You can replace a BMW key fob battery yourself in about five minutes with a coin and a fresh battery

Most BMW key fobs use a coin cell battery — usually CR2032 or CR2025 — that you can buy at any pharmacy, grocery store, or hardware store for a few dollars. The battery sits behind a removable cover on the back of the fob. You do not need special tools or a trip to the dealership. The whole job takes longer to find the battery than to install it.

The steps are the same whether your fob is a flat rectangular remote or a newer curved design. The main difference is how the cover comes off — some slide, others pop out with a coin. Once you know which type you have, the rest is straightforward.

Key Takeaways

  • BMW key fob batteries are standard coin cells (CR2032 or CR2025) sold at drugstores and supermarkets for under five dollars.
  • The battery cover on the back of the fob either slides out with a coin or pops free when you press a small tab — check your fob design first.
  • Replace the old battery with the new one facing the same direction (usually the flat side faces out), then close the cover and test the fob.
  • If the fob still does not work after a new battery, the problem is likely a worn button contact or water damage, not the battery itself.

Finding the right battery for your BMW fob

Open your fob's battery cover first to see what battery is currently inside. The battery itself is stamped with its model number — CR2032, CR2025, or occasionally CR2016. Write down that number or take a photo of it.

Take that number to any pharmacy, supermarket, or drugstore. The batteries are usually in the watch and jewelry section or near the checkout counter. A single battery costs between one and three dollars. Buy two if you want a spare on hand — they last three to four years in a key fob, so you will use it eventually.

How to open the fob cover on older BMW remotes

Older BMW key fobs (roughly 2000 to 2010) have a metal or plastic cover on the back that slides out. Look at the seam where the cover meets the body of the fob. You will see a small notch or slot on one edge.

Insert a coin — a dime or penny works — into that slot and gently twist it like you are opening a paint can. The cover will slide out toward you. Do not force it; if it does not move, you may have the wrong edge. Try the other long side of the fob.

Once the cover is out, you will see the battery sitting flat in a small metal holder. Note which side is facing up — the flat side or the raised side. This matters when you put the new battery in.

How to open the fob cover on newer BMW remotes

Newer BMW fobs (2010 and later) have a cover that pops out rather than slides. Look at the back of the fob for a small rectangular tab or button, usually on one of the short edges. This tab is often recessed slightly into the plastic.

Press that tab firmly with your fingernail or the edge of a coin. The cover will pop out slightly. Grab the edge of the cover with your fingernail and pull it the rest of the way out. Again, note which side of the battery is facing up before you remove it.

Installing the new battery

Remove the old battery from the metal holder. Place the new battery into the same holder with the same side facing up as the old one was. Usually the flat side faces outward, but check the old battery to be sure. If you put it in backward, the fob will not work.

Press the battery down gently until it sits flat in the holder. You should hear or feel a small click. Do not force it — it should sit snugly but not require pressure.

Slide or pop the cover back onto the fob. For sliding covers, line up the notch and slide it in until it clicks. For pop-out covers, align the edges and press until the cover snaps into place. The cover should sit flush with the body of the fob with no gaps.

Testing the fob and troubleshooting

Stand near your BMW and press each button on the fob — lock, unlock, trunk, panic if your model has it. You should see the lights flash on your car and hear the locks respond. If nothing happens, open the fob again and check that the battery is facing the right direction. Flip it and test again.

If the fob still does not work after you have tried the battery both ways, the problem is not the battery. The most common cause is a worn rubber button pad or corroded button contacts inside the fob. Water damage is another possibility if the fob has been dropped in water or exposed to moisture. In either case, you will need a replacement fob from BMW or a locksmith.

If only one button works and the others do not, the battery is fine — that is a sign of worn button contacts, not a dead battery. A new battery will not fix that.

Where to buy a replacement battery

You do not need to go to a BMW dealership. Any pharmacy, supermarket, or drugstore carries CR2032 and CR2025 batteries in the watch or jewelry section. Walmart, Target, CVS, Walgreens, and most grocery stores stock them. You can also order them online from Amazon or eBay if you prefer, though you will pay for shipping on a two-dollar item.

Some auto parts stores like AutoZone or O'Reilly also carry coin cell batteries, and a few will install one for you if you ask, though there is no reason to pay for installation on a five-minute job.

Frequently Asked Questions

What if I do not know which battery my BMW fob uses?

Open the fob and look at the battery itself — the model number is printed on it. If you cannot open the fob, call a BMW dealership with your vehicle's year and model, and they will tell you the battery type. You can also search online for "[your BMW year and model] key fob battery" and find the answer in seconds.

Can I use a different battery type if I cannot find the exact one?

No. CR2032, CR2025, and CR2016 are different sizes and voltages. Using the wrong one may not fit in the holder or may damage the fob's circuit. Buy the exact type that was in your fob originally.

How long does a new battery last in a BMW key fob?

A fresh battery typically lasts three to four years in normal use. If you use the fob heavily — pressing buttons dozens of times a day — it may last two to three years. If you use it lightly, it can last five years or more.

Is it safe to replace the battery myself, or should I go to the dealership?

It is completely safe to replace it yourself. You are not opening any electrical circuits or touching anything that can harm you. The only risk is putting the battery in backward, which straightforward means the fob will not work until you flip it. There is no danger to the car or the fob.

What should I do with the old battery?

Coin cell batteries contain small amounts of lithium and should not go in the trash. Most pharmacies and supermarkets have a battery recycling bin near the checkout or customer service desk. Drop it there for free. Some communities also have hazardous waste collection days where you can bring old batteries.