ASVAB Automotive Information Test 4 — Questions and Answers
Question 1: What is the purpose of a catalytic converter's oxygen storage capacity?
- Cool exhaust gases
- Buffer air/fuel ratio fluctuations to maintain efficient conversion (Correct answer)
- Increase exhaust flow velocity
- Filter particulate matter
Correct answer: Buffer air/fuel ratio fluctuations to maintain efficient conversion
The catalytic converter stores oxygen during lean conditions and releases it during rich conditions, smoothing out air/fuel variations to maintain optimal catalyst efficiency.
Question 2: A vehicle pulls to one side during braking. Which of the following is the MOST likely cause?
- Low power steering fluid
- A seized or sticking brake caliper on one side (Correct answer)
- Worn spark plugs
- A loose exhaust hanger
Correct answer: A seized or sticking brake caliper on one side
A seized caliper on one side applies more braking force to that wheel than the other, causing the vehicle to pull toward the side with greater braking force.
Question 3: What is engine displacement?
- The weight of all rotating engine components
- The total volume swept by all pistons in one complete revolution (Correct answer)
- The horsepower output at the crankshaft
- The combustion chamber pressure at peak power
Correct answer: The total volume swept by all pistons in one complete revolution
Engine displacement is the total volume (in liters or cubic inches) swept by all pistons moving from BDC to TDC, commonly used to describe engine size.
Question 4: Which component in the charging system converts mechanical energy from the engine into electrical energy?
- Voltage regulator
- Starter motor
- Alternator (Correct answer)
- Ignition coil
Correct answer: Alternator
The alternator is driven by a belt from the crankshaft and generates AC electricity, which is then rectified to DC to charge the battery and power vehicle systems.
Question 5: What does the term 'toe' refer to in wheel alignment?
- The vertical tilt of the wheel relative to the road
- The inward or outward angle of the tires as viewed from above (Correct answer)
- The forward or rearward tilt of the steering axis
- The height difference between front and rear suspension
Correct answer: The inward or outward angle of the tires as viewed from above
Toe describes whether the fronts of the tires point toward each other (toe-in) or away from each other (toe-out) when viewed from above, affecting tire wear and handling.
Question 6: What is the function of a vehicle's mass airflow (MAF) sensor?
- Measure exhaust oxygen content
- Measure the amount of air entering the engine to calculate fuel delivery (Correct answer)
- Control the idle air bypass valve directly
- Monitor intake manifold temperature only
Correct answer: Measure the amount of air entering the engine to calculate fuel delivery
The MAF sensor measures the mass of air flowing into the engine, allowing the ECU to calculate the correct amount of fuel to inject for the proper air/fuel ratio.
Question 7: Which type of differential allows each drive wheel to rotate at a different speed while still receiving torque?
- Locked differential
- Open differential (Correct answer)
- Transfer case
- Limited-slip differential
Correct answer: Open differential
An open differential allows the two driven wheels to rotate at different speeds (needed when cornering) while still transmitting engine torque to both wheels.
ASVAB Automotive Information Test 4
What is the purpose of a catalytic converter's oxygen storage capacity?