ASE Short Answer 2 — Questions and Answers
Question 1: What component converts the rotating motion of the crankshaft into the up-and-down motion needed to open and close engine valves?
- Camshaft (Correct answer)
- Flywheel
- Harmonic balancer
- Timing belt tensioner
Correct answer: Camshaft
The camshaft lobes push the valve train to open and close valves in time with the crankshaft.
Question 2: A vehicle's brake pedal slowly sinks to the floor under steady pressure with no external leak. What is the most likely cause?
- Failing master cylinder internal seal (Correct answer)
- Worn brake pads
- Air in the lines only
- Glazed rotors
Correct answer: Failing master cylinder internal seal
A pedal that sinks with no visible leak usually means the master cylinder seals are bypassing internally.
Question 3: Which gas does a properly functioning catalytic converter help reduce by converting it into nitrogen and oxygen?
- Oxides of nitrogen (NOx) (Correct answer)
- Carbon dioxide
- Water vapor
- Argon
Correct answer: Oxides of nitrogen (NOx)
The reduction catalyst breaks NOx down into harmless nitrogen and oxygen.
Question 4: What is the correct term for the angle that, when viewed from the front, describes the inward or outward tilt of the top of the tire?
- Camber (Correct answer)
- Caster
- Toe
- Thrust angle
Correct answer: Camber
Camber is the inward (negative) or outward (positive) tilt of the wheel viewed from the front.
Question 5: An engine cranks but will not start, and there is no spark or fuel injector pulse. Which sensor failure is the most likely common cause?
- Crankshaft position sensor (Correct answer)
- Coolant temperature sensor
- Mass airflow sensor
- Oxygen sensor
Correct answer: Crankshaft position sensor
The PCM uses the crankshaft position sensor signal to fire both spark and injectors, so a failure kills both.
Question 6: What does the abbreviation 'DTC' stand for in automotive diagnostics?
- Diagnostic Trouble Code (Correct answer)
- Direct Throttle Control
- Dynamic Timing Calibration
- Drivetrain Test Cycle
Correct answer: Diagnostic Trouble Code
A DTC is the Diagnostic Trouble Code stored by the onboard computer when a fault is detected.
Question 7: When measuring battery state of charge, what open-circuit voltage typically indicates a fully charged 12-volt automotive battery?
- About 12.6 volts (Correct answer)
- About 10.5 volts
- About 14.7 volts
- About 11.0 volts
Correct answer: About 12.6 volts
A fully charged 12-volt battery at rest reads about 12.6 volts.
ASE Short Answer 2
What component converts the rotating motion of the crankshaft into the up-and-down motion needed to open and close engine valves?