Motor Vehicle Mechanics study guide
Motor Vehicle Mechanics · Work through your exam, one topic at a time.
This page is an independent study resource for candidates preparing for the City & Guilds Motor Vehicle Mechanics qualification, commonly referenced by the code 3902. It is aimed at learners and apprentices working on vehicle maintenance and repair skills, and at technicians consolidating knowledge for assessment. The exam covers the practical and theoretical foundations of motor vehicle work - engine systems, transmission, braking, steering and suspension, electrical and electronic systems, and workshop safety and tool use - though the precise assessment structure for this version could not be confirmed at the time of writing. Important: the official City & Guilds qualification page for 3902 returned a "404 Page Not Found" error when checked on 2026-11-05. As a result, no exam parameters - question count, duration, pass mark, fee, retake policy, validity period or detailed domain weightings - could be sourced, and all of these are shown as unknown pending review. Candidates should confirm current details directly with City & Guilds or their approved centre before booking. Topics on this exam: Motor Vehicle Mechanics. The Motor Vehicle Mechanics study guide has 1 section and about 441 words.
01Motor Vehicle Mechanics
Motor Vehicle Mechanics tests how a vehicle’s mechanical, hydraulic, electrical, and diagnostic systems interact, not just isolated part names. Expect questions on four-stroke operation, drivetrain power flow, braking and suspension geometry, electrical measurement, and evidence-based diagnosis. Answers should use correct units and explain system behavior. Four-stroke spark-ignition cycle: intake, compression, power, exhaust.
441 words, about 2 minMore study resources for Motor Vehicle Mechanics
- Practice questionsA four-stroke engine completes one full power cycle in how many crankshaft revolutions?
- FlashcardsStoichiometric air-fuel ratio. The mass ratio of air to fuel that gives complete combustion; approximately 14.7:1 for gasoline.
- Cheat sheetFour-stroke cycle order: intake, compression, power, exhaust - one power stroke per two crankshaft revolutions, so camshaft turns at half crank speed.
- Key termsfour-stroke cycle. The sequence of intake, compression, power, and exhaust strokes that a piston completes in two crankshaft revolutions.
- Study planList the major systems of a motor vehicle (engine, transmission, brakes, steering, suspension, electrical) and describe the primary function of each in 2–3 sentences.
- Common mistakesBoth are forced-induction devices and candidates memorise 'turbocharger' and 'supercharger' as a single lump, so the drive mechanism (exhaust-gas turbine versus belt/chain from the crankshaft) is never separated in memory.
- Exam-day guideBring the original, unexpired ID in the name you registered under.