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AUT-135 Final Exam Questions with Detailed Verified
Answers
Technician A says an 87 octane fuel is a blend of 87 percent octane and 13 percent ethanol.
Technician B says an 87 octane fuel will experience detonation in a test engine at the same
temperatures and pressures as a sample fuel blend of 87 percent isooctane and 13 percent
heptane. Who is correct? Ans: ✓ ✓ ✓ b only
_____ emissions are caused largely by unburned fuel from the combustion chambers. Ans: ✓ ✓ ✓
HC
Which of the following should NOT be used to lubricate injector O-rings? Ans: ✓ ✓ ✓ silicone
greese
The dwell period on a modern electronic ignition system ______. Ans: ✓ ✓ ✓ increases
[lengthens] as engine RPM increases
When viewing injector patterns on a lab scope, the injector pulse end with a ______. Ans: ✓ ✓ ✓
last upward spike
Technician A says some BEVs use liquid to heat the passenger compartment. Technician B says some
BEVs use an electric resistance heater with a fan to heat the passenger compartment. Who is
correct? Ans: ✓ ✓ ✓ both
Which of the following statements is not true? Ans: ✓ ✓ ✓ A type B misfire will cause the MIL light
to flash
Trouble codes are being discussed. Technician A says that the first time the system detects a fault, a
pending code is set. Technician B says that a pending code will turn on the MIL light. Who is
correct? Ans: ✓ ✓ ✓ a only
Crankshaft sensors are being discussed. Technician A says the signal from a Hall-effect CKP cannot
be used to synchronize fuel injector timing with the engine. Technician B says some early distributor
ignition systems relied on photoelectric sensors to monitor crankshaft position. Who is correct?
Ans: ✓ ✓ ✓ b only
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Technician A says the production of CO2 is directly related to the amount of fuel consumed;
therefore, more fuel-efficient engines produce less CO2. Technician B says imposing new CAFE [fuel
economy] standards will, in effect, reduce CO2 emissions. Who is correct? Ans: ✓ ✓ ✓ both
Compressed hydrogen used in FCEVs [fuel cell electric vehicle] is stored at approximately ______
psi. Ans: ✓ ✓ ✓ 5,000
Technician A says diesel engines can be used in a hybrid powertrain. Technician B says a gasoline
engine is normally used in hybrid powertrain. Who is correct? Ans: ✓ ✓ ✓ both
A vehicle with a DTC for an engine coolant temperature out of range code is being tested. The serial
data stream shows the coolant temperature to be 198 degrees Fahrenheit. When the technician
tests the resistance between the ETC terminals, he finds infinite resistance. The specifications call
for 20 to 40 ohms at 200 degrees Fahrenheit. After the ECT is replaced and the code is erased, the
system runs normally and the code and MIL illumination do not reoccur. How is this possible? Ans:
✓ ✓ ✓ When the ECT failed, the PCM substituted a nominal ECT value that allowed the engine to
run in limp home mode; the substituted value was displayed by the scan tool
Technician A says electronic secondary air systems used on OBD-II vehicles use an electrically driven
air pump. Technician B says the check valves in the secondary air tubes prevent converter
overheating if the electric air pump fails. Who is correct? Ans: ✓ ✓ ✓ a only
Technician A says increasing the Reid vapor pressure [RVP] will help the engine start easier in cold
weather. Technician B says increasing the RVP will increase the possibility of fuel boiling [vapor lock]
in summer driving. Who is correct? Ans: ✓ ✓ ✓ both
Technician A says the inertia switch has a reset button that must be depressed for at least one
second before the pump will operate again. Technician B says the inertia switch is triggered by the
ABS control module. Who is correct? Ans: ✓ ✓ ✓ a only
Diagnostic trouble codes are being discussed. Technician A says a P0442 is a manufacturer's code
and means different things, depending on what manufacturer built the car. Technician B says that a
P0304 code is a universal code that means the same thing no matter what manufacturer built the
car. Who is correct? Ans: ✓ ✓ ✓ b only
Technician A says a three-way catalytic converter [TWC] oxidizes carbon monoxide and
hydrocarbons into carbon dioxide and water. Technician B says a TWC reduces NOx into nitrogen
and carbon dioxide. Who is correct? Ans: ✓ ✓ ✓ both
Technician A says TBI systems use top fuel-feeding injectors. Technician B says PFI systems use
bottom fuel-feeding injectors. Who is correct? Ans: ✓ ✓ ✓ neither
© Get it right 2025 Getaway - Stuvia US All rights reserved
AUT-135 Final Exam Questions with Detailed Verified
Answers
Technician A says an 87 octane fuel is a blend of 87 percent octane and 13 percent ethanol.
Technician B says an 87 octane fuel will experience detonation in a test engine at the same
temperatures and pressures as a sample fuel blend of 87 percent isooctane and 13 percent
heptane. Who is correct? Ans: ✓ ✓ ✓ b only
_____ emissions are caused largely by unburned fuel from the combustion chambers. Ans: ✓ ✓ ✓
HC
Which of the following should NOT be used to lubricate injector O-rings? Ans: ✓ ✓ ✓ silicone
greese
The dwell period on a modern electronic ignition system ______. Ans: ✓ ✓ ✓ increases
[lengthens] as engine RPM increases
When viewing injector patterns on a lab scope, the injector pulse end with a ______. Ans: ✓ ✓ ✓
last upward spike
Technician A says some BEVs use liquid to heat the passenger compartment. Technician B says some
BEVs use an electric resistance heater with a fan to heat the passenger compartment. Who is
correct? Ans: ✓ ✓ ✓ both
Which of the following statements is not true? Ans: ✓ ✓ ✓ A type B misfire will cause the MIL light
to flash
Trouble codes are being discussed. Technician A says that the first time the system detects a fault, a
pending code is set. Technician B says that a pending code will turn on the MIL light. Who is
correct? Ans: ✓ ✓ ✓ a only
Crankshaft sensors are being discussed. Technician A says the signal from a Hall-effect CKP cannot
be used to synchronize fuel injector timing with the engine. Technician B says some early distributor
ignition systems relied on photoelectric sensors to monitor crankshaft position. Who is correct?
Ans: ✓ ✓ ✓ b only
© Get it right 2025 Getaway - Stuvia US All rights reserved
, Click here for more: Scholars nexus
Technician A says the production of CO2 is directly related to the amount of fuel consumed;
therefore, more fuel-efficient engines produce less CO2. Technician B says imposing new CAFE [fuel
economy] standards will, in effect, reduce CO2 emissions. Who is correct? Ans: ✓ ✓ ✓ both
Compressed hydrogen used in FCEVs [fuel cell electric vehicle] is stored at approximately ______
psi. Ans: ✓ ✓ ✓ 5,000
Technician A says diesel engines can be used in a hybrid powertrain. Technician B says a gasoline
engine is normally used in hybrid powertrain. Who is correct? Ans: ✓ ✓ ✓ both
A vehicle with a DTC for an engine coolant temperature out of range code is being tested. The serial
data stream shows the coolant temperature to be 198 degrees Fahrenheit. When the technician
tests the resistance between the ETC terminals, he finds infinite resistance. The specifications call
for 20 to 40 ohms at 200 degrees Fahrenheit. After the ECT is replaced and the code is erased, the
system runs normally and the code and MIL illumination do not reoccur. How is this possible? Ans:
✓ ✓ ✓ When the ECT failed, the PCM substituted a nominal ECT value that allowed the engine to
run in limp home mode; the substituted value was displayed by the scan tool
Technician A says electronic secondary air systems used on OBD-II vehicles use an electrically driven
air pump. Technician B says the check valves in the secondary air tubes prevent converter
overheating if the electric air pump fails. Who is correct? Ans: ✓ ✓ ✓ a only
Technician A says increasing the Reid vapor pressure [RVP] will help the engine start easier in cold
weather. Technician B says increasing the RVP will increase the possibility of fuel boiling [vapor lock]
in summer driving. Who is correct? Ans: ✓ ✓ ✓ both
Technician A says the inertia switch has a reset button that must be depressed for at least one
second before the pump will operate again. Technician B says the inertia switch is triggered by the
ABS control module. Who is correct? Ans: ✓ ✓ ✓ a only
Diagnostic trouble codes are being discussed. Technician A says a P0442 is a manufacturer's code
and means different things, depending on what manufacturer built the car. Technician B says that a
P0304 code is a universal code that means the same thing no matter what manufacturer built the
car. Who is correct? Ans: ✓ ✓ ✓ b only
Technician A says a three-way catalytic converter [TWC] oxidizes carbon monoxide and
hydrocarbons into carbon dioxide and water. Technician B says a TWC reduces NOx into nitrogen
and carbon dioxide. Who is correct? Ans: ✓ ✓ ✓ both
Technician A says TBI systems use top fuel-feeding injectors. Technician B says PFI systems use
bottom fuel-feeding injectors. Who is correct? Ans: ✓ ✓ ✓ neither
© Get it right 2025 Getaway - Stuvia US All rights reserved
