Deck 8: Automotive Multiplexing and Networking of Computers

Question 1

How do manufacturers reduce the effects of an induced voltage in a single-wire (SW) multiplexed circuit?

A) A relay is designed to open the data bus circuit if it senses an induced voltage.
B) A spike diode is placed in each of the data bus wires.
C) The modules communicate with digital on/off signals that have a slight angle at the edges (are trapezoidal in shape).
D) The data bus wire is twisted with a ground wire.

Answer 1

C

Question 2

Which acronym applies to the portion of the binary message that allows the receiving module to detect message errors through a mathematical calculation?

A) IFR
B) CRC
C) VPW
D) PWM

Answer 2

B

Question 3

Which quality is attributed to multiple body computers?

A) They save money.
B) They eliminate data transmission.
C) They reduce hard wiring.
D) They reduce complexity.

Answer 3

C

Question 4

J1850 messaging is being discussed. Which portion of the message immediately follows the start-of-frame signal?

A) The data field
B) The cyclical redundancy check
C) The in-frame response
D) The header

Question 5

In a J1850 protocol, the process of determining which node can continue to transmit data on the bus when two or more nodes begin transmitting at the same time is known as:

A) Messaging
B) Arbitration
C) Decision making
D) Dominant bias

Question 6

It has been shown that emergency response vehicles can be disabled through the installation of a computer virus through with method?

A) Plugging in a scan tool
B) Scanning the vehicle with a QR code reader
C) Magnetically applying a device to the body of the vehicle
D) Broadcasting a signal in a public location

Question 7

Newer configurations tend to wire the nodes to the data bus in a parallel fashion, known as a _____ topology.

A) series
B) star
C) linear
D) star or linear

Question 8

Which function is likely to be controlled by a body control module (BCM)?

A) Ignition
B) Automatic transmission shifts
C) Interior lights
D) Battery charging

Question 9

Technician A says on  pulse width modulated (PWM) busses, all bits are the same length. Technician B says on variable pulse width (VPW) designs,  one pulse may be long and the next pulse may be short. Who is correct?

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

Question 10

Why are the two wires of a twisted-pair multiplex system twisted?

A) To reduce the effects of induced voltage
B) To reduce the chance of wires shorting out
C) To make the circuit more complex
D) To maximize communication speed

Question 11

A standardized binary code (or computer language) is known as a:

A) Node
B) Protocol
C) Passive communication
D) Active communication

Question 12

Fiber optic protocols are being discussed. Technician A says BMW uses five data buses on the E65 model. Technician B says one of the fiber optic data buses used by BMW is known as MOST. Who is correct?

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

Question 13

During vehicle diagnosis, you discover that the scan tool will not communicate with the network. All of these checks should be made EXCEPT :

A) Make sure the VIN entry in the scan tool is correct
B) Determine that battery voltage is available at pin 16 of the DLC
C) Use a lab scope to determine whether data is present on the bus
D) Use a lab scope to interpret the data on the bus

Question 14

Which protocol was first used on the 1991 Mercedes S-Class to provide an intra-vehicle communication network between the nodes on a bus?

A) UART
B) SAE-J1850
C) CAN
D) ISO-9141-2

Question 15

Which characteristic(s) describe advantages of multiplexed circuits over hard-wired circuits?

A) Elimination of wiring and wiring connectors, thus reducing vehicle weight while adding reliability
B) Lower cost to manufacture
C) Increased computer diagnostic abilities
D) All of the above

Question 16

What does the term baud rate mean?

A) The number of modules that can communicate at the same time
B) The speed of communication
C) The length of the communication
D) The language that the computer uses

Question 17

Why should a DSO be used in diagnosing a vehicle's multiplexing bus?

A) To pull diagnostic trouble codes (DTCs) from the computers on the bus
B) To look at fuel trim information
C) To check monitor readiness status
D) To check for the presence of serial data (binary code) when a scan tool fails to communicate

Question 18

The computer that is the dominant node on the bus and controls the data bus is known as the _____.

A) dominated module
B) master node
C) slave node
D) secondary node

Question 19

The bus-H and bus-L circuits of a dual wire (DW) bus used on a Ford are being viewed on a dual-channel oscilloscope. Technician A says the waveforms should be identical. Technician B says the waveforms should mirror each other. Who is correct?

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

Question 20

Which acronym applies to serial data in which the "ones" and "zeros" are defined not only by the voltage value but also by the bit length (a "one" can be a short high-voltage pulse or a long low-voltage pulse and a "zero" can be a short low-voltage pulse or a long high-voltage pulse)?

A) IFR
B) CRC
C) VPW
D) PWM