AUT 135 FINAL EXAM 2025/2026
QUESTIONS AND ANSWERS 100% PASS
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
pg. 1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,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
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
pg. 2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, 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
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
pg. 3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
QUESTIONS AND ANSWERS 100% PASS
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
pg. 1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
,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
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
pg. 2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
, 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
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
pg. 3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED
