General Parts Knowledge
What the exam expects
General parts knowledge is the foundation domain: you must recognize what a component does, how it is specified, and how to match the right part to a vehicle. Expect questions on fasteners and thread types, bearings and seals, belts and hoses, filters, brake and steering components, electrical parts (batteries, alternators, starters, relays), and cooling and lubrication systems. You also need fluency with catalog lookups: VIN decoding, engine and body codes, and the difference between OEM, OES, and aftermarket parts.
Concepts to master
Know the vocabulary of fitment: year, make, model, engine, drivetrain, and production splits. Understand that a part can be mechanically interchangeable but electronically incompatible (for example, a sensor with a different connector or calibration). Learn common specifications: thread pitch, grade markings on bolt heads, hose inside diameter versus outside diameter, belt cross-sections, and filter bypass ratings. Understand the difference between a gasket and a seal, and why torque-to-yield fasteners are single-use.
Traps
Questions love look-alike parts: left versus right, with or without a sensor port, and parts that fit the base model but not a performance trim. Another trap is confusing remanufactured with rebuilt, or assuming a higher price means higher quality. Watch for questions that describe a symptom and expect you to name the failed component rather than the part to sell.
Rule of thumb
Always verify fitment with the VIN when the catalog shows a production split. If a question gives a VIN and two plausible parts, the VIN is the deciding evidence. Worked example: a customer needs a starter for a truck with two engine options; decode the VIN engine digit first, then select the starter, rather than asking the customer to guess.