Engine Performance Final Exam
Actual Questions and Answers 2026
Engine vacuum is being discussed. Technician A says that when the
engine is operating under light loads, engine vacuum is low.
Technician B says that engine vacuum is high when the engine is
operated under heavy loads. Who is correct? -
correct answer ✅d.
neither A nor B
Ignition spark typically occurs a few degrees _______. -
correct answer ✅a. before top dead center (BTDC)
Which of the following is NOT an advantage of an electronic spark
control system? -
correct answer ✅b. It allows lower compression ratio engines to
be as efficient as higher compression ratio engines
Air/fuel ratios are being discussed. Technician A says that when the
air fuel ratio is higher than 14.7 to 1 the engine produces more
power. Technician B says that when the air fuel ratio is lower than
14.7 to 1 the engine uses less fuel. Who is correct? -
correct answer ✅d. neither A nor B
,Engine Performance Final Exam
Actual Questions and Answers 2026
The first decision the computer makes in determining the best
operating strategy is to determine the _____. -
correct answer ✅b. engine operating mode
Catalytic converter monitors are being discussed. Technician A says
that if the converter is working, the downstream signal frequency
should mirror the upstream sensor. Technician B says that the
downstream sensor should provide a low-frequency voltage signal.
Who is correct? -
correct answer ✅b. B only
What sensor is used to detect engine misfire? -
correct answer ✅a. crankshaft position
Oxygen sensor monitors are being discussed. Technician A says the
system monitors the sensor response time as the system cycles
lean-rich-lean. Technician B says that at certain times the monitor
varies the fuel delivery and checks for heated oxygen sensor
response. Who is correct? -
correct answer ✅c. both A and B
EGR monitors are being discussed. Technician A says some EGR
system monitors EGR flow by measuring the difference in pressure
,Engine Performance Final Exam
Actual Questions and Answers 2026
as the EGR gas flows through an orifice (restriction). Technician B
says some EGR monitors measure the temperature of the EGR
outlet to determine whether there is gas flowing through the EGR
valve. Who is correct? -
correct answer ✅c. both A and B
Freeze frame data is being discussed. Technician A says erasing the
code with a scan tool will erase the corresponding freeze frame
data. Technician B says the freeze frame data is the sensor and
output status data at the instant the DTC was set. Who is correct? -
correct answer ✅c. both A and B
To read flash codes on an OBD I Chrysler-built vehicle, you must
______. -
correct answer ✅d. turn the ignition key on and off three times in
five seconds, ending with on
Which of the following sensors is NOT used by the computerized
ignition system to control ignition timing? -
correct answer ✅a. oxygen sensor
OBD II technology is being discussed. Technician A says the OBD II
system has the ability to store a freeze frame (snapshot) of the
, Engine Performance Final Exam
Actual Questions and Answers 2026
operating conditions that existed when the fault occurred.
Technician B says vehicle identification must be transmitted
automatically to the scan tool. Who is correct? -
correct answer ✅c. Both A and B
Which of the following does NOT use a magnetic pulse generator
[PM generator]? -
correct answer ✅b. throttle position sensor
The engine coolant temperature sensor helps to control all the
following EXCEPT: -
correct answer ✅a. fuel pressure
Technician A tests an MAF sensor with a scan tool by watching for
erratic changes in flow while the engine idles. Technician B checks
an MAF sensor by tapping it lightly with the handle of a screwdriver
while watching the waveform on a lab scope. Who is correct? -
correct answer ✅c. both A and B
A conventional oxygen sensor needs to be heated to ________
degrees Fahrenheit before it can produce a usable signal. -
correct answer ✅b. 750
Actual Questions and Answers 2026
Engine vacuum is being discussed. Technician A says that when the
engine is operating under light loads, engine vacuum is low.
Technician B says that engine vacuum is high when the engine is
operated under heavy loads. Who is correct? -
correct answer ✅d.
neither A nor B
Ignition spark typically occurs a few degrees _______. -
correct answer ✅a. before top dead center (BTDC)
Which of the following is NOT an advantage of an electronic spark
control system? -
correct answer ✅b. It allows lower compression ratio engines to
be as efficient as higher compression ratio engines
Air/fuel ratios are being discussed. Technician A says that when the
air fuel ratio is higher than 14.7 to 1 the engine produces more
power. Technician B says that when the air fuel ratio is lower than
14.7 to 1 the engine uses less fuel. Who is correct? -
correct answer ✅d. neither A nor B
,Engine Performance Final Exam
Actual Questions and Answers 2026
The first decision the computer makes in determining the best
operating strategy is to determine the _____. -
correct answer ✅b. engine operating mode
Catalytic converter monitors are being discussed. Technician A says
that if the converter is working, the downstream signal frequency
should mirror the upstream sensor. Technician B says that the
downstream sensor should provide a low-frequency voltage signal.
Who is correct? -
correct answer ✅b. B only
What sensor is used to detect engine misfire? -
correct answer ✅a. crankshaft position
Oxygen sensor monitors are being discussed. Technician A says the
system monitors the sensor response time as the system cycles
lean-rich-lean. Technician B says that at certain times the monitor
varies the fuel delivery and checks for heated oxygen sensor
response. Who is correct? -
correct answer ✅c. both A and B
EGR monitors are being discussed. Technician A says some EGR
system monitors EGR flow by measuring the difference in pressure
,Engine Performance Final Exam
Actual Questions and Answers 2026
as the EGR gas flows through an orifice (restriction). Technician B
says some EGR monitors measure the temperature of the EGR
outlet to determine whether there is gas flowing through the EGR
valve. Who is correct? -
correct answer ✅c. both A and B
Freeze frame data is being discussed. Technician A says erasing the
code with a scan tool will erase the corresponding freeze frame
data. Technician B says the freeze frame data is the sensor and
output status data at the instant the DTC was set. Who is correct? -
correct answer ✅c. both A and B
To read flash codes on an OBD I Chrysler-built vehicle, you must
______. -
correct answer ✅d. turn the ignition key on and off three times in
five seconds, ending with on
Which of the following sensors is NOT used by the computerized
ignition system to control ignition timing? -
correct answer ✅a. oxygen sensor
OBD II technology is being discussed. Technician A says the OBD II
system has the ability to store a freeze frame (snapshot) of the
, Engine Performance Final Exam
Actual Questions and Answers 2026
operating conditions that existed when the fault occurred.
Technician B says vehicle identification must be transmitted
automatically to the scan tool. Who is correct? -
correct answer ✅c. Both A and B
Which of the following does NOT use a magnetic pulse generator
[PM generator]? -
correct answer ✅b. throttle position sensor
The engine coolant temperature sensor helps to control all the
following EXCEPT: -
correct answer ✅a. fuel pressure
Technician A tests an MAF sensor with a scan tool by watching for
erratic changes in flow while the engine idles. Technician B checks
an MAF sensor by tapping it lightly with the handle of a screwdriver
while watching the waveform on a lab scope. Who is correct? -
correct answer ✅c. both A and B
A conventional oxygen sensor needs to be heated to ________
degrees Fahrenheit before it can produce a usable signal. -
correct answer ✅b. 750
