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Limp mode — also called limp-home mode or reduced power mode — is a protective state the engine management enters when it detects a fault serious enough to risk damage. It deliberately restricts
In most cases the battery. A fob battery typically lasts two to four years, and the failure is usually gradual — reduced range first, then intermittent operation, then nothing. The batteries are
The three differ in where the energy comes from and how much of your driving can be electric. The practical question is not how they work but which suits your journeys. A hybrid — often marketed as
Several things degrade at once, and most of them are avoidable with a little preparation. The battery is the usual first casualty. Modern cars draw a small current continuously for alarms, keyless
Because brake discs are made of cast iron, which is deliberately not corrosion-resistant, and there is nothing protecting the surface between uses. Cast iron is chosen for discs because it handles
The diesel particulate filter is clogged and the car has not been able to clean it. The filter traps soot from the exhaust, and it is designed to burn that soot off periodically — a process called
No. Engine braking is a normal, designed behaviour, and in most respects it is gentler on the car than using the brakes. Engine braking is the slowing that happens when you lift off the accelerator
Only if your car requires it or is tuned to take advantage of it. For most cars, higher-octane fuel provides no benefit and the extra cost is wasted. Octane rating does not measure energy content or
Alignment is the set of angles at which the wheels sit relative to the road and to each other. When those angles drift out of specification, the tyres are dragged rather than rolled, and they wear
Because air contracts as it cools, so the pressure inside a sealed tyre genuinely falls — no leak required. The rule of thumb is roughly 1 psi lost for every 10°F drop, or about 0.07 bar for every
A sharp squeal for a few seconds after a cold start, fading as the engine warms, is almost always the auxiliary drive belt slipping on its pulleys. It is one of the few car noises that is both very
Fog forms when moist cabin air meets glass that is below its dew point, and the water condenses out onto the surface. Which side of the glass it forms on tells you what to do, and the two cases need
Anywhere between 20,000 and 70,000 miles, which is a range wide enough to be almost useless as a guide — so the signs matter far more than the mileage. The spread is real because brake wear is
Both drive all four wheels, but they are engineered for different problems. The short version: all-wheel drive is designed for traction on roads, four-wheel drive is designed for traction off them. A
Smearing is nearly always a contamination problem rather than a worn-blade problem, which is why new wipers sometimes smear straight out of the packet. A wiper works by dragging a thin, sharp rubber
Typically 30 to 50 miles, but the honest answer is that it varies enough between models that treating it as a reliable reserve is a mistake. The light is triggered when the level in the tank falls
It is a viscosity rating — a description of how thick the oil is, at two different temperatures. Viscosity is the single most important property of engine oil, because oil that is too thick cannot
Because water is condensing inside the system and something is growing in it. The smell — usually described as damp, mouldy or like old socks — comes from bacteria and fungi colonising the
No. Idling a modern engine to warm it is a habit carried over from carburettored cars, and on a fuel-injected engine it wastes fuel, increases wear and takes longer to warm the car than simply
Vibration that appears around 50–70mph and gets worse as you accelerate is almost always a wheel balance problem. Vibration that appears only when you brake is a different fault entirely, and telling
A code such as 205/55 R16 91V describes the tyre's dimensions, construction and limits. Each part means something specific, and matching them matters more than most drivers realise. is the section
The lenses are plastic, not glass, and the outer layer has been degraded by sunlight. Almost every car built since the 1990s uses polycarbonate headlight lenses, which are light, cheap and far less
Working lights prove there is some charge, not that there is enough. Lights draw a very small current compared with a starter motor, which needs several hundred amps. A battery too weak to crank can
Both keep the crankshaft and camshaft synchronised so valves open and close in time with the pistons. The difference is material and, critically, maintenance. A timing belt is reinforced rubber. It