Car won’t start

Start with what you hear when you turn the key

The noise the car makes (or doesn’t make) narrows the problem down quickly.

Nothing at all, and the dashboard lights are dim or off

Almost always a flat battery or a loose or corroded battery terminal. If the interior light is also weak or dead, the battery is the first suspect.

A single click, or rapid clicking

Rapid clicking usually means the battery has some charge, but not enough to turn the engine. A single loud click with bright dashboard lights points more towards the starter motor or its solenoid.

The engine turns over slowly, then gives up

A weak battery, often on a cold morning or after the car has stood for a while. Older batteries struggle most in winter.

The engine turns over normally but won’t fire

The battery and starter are doing their job, so the problem is fuel, spark or security:

• Fuel: an empty or nearly empty tank (gauges can read wrong), the wrong fuel, or a failing fuel pump. If you’ve just filled up with the wrong fuel, don’t try to start it again.
• Immobiliser: a flashing key or padlock light on the dashboard means the car isn’t recognising the key. Try the spare key; a flat key fob battery is a common cause.
• Diesel in cold weather: wait for the glow plug light to go out before cranking.

The key won’t turn, or the start button does nothing

The steering lock may be engaged: turn the wheel gently left and right while turning the key. On automatics, the gear selector must be in P (or N); on manuals with a start button, press the clutch fully.

Safe checks you can do yourself

1. Make sure you’re safe first. If you’re on a busy road, get everyone out and behind the barrier, and use your hazard lights.
2. Check the dashboard: do the lights come on, and are any warning lights flashing?
3. Turn off everything electrical (lights, heater fan, radio) and try once more.
4. Don’t crank for more than about 10 seconds at a time. Wait 30 seconds between attempts so you don’t drain the battery or overheat the starter.
5. Look at the battery terminals if you can reach them safely: white or green crust, or a loose clamp, can stop the car starting.
6. Try your spare key if there’s any sign of an immobiliser problem.

Don’t: jump start a battery that is cracked, swollen, leaking or frozen; push or tow start an automatic, hybrid or electric car; or keep cranking an engine that won’t fire, which can flood it or damage the catalytic converter.

When to call a mechanic

Get help if a jump start doesn’t work, if the car starts but dies again, if the battery warning light comes on while you’re driving, or if the engine turns over normally but won’t fire. These usually need proper testing: a battery and charging test, a starter test, or a diagnostic check for fuel and ignition faults.

Many mobile mechanics can test and replace a battery or starter where the car is parked. If the car needs a workshop, a recovery service can take it to a local garage.

What a garage will do

• Test the battery’s condition and the alternator’s charging output.
• Check the starter motor, its wiring and the earth connections.
• Read fault codes for fuel, ignition and immobiliser faults.
• Explain what they found before any repair, so you can agree the work and the price.

Costs vary with the fault, the car and whether the work is done at the roadside or in a workshop. Garages set their own prices, so ask for a quote before work starts.

Frequently asked questions

Why won’t my car start when the lights work?

Lights need far less power than the starter motor. A battery can run the lights and still be too weak to turn the engine. If the engine cranks normally, the problem is more likely fuel, the immobiliser or ignition.

Can cold weather stop a car starting?

Yes. Batteries deliver less power in the cold, and engine oil is thicker, so a battery that copes in summer can fail on a frosty morning.

How long should I wait between attempts?

About 30 seconds. Cranking for long periods drains the battery and can overheat the starter motor.

Is it my battery or my starter motor?

Rapid clicking and dim lights point to the battery. A single click with bright lights points to the starter. A jump start helps tell them apart: if the car starts on a jump, the battery (or what charges it) is the likely cause.