Automotive Servicing and Repair Units of Competency
What this domain tests
Questions here check whether you understand the logic behind routine servicing and repair tasks, not just the steps. You need a working knowledge of the main vehicle systems - engine and cooling, lubrication, fuel and air, braking, steering and suspension, electrical and starting/charging, transmission and driveline - and of the tools and measurements used to assess them. Know the purpose of a service schedule, why manufacturer specifications override guesswork, and how torque, clearance and fluid type affect outcomes.
Concepts to master
Be clear on the difference between a symptom and a cause: a low brake pedal is a symptom, air in the hydraulic circuit or a failed seal is a cause. Understand wear limits and why a component is replaced rather than adjusted. Know safe jacking and support points, correct disposal of used oil and coolant, and the reason fluids must match specification (viscosity grade, coolant chemistry, brake fluid class). Familiarity with diagnostic sequence - verify, isolate, test, confirm - earns marks.
Common traps
Questions often offer a plausible but unsafe shortcut, such as supporting a vehicle on the jack alone or reusing a drained fluid. Another trap is confusing adjustment with replacement when a wear limit is exceeded. Watch for options that ignore the manufacturer's specification, and for answers that fix a symptom without diagnosing the cause. Units and tolerances are frequently swapped - read whether a figure is a minimum or maximum.
Worked example
A brake pad is measured at 1.5 mm against a specified minimum of 2.0 mm. The trap answer is "adjust the caliper". The correct reasoning: the pad is below the wear limit, so it must be replaced, and the disc and hydraulic circuit should be checked while the vehicle is supported on stands.
Rule of thumb
Measure against the specification, replace at the limit, and never trade safety for speed.