AI tests knowledge of engines, drivetrains, brakes, cooling, lubrication, and automotive electrical systems. On the CAT-ASVAB, Auto and Shop are separate subtests but contribute to a combined AS score.
Practical knowledge of automobile technology: how engine, fuel, cooling, lubrication, electrical, brake, suspension, steering, and drivetrain systems work. The CAT-ASVAB administers Auto and Shop separately, while the paper-and-pencil ASVAB combines them into one AS subtest.
Study systems as connected chains: identify what enters a component, what the component changes, and where the output goes next. AI questions usually test a part's function, the order of an operating cycle, or the likely system involved in a basic symptom.
Know the four-stroke gasoline-engine cycle and how the main moving parts turn combustion into rotation.
Trace the path from clean air and fuel to ignition, exhaust flow, and emissions control.
Separate the cooling system, which carries away heat, from the lubrication system, which reduces friction and wear.
Learn which electrical component acts before startup and which one supplies power after the engine is running.
Focus on the parts that create friction, transfer hydraulic pressure, support weight, and control unwanted motion.
Follow engine torque through the transmission to the drive wheels and know why gear ratios change.
Open a question to review the choices, correct answer, and a short explanation.
Why: The oil pump moves pressurized oil through passages to bearings and other moving parts, reducing friction and carrying away some heat.
Why: The spark plug produces an electrical spark near the end of the compression stroke to begin combustion.
Why: Springs support the vehicle and absorb bumps; shock absorbers control the springs' repeated bouncing.
Why: The catalytic converter promotes chemical reactions that convert several harmful exhaust gases into less harmful substances. The muffler mainly reduces noise.
Why: The clutch temporarily interrupts torque flow between the engine and transmission so gears can be selected smoothly.
Engine operation: Learn the four strokes and label the piston, valves, camshaft, crankshaft, and flywheel.
Cooling and lubrication: Trace coolant and oil flow, then compare the job of each pump, filter, and heat-control part.
Fuel and exhaust: Review air and fuel delivery, gasoline vs diesel ignition, and exhaust/emissions components.
Electrical systems: Study battery, starter, alternator, ignition, and circuit-protection functions.
Chassis systems: Compare disc and drum brakes and review steering, springs, shocks, and wheel alignment terms.
Drivetrain: Trace torque through the clutch or torque converter, transmission, drive shaft, differential, and axles.
Timed review: Answer a mixed set from the practice bank at a steady pace, then restudy every missed component by function.
Start a free trial to practice Auto Information and review misses by topic.
Free ASVAB study cheat sheet
Key formulas, composite scores, and score benchmarks in one printable PDF.