Question 1

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

Accepted Answer

The green 9-pin J1939 bus DLC receptacle uses a smaller F-pin cavity to block access by a black DLC, ensuring that only compatible connectors are used.

Question 2

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

Accepted Answer

The answer of Technician A says that low bus connectors...

Question 3

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

Accepted Answer

RP 1210 compliance means the communications adapter can act as a serial link between the data bus and a PC, allowing for communication and diagnostics.

Question 4

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

Accepted Answer

The dash display alert would illuminate to indicate that the J1939 connection was lost.

Question 5

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

Accepted Answer

In the J1939 protocol, the source address (SA) for the transmission controller is typically SA 03. This is a standardized address used across different manufacturers and systems for identifying the transmission controller on the network.

Question 6

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

Accepted Answer

The correct choice is C) green J1939 because for most MY 2014 and later trucks, the green J1939 connector is the standard Data Link Connector (DLC) used to access the J1939 data bus. This change was made to differentiate from older systems and to standardize connections across heavy-duty vehicles.

Question 7

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

Accepted Answer

The LED flashing followed by staying illuminated typically indicates that the switch command has been completed. This is a common way for smart devices to signal successful operation or command execution to the user.

Question 8

What is another way of saying smart switch?
A) bridge switch
B) ladder switch
C) toggle switch
D) binary switch

Accepted Answer

The answer of What is another way of saying smart...

Question 9

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

Accepted Answer

The answer of What is used to circuit protect FET...

Question 10

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

Accepted Answer

A typical smart switch ladder bridge has two terminating resistors, one at each end of the CAN bus to prevent signal reflections that can cause errors.

Question 11

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

Accepted Answer

Global parameter group number (PGN) messages on the J1939 network are designed to be broadcast to any and all system addresses (SAs) on the bus, not targeted to specific devices or controllers.

Question 12

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

Accepted Answer

Both Technician A and Technician B are correct. Technician A is correct in stating that Navistar Diamond Plus multiplexing uses virtual fusing logic to protect FET (Field-Effect Transistor) switched circuits, which is a method to electronically control the protection of circuits without physical fuses. Technician B is correct in stating that there are two types of virtual fusing logic used: type 1 cycling and type 2 non-cycling, which refer to the methods by which the system manages overcurrent conditions.

Question 13

What is the characteristic impedance of a J1939 data bus?
A) 25 ohms
B) 75 ohms
C) 120 ohms
D) 180 ohms

Accepted Answer

The characteristic impedance of a J1939 data bus is 120 ohms.

Question 14

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

Accepted Answer

Both statements by Technician A and Technician B are correct. FETs are indeed used in multiplexed circuits to act like electronic relay switches due to their ability to control large currents with minimal input. Additionally, one of the advantages of FETs is the high gate channel resistance, which results in almost no current flow in the gate, making them efficient for various applications.

Question 15

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

Accepted Answer

A scopemeter or oscilloscope is not used for interpreting hexadecimal code; it is used for observing the detailed shape of electrical signals, whereas identifying a non-communicating node on a vehicle's bus system is indeed a practical application of a labscope, making Technician B correct.

Question 16

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

Accepted Answer

Technician A is correct because a J1939 data bus can still function with one missing terminating resistor, although it may not perform optimally. Technician B is also correct because if both terminating resistors are missing, the bus would likely fail to operate properly, preventing data transactions.

Question 17

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

Accepted Answer

Technician A is correct because HH-ESTs (Hand-Held Electronic Service Tools), OEM (Original Equipment Manufacturer) software, and a DLC (Data Link Connector) are indeed tools and interfaces used to access a J1939 data bus, which is a standard in the heavy-duty truck industry for communication between the various components of the vehicle. Technician B is incorrect because a generic HH-EST with general heavy-duty reader software typically cannot be used to program customer data to controller modules on the data bus; this usually requires specific OEM software or tools with the appropriate permissions and capabilities.

Question 18

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

Accepted Answer

A flashing LED on a smart switch typically indicates that the switch command is in the process of being effected.

Question 19

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

Accepted Answer

The answer of Technician A says that diagnostic trouble codes...

Question 20

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

Accepted Answer

The answer of Which of the following DLCs is required...

Quiz 12: Multiplexing

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

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?

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

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

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

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

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

What is another way of saying smart switch?

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

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

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

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?

What is the characteristic impedance of a J1939 data bus?

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?

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?

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?

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?

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

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?

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