How vehicles actually work: engines, systems and service.
Auto Information measures knowledge of automotive systems and their service: the engine cycle, fuel and ignition, cooling and lubrication, brakes, tires and suspension, and vehicle electrical. Items are plain and factual - what a part does, what a symptom means, which fluid goes where - rather than diagnostic case studies.
This is a vocabulary-and-function section. You are not asked to repair anything; you are asked whether you know the difference between the radiator and the oil filter, which stroke follows compression, or what happens when tire pressure is too low. A candidate who has read a basic automotive primer does well; one who relies only on driving experience does not.
AI is not an AFQT subtest. It feeds mechanical and maintenance line scores, so its value depends entirely on the job you are aiming at - and because it is short, it is cheap to improve once you know the systems.
Section 7 of 10 in our timed mock template. This subtest is not part of the AFQT; it feeds service component and line scores used for job qualification.
The shapes below are what our bank is written against, and what the section is built around. None of them are reproduced from the official test.
Specific, not generic: what the items in this topic test, and the one or two moves that solve most of them.
Own the four-stroke cycle: intake, compression, power, exhaust, and the fact that the crankshaft turns twice per complete cycle. Know valve timing in outline, that overhead cam versus overhead valve describes where the valves are actuated, and how displacement is computed - cylinders times swept volume, so four cylinders of 450 cubic centimetres give 1800, which is 1.8 litres.
12 original questions in this topic set.
The fuel system mixes air and gasoline in a usable ratio and the ignition system supplies a spark at the right instant. Know what the air filter, fuel pump, injectors or carburettor, spark plugs, ignition coil and timing do, and the symptoms of a wrong mixture: too rich fouls plugs and wastes fuel, too lean runs hot. Understanding compression ratio and octane as knock resistance covers most items here.
10 original questions in this topic set.
Two fluid loops, two job descriptions. Cooling circulates coolant to absorb engine heat and release it through the radiator; the thermostat regulates flow by restricting it until the engine is warm, which is why a stuck thermostat can cause overheating or chronic underheating. Lubrication delivers oil to reduce friction and carry heat away; the oil filter cleans it, and low pressure - not just low level - is what damages bearings.
10 original questions in this topic set.
Hydraulic brakes multiply pedal force through the master cylinder to calipers that press pads against rotors; anti-lock systems pump the brake to keep the wheels from locking and preserve steering. For tires know the consequences of underinflation (more wear on the shoulders, more heat, worse fuel economy), the purpose of rotation and alignment, tread depth as a wet-traction factor, and the meanings of the sidewall codes.
10 original questions in this topic set.
The battery supplies current when the engine is off, the alternator recharges it and runs the electrical system once the engine is turning, and the starter draws a very large current to crank the engine. Know the fuse-and-relay pattern, why a ground matters, and the safe order for connecting and jump-starting cables.
8 original questions in this topic set.
Sampled from the Auto Information bank below, spread across its topics so you can see the range. The correct option is marked, the method is written out, and the tempting wrong options are explained - the same format you get in the app the moment you answer.
In a typical car engine, which part changes the pistons' back-and-forth motion into rotating motion?
Each piston drives a connecting rod mounted on a journal of the crankshaft, whose offset throws convert reciprocating stroke into the rotation that reaches the transmission.
On a modern port-fuel-injected engine, how does fuel enter the intake path?
Injectors open for precisely timed pulses, spraying a fine mist of fuel into the incoming air so it vaporizes and burns efficiently.
While an engine is still warming up on a cold morning, the cooling-system thermostat is doing what?
The thermostat remains closed or nearly closed while cool, keeping circulating coolant away from the radiator so the engine reaches operating temperature quickly, then opens as it heats.
In a disc brake, how is the vehicle's motion slowed?
Hydraulic pressure squeezes friction pads onto the rotor's faces; the rubbing converts kinetic energy to heat and the wheel slows.
On the clock
AI is 11 items in 7 minutes on our template - about 38 seconds each, which is comfortable for recall items. Do not linger: if a component is unfamiliar, take the most conservative functional answer and move on.
Free Auto Information practice on this site, graded instantly with explanations. Timed sections, wrong-answer review and the full library are in the app.