Deck 10: Strategies of on Board Diagnostic Non Continuous Monitors

Question 1

The PCM continuously tests the electrical integrity of the system and monitors the EGR flow rate twice per trip.

Answer 1

False

Question 2

Technician A says that a fuel-saturated evaporative emissions canister will cause negative STFT numbers. Technician B says that a fuel-saturated evaporative emissions canister will cause negative LTFT numbers. Who is correct?

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

Answer 2

C

Question 3

During the diagnostic test procedure for a catalyst efficiency code, a diagnostic scan tool is connected to the DLC with the vehicle at operating temperature, and the data screen displays the precatalyst oxygen sensor continually switching between 200 mV - 800 mV, while the postcatalyst oxygen sensor's output voltage stays relatively steady at 700 mV. Technician A says that the postcatalyst oxygen sensor is fixed rich and should be replaced. Technician B says that the oxygen sensor readings are both normal. Who is correct?

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

Answer 3

B

Question 4

The heated oxygen sensor monitor will test all of the following EXCEPT:

A) sensor light off temperature
B) sensor circuit performance
C) sensor signal switch rate
D) sensor heater element performance

Question 5

A vehicle is brought in for repair with the complaint of poor fuel economy. A diagnostic scan tool is attached to the DLC with the vehicle at operating temperature, and the technician determines that the precatalyst oxygen sensor voltage is biased high, the injector pulse width is long, and both STFT and LTFT are high. All of the following conditions could cause this EXCEPT:

A) high fuel pressure
B) open coolant temperature sensor circuit
C) TP sensor voltage fixed high
D) MAP sensor output indicates high load condition

Question 6

To determine the efficiency of the catalytic converters, the PCM uses a complex software program and data look-up tables when the catalyst monitor is run.

Question 7

The evaporative emissions system monitor will not run if the oxygen sensor monitor failed.

Question 8

OBD II requires an EGR system monitor that will test all of the following EXCEPT:

A) EGR rpm effect
B) EGR mechanical function
C) EGR electrical function
D) EGR flow rates

Question 9

If a fault is detected during two consecutive trips, the MIL is turned on, a DTC is set, and freeze-frame data is stored.

Question 10

The EVAP charcoal canister functions as a storage container for fuel vapors.

Question 11

Technician A says the heated oxygen sensor monitor performs two distinct tests; one test verifies the performance of the pre- and post-oxygen sensor heater element and circuit. Technician B says the heated oxygen sensor monitor performs two distinct tests; one test monitors the pre- and post-oxygen sensor signal switch rate and signal circuit. Who is correct?

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

Question 12

The conventional oxidation catalyst is not capable of converting oxides of nitrogen (NO_X).

Question 13

An evaporative emissions system large leak or no purge flow could be caused by all of the following EXCEPT:

A) a loose or missing crankcase oil filler cap
B) a vapor management valve failed closed
C) a canister vent failed in the open position
D) a loose or missing fuel tank filler cap

Question 14

In order for the MIL to be extinguished, two consecutive good global trips must be seen by the PCM.

Question 15

Downstream secondary air injection systems are only used on conventional oxidation catalyst systems.

Question 16

The enhanced system must be capable of detecting a leak as small as 0.060 inch (1.5 mm).

Question 17

Technician A says the secondary air monitor tests for flow by monitoring the oxygen sensor response. Technician B says the secondary air monitor is run once per drive cycle. Who is correct?

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

Question 18

Technician A says that the EGR system monitors the ability of the fuel tank to hold pressure as well as the purge of vapors into the intake system. Technician B says that the EVAP system collects fuel vapors in the expansion cavity at the top of the fuel tank, then sends them to the charcoal canister. Who is correct?

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

Question 19

Technician A says the catalyst's ability to store and release oxygen is a direct indication of the catalyst's performance. Technician B says the catalyst monitor compares the signal from both the upstream and downstream oxygen sensors. Who is correct?

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

Question 20

The EGR monitor is an intrusive test, and the customer may notice an rpm fluctuation while the test is taking place.

Question 21

Which monitor is used to detect malfunctions that will affect engine coolant temperature and prevent the engine from reaching normal operating temperature?

Question 22

OBD II requires that the EGR system monitor test the function of what types of components and what types of flow rate?

Question 23

Explain the function of the heated oxygen sensor monitor.

Question 24

Explain the purpose of the catalyst efficiency monitor.

Question 25

Why does OBD II require oxygen sensors to be heated?

Question 26

What is indicated to the PCM if the post-oxygen sensor switches from rich to lean frequently (has a high precatalyst to postcatalyst ratio) ?

Question 27

The evaporative emission system is designed to reduce which pollutant?

Question 28

Explain the function of the evaporative emissions system monitor.

Question 29

The catalyst efficiency monitor compares the signals from what oxygen sensors?

Question 30

Why do we need an EGR valve to recirculate exhaust gases that have already gone through combustion back into the combustion chamber?

Question 31

If a non-continuous monitor system or component fails the monitor test, what will occur?

Question 32

When is the optimum time for the maximum EGR system flow rate?

Question 33

The thermostat monitor was integrated into OBD II systems beginning in what year?

Question 34

As an oxygen sensor degrades, what happens to its switch rate compared to that of a properly functioning sensor?

Question 35

Explain the function of the exhaust gas recirculation system monitor.

Question 36

What are the non-continuous monitors that are only run once per trip?

Question 37

What does OBD II call the specific conditions that must be met before each monitor will run?

Question 38

When the PCV system removes blowby gases from the engine crankcase, to what system are the removed gases directed, and what happens to the gases sent to that system?

Question 39

In what year did the EPA introduce the positive crankcase ventilation (PCV) monitor, and what is its function?

Question 40

Explain the function of the secondary air injection system monitor.