Deck 3: Common Components for Computerized Engine Control Systems

Question 1

What should you do when testing a knock sensor?

A) Tap it lightly with a nonmetallic object while measuring the output
B) Tap it lightly with a metallic object while measuring the output
C) Tap it lightly with a nonmetallic object while measuring the input
D) Tap it lightly with a metallic object while measuring the output

Answer 1

B

Question 2

A digital Hall effect sensor consists of all of the following EXCEPT :

A) a shutter wheel with vanes and windows
B) a permanent magnet
C) a Hall effect crystal
D) a light emitting diode

Answer 2

D

Question 3

What voltage will be produced by a zirconia O₂ sensor when the air-fuel ratio is on the rich side of stoichiometric?

A) 0 mV to 100 mV
B) 100 mV to 250 mV
C) 250 mV to 450 mV
D) 450 mV to 900 mV

Answer 3

D

Question 4

What does a digital Hall effect sensor do?

A) Senses engine speed and crankshaft position
B) Measures the amount of free oxygen in the exhaust
C) Detects temperature changes in engine coolant
D) Monitors barometric pressure

Question 5

What scale on a DVOM should be used to test a Hall effect sensor's signal?

A) An AC voltage scale
B) A DC voltage scale
C) A resistance scale
D) A diode test scale

Question 6

Which of the following sensors cannot produce or generate a voltage signal?

A) Zirconia dioxide oxygen sensor
B) Permanent magnet sensor
C) Piezoelectric sensor
D) Potentiometer

Question 7

In the figure above, if there was an open at terminal "C", what would the voltage signal to the PCM be?

A) 0 volts
B) About 1½ volts
C) About 3½ volts
D) 5 volts

Question 8

What type of sensor is a throttle position sensor?

A) Potentiometer
B) NTC thermistor
C) Piezoelectric diaphragm
D) Piezoresistive diaphragm

Question 9

Which of the following sensors may be used in place of the speed density formula?

A) MAP sensor
B) VAF meter
C) MAF sensor
D) DPFE sensor

Question 10

If the vacuum hose to a MAP sensor were to rupture, what would the likely result be?

A) The engine would continue to run well because the O₂ sensor is the primary sensor
B) The PCM would go into open loop and run the engine excessively lean
C) The PCM would go into open loop and run the engine excessively rich
D) The PCM would see this sensor as being out of normal operating limits

Question 11

What is the "speed density formula" used to determine?

A) How much air is entering the engine
B) How much fuel is entering the engine
C) How much exhaust back pressure is present
D) How much CO and HC is being produced during combustion

Question 12

Technician A says that a switch in a "pull-up circuit" provides voltage to the computer when it is closed. Technician B says that a switch in a "pull-down circuit" provides a ground to the computer when it is closed. Who is correct?

A) Technician A only
B) Technician B only
C) Both technicians
D) Neither technician

Question 13

Most often, how does the PCM energize an output actuator?

A) It supplies 5 volts to the actuator
B) It supplies battery voltage to the actuator
C) It supplies secondary ignition voltage to the actuator
D) It completes the actuator's ground path

Question 14

Which of the following types of sensors cannot be used as a RPM reference sensor?

A) Potentiometer
B) Permanent magnet
C) Optical
D) Hall effect

Question 15

Which of the following best describes how a permanent magnet sensor operates?

A) It modifies a reference voltage signal
B) It generates a DC analog voltage signal
C) It generates a DC digital voltage signal
D) It generates an AC voltage signal

Question 16

Technician A says that if a relay is normally open, it must be energized in order to complete the controlled circuit. Technician B says that if a solenoid-operated valve is normally closed, it must be energized in order to allow flow through it.Who is correct?

A) Technician A only
B) Technician B only
C) Both technicians
D) Neither technician

Question 17

All of the following sensors vary resistance so as to modify a voltage signal EXCEPT a(n):

A) potentiometer
B) NTC thermistor
C) zirconia oxygen sensor
D) piezoresistive diaphragm

Question 18

In the figure above, as the engine coolant temperature sensor's resistance decreases, how will the voltage signal to the computer change?

A) The voltage signal decreases
B) The voltage signal increases
C) The voltage signal is unaffected
D) The sensor begins producing a digital frequency

Question 19

How will an increase in temperature from 50^oF to 220 ^oF affect the resistance of an NTC thermistor?

A) The resistance decreases
B) The resistance increases
C) The resistance will be unaffected
D) The resistance should go to "infinity"

Question 20

Two technicians are discussing how to test a permanent magnet vehicle speed sensor. Technician A says that you should test the coil's resistance and compare it to specification. Technician B says that you should set your DVOM to the " DC volts " scale to test the sensor's ability to produce voltage. Who is correct?

A) Technician A only
B) Technician B only
C) Both technicians
D) Neither technician