When I turn my car key, nothing happens: what to do?

Nothing lights up: battery first

If no dashboard light comes on when you turn the key, the headlights stay dark and the dome light doesn't react, the battery is almost certainly dead or disconnected. It's by far the most common cause, especially after a cold night or headlights left on.

Check the battery terminals: a loose clamp or one covered in whitish corrosion cuts power as surely as a dead battery. A boost with cables or a jump pack often solves it; if the battery is over five or six years old, have it tested.

Lights come on, but the engine won't crank

If the dashboard lights up but the engine stays silent, or you hear a single sharp click, look for a flashing key or car-with-padlock light. It means the immobilizer doesn't recognize your key's chip: the engine won't start regardless of the battery.

Try your spare key. If it starts the car, your usual key's chip is the problem, and an automotive locksmith can program a new key. If no key works and no immobilizer light appears, the starter or its relay is more likely: that's a mechanic's job.

The key flat-out won't turn

If the key goes in but jams, gently turn the steering wheel left and right while turning the key: the steering lock often engages when you park with the wheels turned. Also make sure the shifter is fully in P; on some cars the ignition won't turn otherwise.

If nothing works, the key or ignition cylinder is worn. Don't force it: a bent or broken key in the cylinder makes the repair much harder. A locksmith can cut a new key or repair the cylinder on site.

What about a push-button smart key?

On a push-button car, the "nothing happens" symptom often has a simple cause: the key battery is weak and the vehicle no longer detects it. The dashboard then shows a key-not-detected message. Before anything else, press the brake pedal all the way down while pushing the button: without the brake, most models refuse to start.

If the battery is the problem, manufacturers almost always provide a backup method: you hold the key fob against the start button or drop it into a specific slot in the console. Your owner's manual shows the exact spot. If the vehicle still doesn't recognize any key, it's a programming or antenna problem that an automotive locksmith can diagnose on site, without towing the car anywhere.

If your car has a push-button start and a mechanical key hidden in the fob, don't forget it exists: it opens the driver's door even when the fob battery is completely dead, which at least lets you reach the backup starting spot described above.

Cold weather, one more trap

In deep cold, a battery loses a good part of its capacity, and thickened oil makes the engine harder to turn over. A battery that seemed fine in the fall can therefore give out on the first frigid morning. If you hear the starter turning slowly before everything stops, it's almost always the battery rather than the starter or the key.

Cold also affects keys: a cracked or worn key can snap in the ignition when you force a cylinder stiffened by frost. Never pour hot water on a lock; a lock de-icer or a little warmth on the key is usually enough. And if the key breaks anyway, keep both pieces for the locksmith, because the head may still hold the chip your car needs.

Who to call for each symptom

Dead battery: a boost, your roadside assistance or a neighbour with cables. Immobilizer light or key that won't turn: an automotive locksmith, who comes with the equipment to program or repair. Starter clicking without cranking despite a good battery: a mechanic.

On the phone, describe exactly what you see and hear: lights on or not, click or silence, key turning or not. Those details let us tell you honestly whether it's a job for us or for a garage, before we travel.