ASVAB Automotive Information Test 3 — Questions and Answers
Question 1: What is the purpose of a vehicle's PCV (Positive Crankcase Ventilation) valve?
- Regulate fuel pressure
- Vent crankcase gases back into the intake manifold (Correct answer)
- Control exhaust backpressure
- Adjust idle speed
Correct answer: Vent crankcase gases back into the intake manifold
The PCV valve routes blowby gases from the crankcase back into the intake manifold to be burned, reducing emissions and preventing oil contamination.
Question 2: Which type of valve spring arrangement uses two concentric springs in a single valve?
- Mono-leaf spring
- Dual-coil spring (Correct answer)
- Torsion spring
- Beehive spring
Correct answer: Dual-coil spring
A dual-coil (or dual) spring setup uses an inner and outer coil spring together to prevent valve float at high RPM and provide redundancy.
Question 3: What component prevents the transmission from engaging when the parking brake is not set on vehicles equipped with a brake-transmission shift interlock?
- Torque converter clutch solenoid
- Shift interlock solenoid (Correct answer)
- Neutral safety switch
- Kickdown switch
Correct answer: Shift interlock solenoid
The shift interlock solenoid physically locks the gear selector in Park unless the brake pedal is depressed, preventing accidental gear engagement.
Question 4: In a disc brake system, what is the function of the caliper piston dust boot?
- Provide extra braking force
- Keep contaminants out of the piston bore (Correct answer)
- Hold brake fluid pressure
- Center the rotor
Correct answer: Keep contaminants out of the piston bore
The dust boot is a rubber seal that covers the caliper piston to prevent dirt, moisture, and road debris from entering the piston bore and causing corrosion.
Question 5: What does a vehicle's OBD-II system primarily monitor?
- Suspension geometry
- Emission-related engine and drivetrain components (Correct answer)
- Tire pressure only
- Audio system voltage
Correct answer: Emission-related engine and drivetrain components
OBD-II (On-Board Diagnostics II) continuously monitors emission-related systems such as the engine, transmission, and exhaust to detect malfunctions and store fault codes.
Question 6: Which engine component seals combustion gases from entering the cooling system between the engine block and cylinder head?
- Valve stem seal
- Piston ring
- Head gasket (Correct answer)
- Intake manifold gasket
Correct answer: Head gasket
The head gasket seals the mating surfaces between the cylinder head and engine block, preventing combustion gases, coolant, and oil from mixing.
Question 7: What is the role of the throwout bearing (release bearing) in a manual transmission vehicle?
- Support the driveshaft
- Disengage the clutch when the pedal is pressed (Correct answer)
- Lock the flywheel during starting
- Balance the pressure plate
Correct answer: Disengage the clutch when the pedal is pressed
The throwout bearing contacts the clutch pressure plate fingers when the clutch pedal is depressed, releasing clutch pressure and disconnecting engine power from the transmission.
ASVAB Automotive Information Test 3
What is the purpose of a vehicle's PCV (Positive Crankcase Ventilation) valve?