Deck 11: Vehicle Communication Networks Vehicle Multiplexing Diagnostics

Question 1

To isolate a class A bus circuit that is shorted to battery voltage, all of the following methods can be used EXCEPT:

A) Use a jumper wire and connect the faulty circuit to ground.
B)Turn the ignition switch off to see if it is switched voltage.
C) Pull fuses one at a time to determine the shorted circuit.
D)Pull relays one at a time to determine shorted circuits or components.

Answer 1

A

Question 2

The lab scope trace of an ISO-K bus system shows the voltage going to −0.5 volts. This would indicate:

A) The scan tool bias voltage.
B) The module attempting to transmit data to the scan tool.
C) The scan tool attempting to request data from the module.
D) Excessive electrical noise on the circuit.

Answer 2

C

Question 3

On a LIN bus, zero volts are indicated on the bus circuit with the slave module disconnected. What is the LEAST likely cause?

A) An open circuit between the master module and the slave module connector.
B)A shorted circuit between the master module and the slave module connector.
C) Faulty master module.
D)Faulty slave module.

Answer 3

D

Question 4

In the CAN bus system:

A)CAN B is high speed and not fault tolerant.
B)CAN C is fault tolerant.
C)Can C is low speed and used for many body control functions.
D)None of these choices.

Question 5

In the local interconnect network (LIN) bus:

A)The master controller is connected to the CAN bus and controls the data transfer speed.
B)The master controller translates data between the slave modules and the CAN bus.
C)Supporting up to 15 slave modules is possible.
D)All of these choices.

Question 6

If one of the CAN C bus circuits were shorted to ground, all of the following could occur EXCEPT:

A) No-start.
B) No communication between scan tool and any CAN C modules.
C) Central Gateway Module logs a loss of communication fault code against CAN C modules.
D) The bus will operate in single-wire mode.

Question 7

All of the following statements concerning multiplexing are true EXCEPT:

A)Hard wiring and vehicle weight are reduced.
B)A single computer controls all of the vehicle functions.
C)Enhanced diagnostics are possible.
D)Reduces driver requirements in the computer.

Question 8

All of the following can cause total bus failure of the J1850 VPWM bus system, EXCEPT:

A) Open bus wire to the BCM.
B) Bus wire shorted to ground.
C) Bus wire shorted to battery voltage.
D) Internal short in a module.

Question 9

In a single-wire bus network, EMI is controlled by:

A)Using a shielded wire.
B)Slowly ramping up and down the voltage levels.
C) Locating the wire outside of the normal wiring harness.
D) None of these choices.

Question 10

In a J1850 VPWM bus system, how can a short to ground be isolated?

A) Use a jumper wire to supply battery voltage to pin 2 of the DLC while observing the DMM.
B) Disconnect in-line connectors one at a time while observing the DMM.
C) Use a jumper wire to short pin 15 of the DLC to ground while observing the DMM.
D) All of these choices.

Question 11

Protocol is defined as:

A)A common communication method.
B)A method of reducing EMI.
C) Data transmission through a single circuit.
D)All of these choices.

Question 12

On a data bus that uses two wires, why are the wires twisted?

A)To increase the physical strength of the wires.
B)For identification of the circuit.
C)To reduce the effect of the high current flow through the bus wires on other circuits.
D)To minimize the effects of an induced voltage on the data bus.

Question 13

A class A bus that has zero volts on both bus circuits may indicate:

A) Both circuits are shorted to ground.
B)The master module's power feed circuit is open.
C)An open bus connector to the master module.
D)All of these choices.

Question 14

A computer that can communicate on a data bus is known as:

A) Node.
B) Byte.
C) Protocol.
D) Transceiver.