Deck 33: Vehicle Computer Systems

Question 1

Which of the following is NOT one of the three stages of a vehicle computer, processing cycle?

A) data input
B) data processing
C) outputs
D) multiplexing

Answer 1

multiplexing

Question 2

Which of the following fits the description of multiplexing?

A) multiple vehicle computers networked by a data bus
B) GPS communications
C) vehicle ECM to PC communications
D) laptop to vehicle data bus handshake networking

Answer 2

multiple vehicle computers networked by a data bus

Question 3

Which type of memory is retained electronically in a vehicle ECM?

A) ROM
B) PROM
C) RAM
D) EEPROM

Answer 3

RAM

Question 4

When memory in a vehicle ECM is described as being volatile, what happens to it when the ignition is turned off?

A) it is written to EEPROM
B) it is retained magnetically
C) it is activated until the next start cycle
D) it is lost

Question 5

Which of the following acronyms is another way of saying main memory?

A) ROM
B) CPU
C) RAM
D) ECU

Question 6

Which of the following is commonly used to convert the results of ECM processing into action?

A) sensors
B) actuators
C) potentiometers
D) thermistors

Question 7

When two chassis electronic systems are required to exchange information and their operating protocols do not match, what is required to make communication possible?

A) transducers
B) translator box
C) interface or gateway module
D) power supply module

Question 8

Which acronym is used to describe the type of memory that would be retained when the ignition is key-off, but lost if the battery were disconnected?

A) RAM
B) NV-RAM
C) ROM
D) EEPROM

Question 9

Which of the following memory categories is designed to be the most permanent?

A) RAM
B) ROM
C) PROM
D) EEPROM

Question 10

Which of the following would accurately describe engine fuel map programming in a typical truck engine ECM?

A) fully hard-valued: can never be altered
B) soft valued: constantly altered by processing cycle
C) can be altered only by customer data programming
D) can be altered only by proprietary data programming

Question 11

Which of the following categories of devices is used to signal input data to an ECM during engine operation?

A) sensors
B) actuators
C) drivers
D) scan tools

Question 12

When files are transferred from a mainframe computer to a PC, they are:

A) recorded
B) downloaded
C) uploaded
D) burned

Question 13

What type of device is used as a coolant temperature sensor on a typical truck engine management system?

A) NTC thermistor
B) PTC thermistor
C) pyrometer
D) infrared thermometer

Question 14

What happens to resistance in an NTC thermistor when temperature increases?

A) nothing
B) decreases
C) increases
D) reverse biases

Question 15

When an NTC thermistor is used as an oil temperature sensor, what happens to the signal voltage when oil temperature increases?

A) nothing
B) decreases
C) increases
D) reverse biases

Question 16

What is the usual V-Ref value in diesel engine management systems?

A) less than 1 V-DC
B) 5 V-DC
C) 8 V-DC
D) 12.6 V-DC

Question 17

Which of the following devices does NOT require a V-Ref input?

A) thermistor
B) variable capacitance type sensor
C) potentiometer
D) induction pulse generator

Question 18

What type of output does an induction pulse generator (used to read shaft or rotor speed) produce?

A) AC
B) DC
C) PWM
D) constant frequency

Question 19

Which of the following inputs to an engine management ECM would be most likely categorized as foreground processing?

A) coolant temperature
B) oil temperature
C) rail fuel pressure
D) throttle position sensor

Question 20

When an engine turns at 2000 rpm, how long does it take to complete one full revolution?

A) 0.003 seconds
B) 0.030 seconds
C) 0.300 seconds
D) 30 nano seconds

Question 21

Which of the following customer data programming options could be described as toggle options?

A) road speed governing
B) maximum engine speed
C) LS or VS governing
D) hard cruise limits

Question 22

Technician A says that before performing proprietary reprogramming of an engine ECM, any fault codes should be cleared. Technician B says that in some cases following a proprietary data reprogramming procedure, a verification file has to be uploaded to the OEM data huB. ho is right?

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

Question 23

An engine management system that has adapted existing hydromechanical fueling devices for control by computer is known as:

A) hybrid
B) semi-cybernetic
C) partial authority
D) retrofitted

Question 24

The non-volatile, read/write/erase memory component in a truck ECM is known as:

A) ROM
B) PROM
C) EEPROM
D) DVD

Question 25

Technician A says that some OEMs used the term flash memory to describe any type of programmable onboard memory. Technician B says that true flash memory transfers more quickly than EEPROM because it batched in blocks of bytes. Who is correct?

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

Question 26

What type of mass airflow (MAF) sensor measures pressure differential at two points either side of a venturi?

A) hot wire
B) critical flow venturi
C) vortex airflow
D) eddy current

Question 27

What is a stepper motor used for?

A) precision positioning of a shaft
B) precisely controlling rpm
C) linear proportioning of an actuator
D) climate control fan speed

Question 28

Which of the following is a disadvantage of a solenoid actuator when compared with a piezo actuator?

A) mechanical movement is severely limited
B) are more bulky in size
C) slow response
D) high cost

Question 29

In which of the following output devices would you be more likely to find a piezo actuator?

A) linear proportioning solenoid
B) electrohydraulic injector (EHI)
C) non-contact TPS
D) stepper motor

Question 30

Technician A says that flash memory stores data in blocks of bytes rather than byte by byte. Technician B says that flash memory is slower to log data than EEPROM. Who is correct?

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

Question 31

Technician A says that the term flashing has come to mean any kind of programming to ECMs in the commercial vehicle industry. Technician B says that when new files are flashed to ECM memory, a verification file usually has to be uploaded to the OEM data hub to confirm the new programming. 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 Hall-effect throttle position sensors (TPS) are configurable to either digital or analog input circuits as required by the application. Technician B says that a disadvantage of Hall-effect TPS is that the contact wiper wears at an accelerated rate. Who is correct?

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

Question 33

When processing the signal from an inductive pulse generator used to measure shaft rotational speed, which of the following is used to process the signal to an rpm value?

A) DC voltage
B) AC voltage
C) Amperage
D) Frequency

Question 34

Which of the following best describes the operating principal of a critical flow venturi (CFV) used as a MAF sensor?

A) piezo pressure sensor
B) venturi and pressure differential flow
C) thermistor
D) galvanic transducer

Question 35

Where would a platinum resistance thermometer (PRT) most likely be found on a current truck?

A) within the cylinder exhaust tract
B) charge air cooler (CAC)
C) turbine housing
D) diesel particulate filter (DPF

Question 36

When a stepper motor is driven by an 8 bit controller, how many 'steps' in the rotation can its rotor be positioned in?

A) 8
B) 64
C) 128
D) 256

Question 37

When the piezo stack in a piezo-actuator is hit with an electrical trigger, which of the following best describes the time required for a mechanical response?

A) almost instantly
B) lagged by time required to build field
C) lagged by time required to overcome counter electro-motive force (CEMF)
D) slower than an equivalent solenoid actuator

Question 38

Technician A says that some types of NOx sensor use a galvanic operating principle. Technician B says that galvanic type NOx sensors must be powered up using V-Ref. Who is correct?

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

Question 39

Technician A says that a WIF sensor uses a couple of probes that measure the dielectric properties of water versus that of fuel. Technician B says that dielectric properties refers to electrical resistivity. Who is correct?

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

Question 40

?What is a polyswitch?

A) ?A new kind of stalk switch
B) ?A PTC circuit protection device
C) ?A multi-position toggle switch
D) ?A programmable function, generic smart switch

Question 41

If you had to classify a Freightliner SAM into one of the following categories, which would you select? ?

A) ?MCM
B) ?CPC
C) ?PLD
D) ?ECU

Question 42

?Which of the following best describes the function of a Freightliner central gateway?

A) ?Enables communications between J1939 and other chassis data buses
B) ?Required to permit geofence V2V communications
C) ?Termination block to damp electronic noise
D) ?Any DDL access socket

Question 43

Which of the following best describes the function of a Freightliner central gateway??

A) ?Enables communications between J1939 and other chassis data buses
B) ?Required to permit geofence V2V communications
C) ?Termination block to damp electronic noise
D) ?Any DDL access socket

Question 44

Technician A says that multiple sensors such as those for temperature and pressures may be incorporated into what appears to be a single device. Technician B says that chassis body controllers such as SAMs must be capable of communicating with the powertrain bus in current truck chassis. Who is correct??

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