Chapter 24 Sensor, Actuator, Computer Service 481
3. While discussing computer system problems,
Technician A says poor electrical connections are the
most common causes of electrical-related problems.
Technician B says that vacuum leaks can upset
computer system operation. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.
4. A variable resistance type sensor must be tested.
Technician A disconnects the reference voltage wire
and measures the sensor’s resistance. Technician B
measures the voltage drop across the sensor without
disconnecting the reference voltage wire. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.
5. An engine’s oxygen sensor is believed to be
malfunctioning. Technician A checks the
sensor’s output voltage with an analog voltmeter.
Technician B checks the sensor’s output voltage with
a high-impedance digital VOM. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.
6. An automobile computer system triggers a trouble
code indicating a MAP sensor circuit problem. After
performing a preliminary inspection, Technician A
checks sensor circuit voltage while applying vacuum
to the sensor. Technician B checks sensor resistance
while applying vacuum to the unit. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.
7. Which of the following is least likely to cause a
severe engine performance problem?
(A) Faulty manifold absolute pressure sensor.
(B) Defective throttle position sensor.
(C) Bad intake air temperature sensor.
(D) Faulty coolant temperature sensor.
8. Technician A says a defective knock sensor can
affect ignition timing. Technician B says a defective
knock sensor can affect turbocharger boost pressure.
Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.
9. A vehicle’s idle air control valve is believed to be
faulty. Technician A applies battery voltage to the
valve’s windings and watches for changes in engine
speed. Technician B checks the output voltage to the
idle air control valve. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.
10. An automobile computer’s output signals must
be checked. Technician A says a voltmeter can
be used to check the computer’s output signals.
Technician B says an oscilloscope can be used to
check the computer’s output signals. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.