Question 1

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

Accepted Answer

A) True 
 B)False  False

Question 2

Explain the operation of a digital EGR valve.

Accepted Answer

The digital EGR valve contains two or three computer-controlled solenoids. A tapered valve is positioned on the lower end of each solenoid plunger. When any solenoid plunger is lifted, exhaust flows past the tapered valve into the intake. The PCM can energize one, two, or three solenoids to control exhaust flow into the intake.

Question 3

A digital pyrometer may be used to inspect catalyst operation.

Accepted Answer

A) True 
 B)False  True

Question 4

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?

Accepted Answer

Malfunctio

Question 5

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

Accepted Answer

OBD II requires that the PCM perform an

Question 6

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

Accepted Answer

Hydrocarbons (HC) are unburned

Question 7

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

Accepted Answer

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

Question 8

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

Accepted Answer

Nitrogen o

Question 9

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

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

Loose or m

Question 11

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

Accepted Answer

The answer of What is the most likely cause of...

Question 12

How does the PCM operate the EVR solenoid?

Accepted Answer

The PCM pulses the EVR solenoi

Question 13

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

Accepted Answer

The OBD II systems perform a catalyst ef

Question 14

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

Accepted Answer

A) True 
 B)False

Question 15

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

Accepted Answer

The answer of In what year was the PCV system...

Question 16

The oxidation catalyst changes HC and CO into what?

Accepted Answer

The answer of The oxidation catalyst changes HC and CO...

Question 17

What is the role of the EGR valve?

Accepted Answer

To reduce

Question 18

How does the PCM use the PFE sensor signal?

Accepted Answer

The PFE signal informs the PCM regarding

Question 19

When is the three-way catalyst most efficient?

Accepted Answer

Three-way catalysts are most e

Question 20

What does the reduction catalyst change?

Accepted Answer

It changes

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

Explain the operation of a digital EGR valve.

A digital pyrometer may be used to inspect catalyst operation.

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?

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

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

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

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

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

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

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

How does the PCM operate the EVR solenoid?

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

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

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

The oxidation catalyst changes HC and CO into what?

What is the role of the EGR valve?

How does the PCM use the PFE sensor signal?

When is the three-way catalyst most efficient?

What does the reduction catalyst change?

Emissions and Engine Performance Overview

Basic Theories

History of On-Board Diagnostics Obd

On-Board Diagnostic Scanners and Digital Storage Oscilloscopes

Computers and Input Sensors

Ignition System and Related Input Sensorsoutput Actuators Diagnosis

Fuel System and Related Input Sensorsoutput Actuators Diagnosis

Strategies of On-Board Diagnostic Continuous Monitors

Strategies of On-Board Diagnostic Non-Continuous Monitors

Im Failure Diagnosis and Five-Gas Exhaust Analysis

Filters

Exam 8: Emission Control and Evaporative Systems

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

Explain the operation of a digital EGR valve.

A digital pyrometer may be used to inspect catalyst operation.

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?

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

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

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

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

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

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

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

How does the PCM operate the EVR solenoid?

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

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

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

The oxidation catalyst changes HC and CO into what?

What is the role of the EGR valve?

How does the PCM use the PFE sensor signal?

When is the three-way catalyst most efficient?

What does the reduction catalyst change?

Emissions and Engine Performance Overview

Basic Theories

History of On-Board Diagnostics Obd

On-Board Diagnostic Scanners and Digital Storage Oscilloscopes

Computers and Input Sensors

Ignition System and Related Input Sensorsoutput Actuators Diagnosis

Fuel System and Related Input Sensorsoutput Actuators Diagnosis

Strategies of On-Board Diagnostic Continuous Monitors

Strategies of On-Board Diagnostic Non-Continuous Monitors

Im Failure Diagnosis and Five-Gas Exhaust Analysis

Filters