ASVAB subject guide
Auto information
Identify common vehicle systems, components, and maintenance concepts.
Core review
What to study
- Review the purpose of engine, cooling, braking, and electrical systems.
- Connect common warning signs with the system that may be affected.
- Distinguish lubrication, starting, charging, and power-transfer roles.
Five-question review
Try original auto information questions.
Attempt each question before opening the answer and explanation.
What is the main purpose of engine oil?
- Cool the passenger compartment
- Reduce friction between moving parts
- Increase tire pressure
- Charge the battery
Reveal answer and explanation
Correct answer: Reduce friction between moving parts
Engine oil lubricates moving parts and helps limit friction and wear.
Which system slows a vehicle by applying friction at the wheels?
- Cooling system
- Brake system
- Fuel system
- Exhaust system
Reveal answer and explanation
Correct answer: Brake system
The brake system converts vehicle motion into heat through friction.
A vehicle battery primarily supplies electrical energy for:
- Starting and electrical loads
- Tire traction
- Engine lubrication
- Wheel alignment
Reveal answer and explanation
Correct answer: Starting and electrical loads
The battery powers the starter and supports electrical loads.
What does the radiator help control?
- Engine temperature
- Brake pressure
- Fuel octane
- Tire tread
Reveal answer and explanation
Correct answer: Engine temperature
The radiator transfers heat from engine coolant to the surrounding air.
Which component ignites the air-fuel mixture in a gasoline engine?
- Spark plug
- Oil filter
- Muffler
- Water pump
Reveal answer and explanation
Correct answer: Spark plug
A spark plug creates the spark that ignites the compressed mixture.
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