Deck 8: Emission Control and Evaporative Systems

Question 1

Technician A says that if the fuel tank is full on an OBD II vehicle, the EVAP monitor may not run. Technician B says that if the fuel tank is empty on an OBD II vehicle, the EVAP monitor may not run. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Answer 1

C

Question 2

Technician A says that the EGR system controls and monitors fuel vapor loss. Technician B says that the EVAP system controls and monitors fuel vapor loss. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Answer 2

B

Question 3

A digital pyrometer may be used to inspect catalyst operation.

Answer 3

True

Question 4

A defective EGR system will cause NO_X emissions to be higher than normal.

Question 5

A stuck open EGR valve pintle could cause the MIL to be illuminated and a DTC stored for "Insufficient EGR Flow."

Question 6

An aftermarket air intake system could affect emission levels.

Question 7

A PCV valve stuck in the open position may cause a lean air/fuel ratio.

Question 8

The evaporative emissions system reduces the emissions of HC vapors into the atmosphere when the vehicle:

A) is operating at highway speeds
B) is stationary and the engine is idling
C) is parked with the engine off
D) all of the above

Question 9

Technician A says the output of the air pump is directed to the area between the reduction and the oxidation catalyst. Technician B says the output of the air pump is directed to the exhaust manifolds just behind the exhaust valves. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 10

A defective EGR system could result in an engine performance complaint.

Question 11

Technician A says that the PCV is an emission control device. Technician B says that current vehicles monitor the operation of the PCV system. Who is correct?

A) A only
B) B only
C) both A and B
D) neither A nor B

Question 12

A restricted canister vent valve could cause an OBD II DTC to be stored for "Evaporative Emission Control System Incorrect Purge Flow."

Question 13

The benefits of emission controls are to:

A) reduce pollutants in the exhaust stream
B) control vapor loss into the atmosphere
C) reduce fuel consumption
D) all of the above

Question 14

Before performing an emission system diagnosis, the emission control system should be inspected for modification, tampering, and/or missing parts.

Question 15

If the catalytic converter is working properly, the outlet temperature should be lower than the inlet temperature.

Question 16

If the fuel filler cap leaks, what monitor is designed to detect the leak?

A) the catalyst efficiency monitor
B) the misfire monitor
C) the EVAP system monitor
D) none of the above

Question 17

A leaking fuel tank could cause a evaporative emission (EVAP) system to not hold pressure with the engine off.

Question 18

All of the following statements about the EGR valve are true, EXCEPT:

A) the EGR valve creates a controlled vacuum leak between the intake and exhaust manifolds
B) an EGR valve that is stuck closed will cause high NO_X emissions
C) the vacuum to many vacuum actuated EGR valves is controlled by a solenoid
D) an EGR valve that is stuck in the open position will cause detonation

Question 19

The benefits of emission control systems are to:

A) control hydrocarbon fuel vapors from escaping into the atmosphere
B) convert harmful exhaust gases into less harmful emissions before they leave the tailpipe
C) reduce fuel consumption
D) all of the above

Question 20

The EGR system is designed to reduce which exhaust emission pollutant?

A) unburned hydrocarbon
B) carbon monoxide
C) carbon dioxide
D) oxides of nitrogen

Question 21

The EGR system is designed to reduce which emission gas?

Question 22

What is the most likely cause of a catalytic converter that has been damaged by overheating?

Question 23

In the dual bed catalytic converter, which pollutant does rhodium control?

Question 24

The oxidation catalyst changes HC and CO into what?

Question 25

How does the PCM use the PFE sensor signal?

Question 26

What is the purpose of the exhaust gas recirculation system (EGR) monitor, and on what vehicles is it found?

Question 27

What is the role of the EGR valve?

Question 28

What does the reduction catalyst change?

Question 29

When is the three-way catalyst most efficient?

Question 30

Explain the construction of a modern three-way catalyst and the elements it is made of.

Question 31

An OBD II vehicle has an illuminated MIL and a stored DTC for "Catalyst Efficiency Below Threshold" and both the pre- and post-catalyst oxygen sensor signals are fluctuating between 200 mV and 800 mV. What is the most likely cause?

Question 32

How does the PCM operate the EVR solenoid?

Question 33

Which of the following is the best definition for the catalytic converter?

A) a device that produces maximum combustion inside the engine
B) a way of cleaning up the exhaust gases after they leave the engine
C) a device that creates extra oxygen to overcome exhaust gases
D) a method of emission control that is now being discontinued

Question 34

What does the three-way catalyst do, and what is the conversion efficiency of the catalyst?

Question 35

What is the catalyst efficiency monitor, and how and why is it performed?

Question 36

Why were the dual bed catalytic converters developed?

Question 37

Explain the operation of a digital EGR valve.

Question 38

In what year was the PCV system monitor added to the list of major monitors?

Question 39

What is the most common cause of an MIL illuminated for an "EVAP Gross Leak" DTC?

Question 40

Describe the operation of the PCV valve as it relates to engine speed.

Question 41

Explain the three major pollutants that are regulated vehicle emissions and their sources.