How to change your car key battery yourself
1. Find the right battery. Pop the old one out first or check your handbook — it’s almost always a coin cell with the code printed on top: CR2032 is the most common, CR2025 and CR2016 close behind. Any supermarket sells them.
2. Open the fob. Most fobs split along a visible seam — some have a small release slider, many need a gentle twist with a coin or the emergency key blade in a notch. Gentle is the word: plastic tabs snap, and a snapped case is a £30 job you didn’t need.
3. Swap the battery, mind the writing. Note which way the old one faces before it comes out — the engraved (+) side usually faces up. Backwards batteries are the number-one cause of “new battery, still dead”.
4. Click it shut and test both buttons from a few paces away. Done — you’ve just saved yourself a callout, and we mean that.
When it isn’t the battery
If the fresh battery changes nothing, the fault has moved up a level, and this is the part national how-to guides skip:
- The remote lost its pairing. A power drop can make the fob and car forget each other. Symptoms: buttons press fine, car ignores them. Fix: a resync — minutes of programming, small money.
- The buttons are worn out. Years of thumb-presses wear through the contact pads. Symptoms: works if you press savagely hard, one button dead before the others. Fix: new pads or case, from £30, your chip and coding kept.
- Cracked board or solder joint. Usually after a drop. Intermittent everything. Repairable more often than you’d think.
- It went through the wash. Act fast, don’t press buttons, don’t microwave it (people do), bring it to us — boards often clean up and revive.
Your reg gets you one fixed number — usually back within minutes.
Dead fob, locked car, somewhere inconvenient?
If the battery died at the worst moment and you can’t get in or get started, that’s the emergency version of this page: damage-free entry and roadside fixes across Kidsgrove, Stoke-on-Trent and North Staffordshire, 24/7, fixed price before we set off.
If a fresh battery hasn’t fixed it, the fault is usually repairable — worn buttons and tired boards are bread and butter on our key fob repair page. And if the car has genuinely stopped recognising the key, that’s a programming diagnosis, not automatically a new key.
Key battery questions, answered straight
What battery does my car key take?
Almost all fobs take a flat lithium coin cell — most commonly a CR2032, sometimes a CR2025 or CR2016. The number is printed on the old battery. They cost a pound or two from any supermarket, and yes, the £2 one works exactly like the £8 'branded for car keys' one.
I've changed the battery and my key still doesn't work — why?
The usual suspects, in order: the battery is in upside down (genuinely — check the + side); the remote lost its pairing with the car when power dropped and needs a resync; the button contacts are worn out under the rubber; or the microswitch/solder joint has cracked. The last three are locksmith jobs — a resync is minutes, a button repair is from £30 — far cheaper than the 'you need a whole new key' answer some places give.
My key battery died and now the car won't start — is the car broken?
Almost never. Most cars have an emergency start procedure for a dead fob — a hidden blade to open the door, then hold the fob against the start button or a marked spot on the steering column. Your handbook has your car's version; ring us if you're stuck and we'll talk you through it before anything else.
Do you replace car key batteries?
We do — but honestly, if a battery is genuinely all you need, do it yourself for £2 with the steps on this page. Where we earn our keep is when the new battery doesn't fix it: resyncs, worn buttons, broken cases and drowned boards, from £30 at your door.
