AUTI 132 FALL '22 MID-TERM
Carbon deposits in the combustion chamber can: act like a sponge absorb fuel vapors on the intake stroke release fuel vapors on the exhaust stroke all of the above
all of the above
On an OBD II vehicle, the MIL will turn on when: a condition that could cause emissions levels exceeding 1.5 times the FTP level is detected an input sensor is defective an output sensor is defective all of the above
all of the above
On an OBD II vehicle, when the ignition key is on and the engine is not running, the MIL should: be off be illuminated flash and then go out be flashing
be illuminated
An analog scope is less complicated and cheaper than a DSO (digital) scope. True False
True
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. True False
True
If everything in the system is functioning smoothly, both LTFT and STFT values should be close to 0. True False
True
OBD II provides a universal OBD 16-pin DLC for all manufacturers' vehicles since 1990. True False
True
OBD II regulations require vehicle manufacturers to use the same terms for the same type of components on all manufacturers' vehicles. True False
True
On an OBD II emission control system, both pre-catalyst and post-catalyst oxygen sensors are used. True False
True
Particulate matter (PM) is generally referred to as soot and smoke. True False
True
The EVAP charcoal canister functions as a storage container for fuel vapors. True False
True
The continuous monitors act as a safety gate against emission system failure that could result in increased pollutants being emitted. True False
True
An evaporative emissions system large leak or no purge flow could be caused by all of the following EXCEPT: a loose or missing crankcase oil filler cap a vapor management valve failed closed a canister vent failed in the open position a loose or missing fuel tank filler cap
a loose or missing crankcase oil filler cap
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 only B only both A and B neither A nor B
B only
While discussing digital storage oscilloscopes: Technician A says the DSO shows the signals as they occur. Technician B says the DSO reads signals, stores them, and then displays them. Who is correct? A only B only both A and B neither A nor B
B only
Technician A says diagnostic scan tester operation varies depending on the make and model of the scan tool. Technician B says one of the major differences between OBD II and OBD I scan tools is how and where they are connected to the DLC. Who is correct? A only B only both A and B neither A nor B
both A and B
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 only B only both A and B neither A nor B
both A and B
Technician A says under ideal combustion, all the nitrogen entering the combustion chamber will leave the combustion chamber unchanged. Technician B says under ideal combustion, all the oxygen and all the hydrocarbons are chemically recombined to produce carbon dioxide and water. Who is correct? A only B only both A and B neither A nor B
both A and B
While discussing OBD II systems: Technician A says if a misfire condition threatens engine or catalyst damage, the PCM flashes the MIL. Technician B says the PCM illuminates the MIL if a defect causes emission levels to exceed 1.5 times the emission standards for that model year. Who is correct? A only B only both A and B neither A nor B
both A and B
When a DTC is set, the PCM also stores the operating parameters of the emission control system at the time of the event in a data program called: freeze frame system readiness monitor diagnostic trouble code none of the above
freeze frame
Emission controls on modern vehicles produced in the United States are installed to: meet federal and state government regulations meet consumer demand meet international standards improve fuel economy
meet federal and state government regulations
Technician A says that the DLC may be located under the hood on an OBD II vehicle. Technician B says that the DLC may be located anywhere that the manufacturer chooses on an OBD II vehicle. Who is correct? A only B only both A and B neither A nor B
neither A nor B
The heated oxygen sensor monitor will test all of the following EXCEPT: sensor light off temperature sensor circuit performance sensor signal switch rate sensor heater element performance
sensor light off temperature
During perfect combustion in an internal combustion engine, the only output would be: H2O and CO2 HC and CO H2O and CO CO2 and HC
H2O and CO2
A misfire occurs when the air/fuel mixture in the combustion chamber ignites and complete combustion occurs. True False
False
OBD II does not require the inclusion of freeze frame data. True False
False
Volatile organic compounds are biodegradable and will not harm the environment. True False
False
OBD II was mandated by the Federal Environmental Protection Agency to be installed on all passenger vehicles beginning with what model year? 1990 1996 2000 2002
1996
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 only B only both A and B neither A nor B
A only
While discussing LTFT and STFT when the STFT number is -20 and the LTFT number is -20: Technician A says these numbers indicate the PCM is trying to decrease fuel delivery. Technician B says these numbers indicate a normal condition. Who is correct? A only B only both A and B neither A nor B
A only
A technician is viewing a scan tool data stream to diagnose an OBD II system. The downstream HO2S has the same voltage switching rate as the upstream HO2S. Technician A says the air/fuel ratio is too rich. Technician B says the catalytic converter may be defective. Who is correct? A only B only both A and B neither A nor B
B only
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 only B only both A and B neither A nor B
B only
Technician A says all computer system problems can be solved by using a scan tool. Technician B says many computer-controlled components can be tested with an ohmmeter or voltmeter. Who is correct? A only B only both A and B neither A nor B
B only
Technician A says not all manufacturers provide freeze frame data. Technician B says one of the mandated features of OBD II is the inclusion of freeze frame data. Who is correct? A only B only both A and B neither A nor B
B only
Technician A says one of the six principal air pollutants regulated by the EPA is nitrogen. Technician B says carbon dioxide contributes to global warming. Who is correct? A only B only both A and B neither A nor B
B only
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 only B only both A and B neither A nor B
B only
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 only B only both A and B neither A nor B
B only
If the fuel filler cap leaks, what emissions gas will be allowed to enter the atmosphere? HC CO CO2 NOX
HC
A drive cycle refers to a trip in which the operating parameters required for the PCM to run all of the OBD II emissions-related monitors have been met. True False
True
OBD II systems are highly efficient and only illuminate the malfunction indicator light (MIL) when an emissions failure has occurred that will raise emission levels 50 percent above the FTP levels. True False
True
The EGR monitor is an intrusive test, and the customer may notice an rpm fluctuation while the test is taking place. True False
True
Technician A says FTP is a test that measures emissions of HCs and CO2. Technician B says EPA is a federal agency in charge of writing and implementing policies related to environmental protection. Who is correct? A only B only both A and B neither A nor B
both A and B
Technician A says that all P1XXX DTCs are for manufacturers' specific diagnostic trouble codes. Technician B says that all P0XXX DTCs are for generic diagnostic trouble codes. Who is correct? A only B only both A and B neither A nor B
both A and B
Technician A says that nitrogen can combine in the combustion chamber with oxygen to form nitrogen oxides, a regulated air pollutant. Technician B says that nitrogen makes up 78 percent of the air that we breathe every day. Who is correct? A only B only both A and B neither A nor B
both A and B
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 only B only both A and B neither A nor B
both A and B
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 only B only both A and B neither A nor B
both A and B
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 only B only both A and B neither A nor B
both A and B
The two main categories of OBD II monitors are the: KOEO and KOER continuous and noncontinuous emissions and non-emissions related and non-related
continuous and noncontinuous
While discussing digital signals: Technician A says the leading edge of a digital signal represents a decreasing voltage. Technician B says duty cycle is the frequency at which a voltage signal occurs. Who is correct? A only B only both A and B neither A nor B
neither A nor B
When unburned hydrocarbons are exposed to oxides of nitrogen and sunlight, what is produced? particulate matter carbon monoxide both A and B photochemical smog
photochemical smog