Why Your Car Key Might Not Be Working — And What You Can Do About It

There’s nothing more frustrating than walking to your car, pressing the unlock button... and nothing happens. Or worse, your key turns in the ignition, but the car won’t start. If your car key isn’t working, it doesn’t always mean something major is wrong—but it’s definitely something you shouldn’t ignore.

At Car Keys in London, we’re called out daily for key issues that catch people by surprise. In this blog, we’re breaking down the most common reasons your car key might not be working, and what to do next.

1. Dead Key Fob Battery

Let’s start with the most common (and most overlooked) issue:The battery inside your key fob might be dead.

If your remote isn’t unlocking the doors or your push-start button isn’t responding, a flat battery is usually the culprit. Most key fob batteries last around 2–3 years, depending on usage.

🛠️ Solution: A quick battery replacement usually does the trick. We can replace key fob batteries on the spot with our mobile service.

2. De-Synced Key Fob

Sometimes, a key fob can lose its programming or become desynced from your car. This can happen after a battery change, power loss in the vehicle, or electronic interference.

🛠️ Solution: We can reprogram or resync your key fob to communicate with your car again—often within minutes.

3. Damaged or Worn Key Blade

If you still use a traditional or flip-style key with a blade, it can wear down over time or even bend or crack. A damaged blade might not turn in the ignition or door lock, even if everything else is working.

🛠️ Solution: We offer precise key blade cutting services to replace worn or damaged keys and get you turning the ignition smoothly again.

4. Faulty Transponder Chip

Many modern keys have a transponder chip that sends a unique signal to your car. If the chip is damaged, dislodged, or faulty, the car won’t recognize the key—meaning no start.

🛠️ Solution: We can test and replace the transponder chip or provide a new key fully programmed to your vehicle.

5. Ignition or Door Lock Problems

Sometimes the issue isn’t with the key—it’s with the ignition barrel or door lock mechanism. Wear and tear, debris, or internal faults can prevent the key from turning or being accepted.

🛠️ Solution: We can help diagnose the issue on-site and determine whether it’s the key, the lock, or both.

6. Water Damage or Physical Impact

Dropped your key in a puddle or spilled coffee on it? Even a small amount of moisture or internal damage can cause electrical failures. If your key was stepped on, crushed, or soaked—it might stop working without visible damage.

🛠️ Solution: In many cases, we can repair the key or supply a replacement and program it on the spot.

What to Do If Your Key Stops Working

If your car key suddenly stops working, don’t panic. Here's what you should do:

✅ Try your spare key – If it works, you’ve confirmed the issue is with your main key.✅ Check the battery – Especially if your car uses keyless entry or push-start.✅ Call a professional – DIY fixes can sometimes cause more harm than good.

We’re Here to Help — Anywhere in London

At Car Keys in London, we offer fast, mobile solutions across all of London and the M25. Whether it’s a dead key fob, broken blade, or reprogramming issue, we’ll come to you and sort it out—quickly and professionally.

📞 Call us now at 07577 937421 or book at www.carkeysinlondon.co.uk 🧰 On-the-spot diagnostics and key programming🚗 All car makes and models covered

Don’t let a faulty car key ruin your day. Let us get you back on the road in no time.