Week #2 - Chapter 3

Question 1

As the load on an engine increases, the manifold vacuum decreases and the manifold absolute pressure ________.

Answer 1

Increases

Question 2

A TP sensor is what type of sensor?

Answer 2

Potentiometer

Question 3

Typical TP sensor voltage at idle is about ________.

Answer 3

0.5 volt or 10% of WOT TP sensor voltage

Question 4

When checking the ECT sensor with a scan tool, about what temperature should be displayed if the connector is removed from the sensor with the key on, engine off?

Answer 4

-40°F (-40°C)

Question 5

Two technicians are discussing a stepped ECT circuit. Technician A says that the sensor used for a stepped circuit is different than one used in a non-stepped circuit. Technician B says that a stepped ECT circuit uses different internal resistance inside the PCM. Which technician is correct?

Answer 5

Both Technicians A and B

Question 6

A typical NTC sensor decreases in resistance as the temperature ________.

Answer 6

Increases

Question 7

An oxygen sensor is being tested using a Min-Max on a digital meter set to read the average. A good oxygen sensor should display what reading?

Answer 7

450 mv

Question 8

A high O2S voltage could be due to ________.

Answer 8

A rich exhaust

Question 9

The voltage output of a zirconia oxygen sensor, when the exhaust stream is lean (excess oxygen), is ________.

Answer 9

Relatively low (close to 0 volts)

Question 10

The typical MAF reading on a scan tool with the engine at idle speed and normal operating temperature is ________.

Answer 10

3 to 7 grams per second

Question 11

A fuel‑injection system that does not use a sensor to measure the amount (or mass) of air entering the engine is usually called a(n) ________ type of system.

Answer 11

Speed density

Question 12

Silicon-diaphragm strain gauge, capacitor-capsule, and ceramic disc are examples of which sensors?

Answer 12

MAP sensors

Question 13

The relationship among atmospheric pressure, vacuum, and boost pressure in psi is that atmospheric pressure is measured in inches of Mercury. What is this measurement?

Answer 13

About 29.50 in. Hg

Question 14

The wires on a typical three wire TP sensor consist of a signal wire from the TP sensor to the PCM, ground, and ________ reference.

Answer 14

5 Volt

Question 15

Visual inspection, resistance, and using a scan tool to monitor the operation (reading) of the sensor as the engine operates are the three ways to test which sensors?

Answer 15

Temperature sensors

Question 16

Zirconia, titanium and wide-band are the three basic designs of which sensors?

Answer 16

Oxygen (O2) sensors

Question 17

An oxygen sensor detects oxygen levels in the exhaust by comparing the oxygen levels between the ________ and the ________.

Answer 17

Exhaust, Outside air

Question 18

Hot film, hot wire and Karman Vortex are the types of which sensors?

Answer 18

Airflow sensors

Question 19

How is a MAF sensor tested?

Answer 19

By visual inspection, output voltage/frequency and a scan tool

Question 20

A hot film MAF sensor uses a circuit that monitors the amount of current needed to keep the hot film ________ above the temperature of the incoming air .

Answer 20

70 C

Question 21

The three uses of a ________ by the PCM are to determine the load on the engine, to determine altitude for fuel and spark control, and to monitor and test for proper EGR operation.

Answer 21

MAP sensor

Question 22

Most computer-equipped engines use a ________ to signal the position of the throttle to the computer.

Answer 22

Throttle position sensor

Question 23

Coolant sensors have a very high resistance when the coolant is cold and a low resistance when the coolant is hot. This is referred to as ________.

Answer 23

Negative temperature coefficient (NTC)

Question 24

Idle air control, oxygen sensor closed loop, and idle speed are additional inputs from which sensor?

Answer 24

The ECT sensor

Question 25

What are three ways oxygen sensors can be tested?

Answer 25

By using a digital voltmeter (using min/max), a scan tool, or a scope