AUT-135 Final Exam Questions and Correct Answers/ Latest Update / Already Graded

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AUT-135 Final Exam Questions and
Correct Answers/ Latest Update / Already
Graded
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




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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?


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Ans: b only


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.

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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?


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