1 | Page
AUT-135 Final Exam Questions and Correct
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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, 2 | Page
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
© 2025 All rights reserved
, 3 | Page
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
Which of the following is NOT a spark plug thread diameter? Ans:
— 9/16 in
Which of the following may result from too little EGR flow? Ans: —
all correct
An APP [accelerator pedal position] sensor is found on vehicles
with ______. Ans: — throttle by water
On an oscilloscope, which section ends with the primary coil
current off signal? Ans: — dwell
In EI systems using one ignition coil for every two cylinders,
Technician A says two plugs fire at the same time, with one
wasting the spark on the exhaust stroke. Technician B says one
plug fires in the normal direction and the other in reversed
polarity. Who is correct? Ans: — both
An oxygen sensor must heat up to approximately _____ before
functioning in its closed loop mode. Ans: — 600 F
Technician A says diesel engines consume less fuel per mile than a
gasoline engine of the same size. Technician B says diesel engines
provide more torque than a gasoline engine of the same size. Who
is correct? Ans: — both
© 2025 All rights reserved
AUT-135 Final Exam Questions and Correct
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
© 2025 All rights reserved
, 2 | Page
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
© 2025 All rights reserved
, 3 | Page
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
Which of the following is NOT a spark plug thread diameter? Ans:
— 9/16 in
Which of the following may result from too little EGR flow? Ans: —
all correct
An APP [accelerator pedal position] sensor is found on vehicles
with ______. Ans: — throttle by water
On an oscilloscope, which section ends with the primary coil
current off signal? Ans: — dwell
In EI systems using one ignition coil for every two cylinders,
Technician A says two plugs fire at the same time, with one
wasting the spark on the exhaust stroke. Technician B says one
plug fires in the normal direction and the other in reversed
polarity. Who is correct? Ans: — both
An oxygen sensor must heat up to approximately _____ before
functioning in its closed loop mode. Ans: — 600 F
Technician A says diesel engines consume less fuel per mile than a
gasoline engine of the same size. Technician B says diesel engines
provide more torque than a gasoline engine of the same size. Who
is correct? Ans: — both
© 2025 All rights reserved
