Deck 9: Strategies of on Board Diagnostic Continuous Monitors

Question 1

The comprehensive component monitor will use one-trip or two-trip logic when determining when to set a DTC and illuminate the MIL.

Answer 1

True

Question 2

Which of the OBD II monitors checks circuit integrity?

A) continuity detection monitor
B) comprehensive component monitor
C) short detection monitor
D) misfire monitor

Answer 2

B

Question 3

As a result of a misfire, unburned hydrocarbons (HC) are exhausted from the combustion chamber into the exhaust system, where they enter the catalytic converter.

Answer 3

True

Question 4

Technician A says the functional test observes the reaction of an output device to a command from the PCM. Technician B says with a scan tool you can access the Readiness Status menu to determine which monitors have run. Who is correct?

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

Question 5

A misfire occurs when the air/fuel mixture in the combustion chamber ignites and complete combustion occurs.

Question 6

Technician A says the comprehensive component monitor keeps track of outputs that could affect vehicle emissions. Technician B says the comprehensive component monitor performs rationality testing of the MAF sensor. Who is correct?

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

Question 7

The continuous monitors act as a safety gate against emission system failure that could result in increased pollutants being emitted.

Question 8

The continuous monitors consist of three separate monitors.

Question 9

Technician A says the comprehensive component monitor will use three-trip logic when determining when to set a DTC and illuminate the MIL. Technician B says an OBD II system requires a drive cycle to occur that meets specific enable criteria before the monitors will run to completion. Who is correct?

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

Question 10

Technician A says that the fuel system monitor checks and adjusts both short-term and long-term fuel trim. Technician B says the comprehensive component monitor looks for circuit shorts and opens. Who is correct?

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

Question 11

The PCM closely monitors the fuel delivery system through the use of the fuel monitor.

Question 12

Technician A says the comprehensive component monitor continues to run until all sensors have been tested once. Technician B says the rationality test checks to see if the input values from a sensor make sense, based on the current operating conditions at the time the test is performed. Who is correct?

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

Question 13

The continuous monitors are the catalyst efficiency, misfire, and continuous component monitors.

Question 14

A Type A misfire is a misfire that will cause emission levels to exceed 1.5 times the FTP and will set a code but will not turn on and flash the MIL until the second consecutive trip where it is detected.

Question 15

A Type B misfire is one that could cause immediate damage to the catalytic converter, and the misfire monitor will cause the MIL to flash.

Question 16

Technician A says that the engine misfire monitor is a non-continuous monitor. Technician B says that the engine misfire monitor is a continuous monitor. Who is correct?

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

Question 17

Technician A says a random misfire or a multiple cylinder misfire will be recorded as a P0300 code. Technician B says that a MIL that is flashing is an indication of an intermittent emission system failure that is not currently occurring. Who is correct?

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

Question 18

The comprehensive component monitor begins to run shortly after the vehicle is started.

Question 19

Technician A says the learned LTFT corrections are used as a new base line for STFT. Technician B says the STFT values are constantly adjusted by the PCM to correct for rich/lean running conditions. Who is correct?

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

Question 20

Technician A says the fuel system monitor may not be allowed to run if a pending code is stored. Technician B says the comprehensive component monitor will use one-trip or two-trip logic when determining when to set a DTC and illuminate the MIL, depending on the system and the detected fault. Who is correct?

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

Question 21

What values are constantly adjusted by the PCM to correct for rich/lean running conditions?

Question 22

How does the PCM detect a cylinder misfire?

Question 23

What type of tests does the comprehensive component monitor perform, and when does the it run?

Question 24

Explain what a Type A misfire is and how the PCM reacts to it.

Question 25

What type of logic does the comprehensive component monitor use when determining whether or not to set a DTC and illuminate the MIL?

Question 26

How does the PCM use short-term fuel trim (STFT) information?

Question 27

What are the basic causes of a cylinder misfire, and what adverse effect do they have on tailpipe emissions?

Question 28

When does the fuel system monitor run, and what is its role?

Question 29

Explain what the comprehensive component monitor is.

Question 30

What type of misfire could cause immediate damage to the catalytic converter and will cause the MIL to flash?

Question 31

What do rationality tests check for?

Question 32

How can a diagnostic scan tool be used to aid in performing a drive cycle, and what is a typical pattern for an OBD II drive cycle?

Question 33

Explain what Type B and Type C misfires are and what the PCM does to react to these types of misfires.

Question 34

What must the misfire monitor have the ability to do?

Question 35

What type of misfire will cause the emissions to rise above 1.5 times the design limits and will cause the misfire monitor to illuminate the MIL steady but not to flash?

Question 36

When may the fuel system monitor not be allowed to run?

Question 37

List the three separate monitors that make up the continuous monitors?

Question 38

When does the comprehensive component monitor run?

Question 39

What is long-term fuel trim (LTFT)?

Question 40

What causes a misfire to occur?