ASE CERTIFICATION EXAM Questions
with Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
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QUESTIONS 1–50
1.
What is the primary purpose of engine oil?
A. Increase horsepower
B. Lubricate and reduce friction
C. Increase fuel combustion
D. Cool the battery
Correct Answer: B
Engine oil reduces friction and wear between moving parts.
2.
What does a catalytic converter do?
A. Increases engine power
B. Converts harmful exhaust gases into less harmful emissions
C. Increases fuel pressure
D. Cools exhaust system
Correct Answer: B
It reduces pollutants like CO, NOx, and hydrocarbons.
3.
What is the function of a crankshaft?
A. Controls fuel injection
B. Converts linear piston motion into rotational motion
,C. Compresses air
D. Controls ignition timing
Correct Answer: B
Crankshaft converts up-and-down motion into rotation.
4. (Case-Based)
A vehicle has rough idle and misfire codes P0302. Likely cause?
A. Faulty cylinder 2 ignition or fuel issue
B. Low tire pressure
C. Bad battery only
D. Exhaust leak only
Correct Answer: A
P0302 indicates misfire in cylinder 2.
5.
What does OBD-II stand for?
A. On Board Diagnostic version II
B. Off Brake Device
C. Oil Balance Detector
D. Output Brake Drive
Correct Answer: A
OBD-II is vehicle diagnostic system standard.
6.
What tool reads diagnostic trouble codes?
A. Torque wrench
B. Scan tool
C. Compression gauge
D. Timing light
Correct Answer: B
Scan tools retrieve ECU fault codes.
7.
What does a lean fuel mixture mean?
, A. Too much fuel
B. Too little fuel or excess air
C. No air flow
D. High oil pressure
Correct Answer: B
Lean means excess air compared to fuel.
8.
What is a symptom of a dead battery?
A. Engine cranks normally
B. No electrical response
C. Increased horsepower
D. High fuel economy
Correct Answer: B
Battery cannot supply electrical power.
9.
What does a spark plug do?
A. Stores fuel
B. Ignites air-fuel mixture
C. Controls oil pressure
D. Filters exhaust
Correct Answer: B
Spark plugs ignite combustion mixture.
10.
What is engine compression?
A. Fuel injection rate
B. Pressure created when piston compresses air-fuel mix
C. Exhaust flow
D. Battery voltage
Correct Answer: B
Compression is pressure before ignition.
with Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
QUESTIONS 1–50
1.
What is the primary purpose of engine oil?
A. Increase horsepower
B. Lubricate and reduce friction
C. Increase fuel combustion
D. Cool the battery
Correct Answer: B
Engine oil reduces friction and wear between moving parts.
2.
What does a catalytic converter do?
A. Increases engine power
B. Converts harmful exhaust gases into less harmful emissions
C. Increases fuel pressure
D. Cools exhaust system
Correct Answer: B
It reduces pollutants like CO, NOx, and hydrocarbons.
3.
What is the function of a crankshaft?
A. Controls fuel injection
B. Converts linear piston motion into rotational motion
,C. Compresses air
D. Controls ignition timing
Correct Answer: B
Crankshaft converts up-and-down motion into rotation.
4. (Case-Based)
A vehicle has rough idle and misfire codes P0302. Likely cause?
A. Faulty cylinder 2 ignition or fuel issue
B. Low tire pressure
C. Bad battery only
D. Exhaust leak only
Correct Answer: A
P0302 indicates misfire in cylinder 2.
5.
What does OBD-II stand for?
A. On Board Diagnostic version II
B. Off Brake Device
C. Oil Balance Detector
D. Output Brake Drive
Correct Answer: A
OBD-II is vehicle diagnostic system standard.
6.
What tool reads diagnostic trouble codes?
A. Torque wrench
B. Scan tool
C. Compression gauge
D. Timing light
Correct Answer: B
Scan tools retrieve ECU fault codes.
7.
What does a lean fuel mixture mean?
, A. Too much fuel
B. Too little fuel or excess air
C. No air flow
D. High oil pressure
Correct Answer: B
Lean means excess air compared to fuel.
8.
What is a symptom of a dead battery?
A. Engine cranks normally
B. No electrical response
C. Increased horsepower
D. High fuel economy
Correct Answer: B
Battery cannot supply electrical power.
9.
What does a spark plug do?
A. Stores fuel
B. Ignites air-fuel mixture
C. Controls oil pressure
D. Filters exhaust
Correct Answer: B
Spark plugs ignite combustion mixture.
10.
What is engine compression?
A. Fuel injection rate
B. Pressure created when piston compresses air-fuel mix
C. Exhaust flow
D. Battery voltage
Correct Answer: B
Compression is pressure before ignition.
