Car Key Won't Turn in the Ignition? 6 Causes and What to Try First

You put the key in the ignition, turn it, and nothing moves. The key won't turn at all, or it goes a little way and stops dead. It's one of the most common calls an auto locksmith gets, and the good news is that the cause is often something you can fix yourself in seconds.

Below are the six causes we see most at Affordable Car Key, a mobile auto locksmith in Croydon, in the order worth checking them. Start at the top. And whatever happens, don't force the key. A key snapped off inside the ignition barrel turns a ten-second fix into a much bigger job.

1. The steering lock has engaged

This is the most common cause by a distance. When you switch off and the steering wheel moves, often because the front wheels were turned against a kerb, a pin locks the steering column. If there's pressure on that pin, the ignition cylinder can't rotate.

The fix: turn the steering wheel firmly left or right, whichever way it gives slightly, and turn the key gently at the same time. You'll usually feel both release together.

2. The gearbox isn't in Park

On an automatic, the ignition is interlocked with the gear selector. If the lever isn't fully in P, the key won't turn to start, and on many cars it won't come out either. Move the selector firmly into Park and try again. Some cars also want the brake pedal pressed.

3. The key is worn

Keys wear down. After years of use, especially with a heavy bunch of other keys swinging from the same ring, the cuts on the blade round off until they no longer lift the ignition wafers to the right height.

The test: try the spare key. If the spare turns smoothly, your main key is the problem. Get a new one cut to the car's original key code, not copied from the worn key, because a copy reproduces the wear. Our spare key cutting service cuts to code. While you're at it, take the extra keys off the ring. That weight wears the ignition barrel too.

4. The ignition barrel is worn or dirty

If the spare won't turn either, the problem is more likely inside the ignition barrel. The wafers or tumblers wear, stick or collect dirt. The early signs are a key that needs a wiggle to turn, or one that works some days and not others.

A small puff of dry graphite powder or a PTFE dry lubricant can free a sticky barrel. Avoid WD-40 and oil: they attract dust and grit and gum the barrel up further. If it's badly worn, the barrel needs repairing or replacing. That's covered on our ignition repair page.

5. The key is bent or damaged

Lay the key flat on a table next to the spare. A slight bend, often from sitting on it in a back pocket or catching it in a door, is enough to stop it turning. Don't try to straighten it with pliers. Bending the metal back weakens it, and the next turn is when it snaps. Get a replacement cut instead. If it has already broken off inside the lock, we can deal with that through broken key extraction.

6. The electronic steering lock has failed

Some cars replace the mechanical steering pin with an electronic steering lock, which a motor releases when the car recognises the key. Certain Mercedes-Benz models from the late 2000s are well known for this unit failing. The symptom is a key that goes in but won't turn, or a start button that does nothing, with no other warning. Turning the wheel won't help. The unit has to be repaired or replaced, which is a job for a specialist with the right diagnostic equipment.

What not to do

• Don't force it, hit it or use pliers on the key head.
• Don't spray oil or WD-40 into the barrel.
• Don't try keys from another car. Even a similar-looking blade can jam the wafers.

The key turns but the engine won't start?

That's a different problem. If the dashboard lights up but the engine doesn't fire, or it starts and cuts out after a second or two, the immobiliser isn't recognising the key's transponder chip. Read why transponder keys matter, or see our immobiliser reset service.

When to call a locksmith

If you've tried the steering wheel and the gear selector and the spare won't turn either, it's time to call. A worn barrel can often be repaired at the car. When it needs replacing, the new barrel can often be recoded to your existing key, so you don't end up carrying a separate key for the ignition and the doors.

Key won't turn in Croydon or South London? Call 07400 007588. There's no call-out fee, and we'll talk it through on the phone first. Sometimes the fix is the steering wheel and you won't need us at all.