Computerized Engine Controls 10th

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Computerized Engine Controls 10th Edition Hatch Test Bank

Name: Class: Date:

Chapter 2
Computers in Cars

1. What decimal (base 10) value is represented by the binary code “10110011”?
a. 14 b. 115
c. 179 d. 243
ANSWER: c
POINTS: 1

2. What does a “baud rate” of 41,600 mean?

a. 41,600 bits are communicated per second b. 41,600 bits are communicated per minute
c. 41,600 bytes are communicated per second d. 41,600 bytes are communicated per minute
ANSWER: a
POINTS: 1

3. A scan tool is displaying the hexadecimal value for the binary code “1010000100111110”. Which hex value
is displayed on the scan tool?
a. $A13E b. $1010
c. $B2CF d. $A690
ANSWER: a
POINTS: 1

4. Which component is a memory type that allows the microprocessor to change the information that is stored in it?
a. ROM b. PROM
c. RAM d. CPU
ANSWER: b
POINTS: 1

5. Which component in an engine computer is a volatile memory and stores sensor input values until updated,
strategy results, fuel trim data, and memory type fault codes?
a. ROM b. PROM
c. RAM d. CPU
ANSWER: c
POINTS: 1

6. Which of the following defines a computer input?

a. Voltage & ground supplied to power up the computer b. A signal from a sensor that measures
various conditions
c. Stored information in memory that the computer uses d. A command signal to a relay, a motor, or
in making decisions a solenoid
ANSWER: b
POINTS: 1

7. Technician A says that a PCM uses an output actuator to keep itself informed of engine operating
conditions. Technician B says that a PCM uses an output actuator to cause a change in the performance of a
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Name: Class: Date:

Chapter 2
Computers in Cars

circuit or system. Who is correct?

a. Technician A only b. Technician B only
c. Both A and B d. Neither A nor B
ANSWER: b
POINTS: 1

8.

Concerning the logic gate pictured in Figure 3 above, which condition would produce binary "one" for “C” (the
output)?
a. “A” is a “zero” and “B” is a “one” b. “A” is a “one” and “B” is a “zero”
c. “A” and “B” are both “ones” d. All of the above
ANSWER: c
POINTS: 1

9. A vehicle’s engine computer does not operate properly. The vehicle’s battery is checked with a DVOM and
has an open circuit voltage of 8.3 volts.
Technician A says that the PCM is probably defective and should be replaced. Technician B says that, before
condemning the PCM, the battery should be charged and retested. Then the appropriate voltage drop tests of
the PCM’s power and ground circuits should be performed. Who is correct?
a. Technician A only b. Technician B only
c. Both technicians d. Neither technician
ANSWER: b
POINTS: 1

10. Which of the following is NOT required in order for an engine computer to enter closed loop operation?
a. The oxygen sensor must be up to operating b. The engine’s coolant temperature must be
temperature. at or above a specified temperature.
c. The vehicle must be at or above a designated d. A specified time period must have passed
speed as measured by the vehicle speed sensor. since the engine was started.
ANSWER: c
POINTS: 1

11. In addition to providing voltage to the computer’s internal circuits, what is the purpose of the reference
voltage regulator within a modern PCM?
a. To provide 5 volts to the sensors on the input b. To provide 5 volts to the actuators on the output
side of the PCM side of the PCM
c. To provide 12 volts to the sensors on the input d. To provide 12 volts to the actuators on the
side of the PCM output side of the PCM
ANSWER: a
POINTS: 1
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Chapter 2
Computers in Cars

12. “Closed loop” is defined as a system operating mode:

a. in which the computer becomes part of a b. in which the computer ignores the input
communications loop with other computers from the oxygen sensor
c. in which the computer monitors the results of its own d. that the computer enters only when the
control throttle is closed
ANSWER: c
POINTS: 1

13. Which gas is naturally produced within the engine’s cylinders through combining the hydrogen atom of the
HC molecule with atmospheric oxygen?
a. CO b. CO2
c. NOX d. H2O
ANSWER: d
POINTS: 1

14. Technician A says that closed loop is the most efficient operating mode and allows the engine computer to
control the air-fuel ratio with the most precision. Technician B says that open loop operation is used to improve
performance during cold engine warm-up and is also used under heavy load or during wide open throttle
operation. Who is correct?
a. Technician A only b. Technician B only
c. Both technicians d. Neither technician
ANSWER: c
POINTS: 1

15. What is indicated if the oxygen sensor voltage is cycling back and forth across the stoichiometric value
several times per second?
a. The air-fuel ratio is too lean and the voltage b. The air-fuel ratio is too rich and the voltage
cannot stabilize cannot stabilize
c. The computer is properly controlling the air- d. The computer is malfunctioning
fuel ratio
ANSWER: c
POINTS: 1

16. Which operating condition(s) has/have the programmed goal of _____ maintaining a stoichiometric air-fuel ratio?
a. open loop operation only b. closed loop operation only
c. both closed loop and open loop operation d. limp-in mode only
ANSWER: b
POINTS: 1

17. What is the advantage of controlling the air-fuel ratio to a stoichiometric ratio?
a. A stoichiometric ratio reduces the production of b. A stoichiometric ratio helps the three-way

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Computerized Engine Controls 10th Edition Hatch Test Bank

Name: Class: Date:

Chapter 2
Computers in Cars

toxic emissions within the engine’s cylinders catalytic converter perform at its peak
efficiency
c. A stoichiometric ratio increases the potential for d. Both A and B
performance when the engine is under heavy
load
ANSWER: d
POINTS: 1

18. Which air-fuel ratio would provide the most power?

a. 14.4:1 b. 12.5:1
c. 14.7:1 d. 16:1
ANSWER: b
POINTS: 1

19. Which designation is NOT one of the three basic logic gates from which all of the more complex gates are built?
a. AND gate b. OR gate
c. NOR gate d. NOT gate
ANSWER: c
POINTS: 1

20. Exhaust gasses are being discussed. Technician A says nitrogen (N) is considered a harmful gas. Technician B says
carbon monoxide (CO) is considered a harmful gas. Who is correct?
a. Technician A only b. Technician B only
c. Both A and B d. Neither A nor B
ANSWER: b
POINTS: 1

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