

Question 22

How many terminating resistors are required on a J1939 data backbone?

A) one
B) two
C) three
D) four

Question 23

Technician A says that the physical distance between the two wires on a twisted wire pair determines their capacitance,with capacitance decreasing as the wires become further apart,accounting for the fact that replacement is usually preferred over repair.Technician B says that the insulation wrap over a twisted wire pair also defines the capacitance which explains why it should never be replaced with ordinary wire.Who is correct?

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

Question 24

What is the maximum permissible,physical length of a J1939 data bus?

A) 12 feet (3.5 meters)
B) 40 feet (12 meters)
C) 130 feet (40 meters)
D) 180 feet (55 meters)

Question 25

Technician A says that CAN L (-)and (chassis)ground are of equal voltage potential.Technician B says that modules networked to a J1939 bus are designed to identify the difference between CAN H (+)and CAN L (-)in message packet without reference to chassis ground.Who is correct?

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

Question 26

Technician A says that a high bus backbone consists of a twisted wire pair wound with bare copper wire and wrapped with a foil shield.Technician B says that the bare copper wire used in a high bus backbone is known as the drain.Who is correct?

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

Question 27

What is the maximum permitted length of an stub extending from a J1939 data bus?

A) 12 inches (0.3 meter)
B) 24 inches (0.6 meter)
C) 30 inches (0.75 meter)
D) 40 inches (1 meter)

Question 28

What term is used to describe the volume of data that can be handled on a data bus?

A) current
B) bandwidth
C) frequency
D) clock pulses

Question 29

What is the usual voltage differential used on the J1939 data backbones to transmit message packets?

A) 12-volts
B) 8-volts
C) 5-volts
D) 2-volts

Question 30

What is used to rate the transaction speed of a multiplexed data backbone?

A) K-baud
B) processor clock speed
C) speed of light
D) hertz

Question 31

Technician A says that some OEMs permit physical repairs on high bus wiring providing guidelines in their service literature are observed.Technician B says that low bus wiring can never be repaired once damaged.Who is correct?

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

Question 32

Technician A says that processors networked to J1939 data bus must have clock speeds of at least 16 MHz.Technician B says that a frequency of 16 MHz translates into a capability of making 16,000 binary decisions per second.Who is correct?

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

Question 33

A twisted wire pair requires a full cycle twist of the wires for every ____ distance of travel.

A) one centimeter
B) one inch
C) two and one half inches
D) six centimeters

Question 34

Which companies were responsible for developing the CAN data bus standards that are now used in both automotive and truck multiplex systems?

A) Motorola and Delco
B) Delphi and Lucas
C) Bosch and Intel
D) IBM and HP

Question 35

When several SAs/MIDs attempt to broadcast messages over a truck data bus simultaneously,what process ensures that the message with the highest priority gets broadcast first?

A) ack field
B) bus arbitration
C) message tag
D) start of frame

Question 36

Technician A says that there can be up to 2 open Tees on a J1939 data backbone.Technician B says that most truck data backbones use electrical pressures of around 5 volts.Who is correct?

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

Question 37

What is the resistance of a terminating resistor used on a J1939 data backbone?

A) 8 ohms
B) 56 ohms
C) 120 ohms
D) 256 ohms

Question 38

What is the reason for using a twisted wire pair for the data backbone on J1939 buses?

A) reduces surface area on which electromagnetic interference can act
B) increases the surface area available for electromagnetic transmission
C) increases the overall toughness of the wire
D) reduces the transmissions speeds of data packets to an acceptable level

Question 39

Technician A says that a disadvantage of multiplexing is that it increases the amount of wiring on a vehicle chassis.Technician B says that a Navistar Diamond Plus multiplex dash has just 7 wires as opposed to over 60 wires on earlier Navistar dash.Who is correct?

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

Question 40

Which of the following messages broadcast to a truck data bus would probably be assigned the highest priority?

A) change in oil temperature status
B) drop in ambient pressure
C) change in throttle position
D) panic brake application

Question 41

What is used on a green 9-pin J1939 bus DLC receptacle to block access by a black DLC?

A) smaller CAN-H cavity in receptacle
B) smaller F-pin cavity in receptacle
C) larger F-pin cavity in receptacle
D) larger CAN-L cavity in receptacle

Question 42

Technician A says that low bus connectors within a J1939 data bus use a 6-pin connector.Technician B says that high bus connectors within a J1939 data bus use a 3-pin connector.Who is correct?

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

Question 43

If a communications adapter (CA)is RP 1210 compliant,what should it be capable of doing?

A) acting as a serial link between a the data bus and a PC
B) deciphering hexadecimal code
C) diagnosing non-communicating nodes on the bus
D) replacing the requirement for OEM EST-software

Question 44

If the J1939 connection was lost,how would the driver of the vehicle know this had occured?

A) rig would shutdown immediately
B) engine would shutdown
C) check engine light would illuminate
D) dash display alert

Question 45

What is the source address (SA)on the J1939 bus of the transmission controller?

A) SA 00
B) SA 03
C) SA 12
D) SA 25

Question 46

Which of the following DLCs would be required to access the J1939 data bus of most MY 2014 and later trucks?

A) black J1708
B) black J1939
C) green J1939
D) 16-pin J1962

Question 47

When the LED on a smart switch first flashes,then stays illuminated,what does that tell the operator?

A) switch command is in the process of being effected
B) switch command cannot be effected
C) switch command has been completed
D) switch is defective

Question 48

What is another way of saying smart switch?

A) bridge switch
B) ladder switch
C) toggle switch
D) binary switch

Question 49

What is used to circuit protect FET switched headlamp and electric wipers in a typical multiplex chassis?

A) virtual logic type 1 cycling
B) virtual logic type 2 non-cycling
C) SAE #1 cycling circuit breaker
D) SAE #2 non-cycling circuit breaker

Question 50

How many terminating resistors are there in a typical smart switch ladder bridge?

A) one for each switch status
B) two
C) three
D) five

Question 51

When a global parameter group number (PGN)message is broadcast on J1939,what does it target?

A) exclusively to a reader EST
B) a discreet controller on the bus
C) a specific SA on the bus
D) any SA on the bus

Question 52

Technician A says that Navistar Diamond Plus multiplexing uses virtual fusing logic to protect FET switched circuits.Technician B says that there are two types of virtual fusing logic used,type 1 cycling and type 2 non-cycling.Who is correct?

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

Question 53

What is the characteristic impedance of a J1939 data bus?

A) 25 ohms
B) 75 ohms
C) 120 ohms
D) 180 ohms

Question 54

Technician A says that field effect transistor (FET)is commonly used in multiplexed circuits to act like an electronic relay switch.Technician B says that an advantage of FETs is that gate channel resistance is so high there is almost no current flow in the gate.Who is correct?

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

Question 55

Technician A says that a scopemeter can help technicians interpret hexadecimal code for troubleshooting purposes.Technician B says that a labscope may help to identify a non-communicating node (controller)on the buse.Who is correct?

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

Question 56

Technician A says that if one terminating resistor was missing from a J1939 data bus,it would likely function without problems.Technician B says that if both terminating resistors were missing from a chassis data bus,no data transactions would be possible.Who is correct?

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

Question 57

Technician A says that HH-ESTs,OEM software,and a DLC can be used to access a J1939 data bus.Technician B says that a generic HH-EST loaded with a general heavy duty reader software can be used to program customer data to controller modules on the data bus.Who is correct?

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

Question 58

When the LED on a smart switch flashes,what does that tell the operator?

A) switch command is the process of being effected
B) switch command cannot be effected
C) switch command has been completed
D) switch is not functioning

Question 59

Technician A says that diagnostic trouble codes (DLCs)are tagged with an FMI.Technician B says that every DLC is tagged with an OC.Who is correct?

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

Question 60

Which of the following DLCs is required to access J1939 on a Volvo-Mack chassis MY 2014 or later?

A) black J1708
B) black J1939
C) green J1939
D) 16-pin J1962