Car won't start? Common causes and what to do

Updated 22 Oct 2026

How the car behaves when you turn the key says a lot about the cause. Note exactly what happens, because it helps the mechanic or auto electrician (rewire) find the fault faster.

Nothing at all, or dim lights

Usually a flat battery or a loose or corroded battery terminal. Check that the clamps are tight and free of white or green crust. A jump start from another car often gets you going, but if the battery is old it may need replacing.

A fast clicking sound

The battery has some charge but not enough to turn the engine. Again, battery or terminals first.

One loud click, then nothing

Often the starter motor or its relay. An auto electrician can test it.

The engine turns over but won't fire

Common causes are no fuel reaching the engine (an empty tank, a failing fuel pump or a blocked filter), ignition problems, or the car's immobiliser not recognising the key. Try the spare key if you have one.

It starts, but the battery keeps going flat

The alternator may not be charging the battery, or something is draining it when the car is off. Ask an auto electrician to test the charging system before you buy a new battery.

What not to do

Don't keep cranking for long. Try for a few seconds at a time, then wait, or you'll flatten the battery and overheat the starter.
When jump-starting, connect the cables in the right order and keep them away from moving parts.

Get help

Broken down on the road? See roadside help.