Vehicle mechanical basics, checks and maintenance
What the exam tests
This domain checks that you can spot a vehicle defect before it becomes a breakdown or a crash: daily and weekly checks, dashboard warning lights, tyre condition, fluid levels and basic fault diagnosis. The questions are practical, so link each check to the consequence of neglecting it.
Daily and weekly checks
Walk around the vehicle: tyres, lights, indicators, mirrors, windscreen, wipers, number plates and leaks under the car. Weekly, check tyre pressures when cold (including the spare), engine oil, coolant, brake fluid, windscreen washer and battery terminals. Check the tread depth and look for cuts, bulges and uneven wear; worn tyres lengthen braking distances and cause aquaplaning.
Dashboard warning lights
Red means stop safely and investigate: oil pressure, brake system, coolant temperature, battery charging. Amber means check soon: engine management, ABS, tyre pressure. A flashing red brake light usually means the handbrake is on or the fluid is low. Do not ignore a red light by covering it with tape.
Fluids and mechanics
Engine oil: check on level ground with the engine off and cool enough to be safe; too little causes seizure, too much causes leaks and smoke. Coolant: never open a hot radiator cap. Brake fluid absorbs water over time and should be changed on schedule. A spongy brake pedal suggests air or a leak - stop driving. A slipping clutch shows as rising engine speed without acceleration.
Worked example
The brake pedal sinks towards the floor when held at a junction. Reasoning: this points to a hydraulic leak or air in the brake system, not to worn pads alone. The safe response is to stop, check the fluid level and call a mechanic; continuing to drive risks total brake failure.
Traps
Checking oil immediately after switching off a hot engine, overfilling oil, checking tyre pressure when tyres are hot, ignoring a red warning light, and topping up coolant with cold water on a hot engine. Another trap is assuming a spare tyre is serviceable without checking its pressure.