Deck 15: Temperature Sensors

Question 1

Why does the PCM monitor engine oil temperature on some vehicles?

A) It is an OBD-II requirement
B) Used to calculate engine oil life
C) To limit RPM in case of hot oil
D) All of the above

Answer 1

B

Question 2

An exhaust gas recirculation (EGR) temperature sensor is used on ________.

A) some gasoline engines
B) most diesel engines
C) all V-8 engines
D) Both A and B

Answer 2

D

Question 3

Technician A says that the ECT and IAT sensors can be tested visually, as well as by using a digital multimeter or a scan tool. Technician B says that the ECT sensor is a high-authority sensor at engine startup and is used for open-loop control, as well as idle speed. Which technician is correct?

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

Answer 3

C

Question 4

Which of the following components provides the engine control computer with coolant temperature information?

A) TP sensor
B) MAP sensor
C) OP sensor
D) ECT sensor

Question 5

All of the following are approved methods for diagnosing a ECT (engine coolant temperature) sensor EXCEPT ________.

A) scan tool
B) observing resistance values at a specified temperature
C) digital multimeter (DMM)
D) substituting a variable resistor

Question 6

Technician A says that all temperature sensors are PTC devices that decrease in resistance as the temperature increases. Technician B says that some vehicle manufacturers use a stepped ECT circuit inside the PCM to broaden the accuracy of the sensor. Which technician is correct?

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

Question 7

Technician A says that other temperature sensors that operate like the ECT include the transmission fluid temperature (TFT), and cylinder head temperature sensor. Technician B says that all temperature sensors increase in resistance as the temperature decreases. Which technician is correct?

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

Question 8

The sensor that measures the temperature of the air being drawn into the engine is called which of these?

A) NTC thermistor
B) IAT
C) PTC thermistor
D) Both A and B

Question 9

An IAT is being tested. After the vehicle has been allowed to cool for several hours, a scan tool is used to observe the IAT sensor reading. When compared to the engine coolant temperature (ECT), the two temperatures should be within how many degrees F of each other?

A) 25
B) 10
C) 5
D) 15

Question 10

A corroded connector at the ECT could cause ________.

A) poor fuel economy
B) stored DTC
C) air-fuel mixture too rich
D) All of these

Question 11

The wiring to the IAT sensor has high resistance (cut wire). What could this cause?

A) Poor fuel economy
B) Black exhaust smoke
C) Both A and B
D) Neither A nor B

Question 12

Technician A says that the purpose of the intake air temperature (IAT) sensor is to provide the engine computer (PCM) with the temperature of the air entering the engine. Technician B says that the IAT sensor information is used for fuel control (adding or subtracting fuel) and spark timing, depending on the temperature of incoming air. Which technician is correct?

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

Question 13

In the below illustration what type of circuit is depicted?

A) Positive temperature coefficient (PTC) thermistor
B) Step-up transformer
C) Negative temperature coefficient (NTC) thermistor
D) Oxygen (O2S) sensor