How to Change Battery in a BMW Key Fob? Step by step
Photo by David DINTSH on Unsplash
If your BMW key fob has started acting up, the range feels weaker, the buttons work only sometimes, or the boot won’t open, don’t worry. In most cases, it’s a simple fix: the battery needs replacing.
BMW key fobs are reliable, but their coin-cell batteries usually last only two to three years before they start losing charge.
Here’s a clear, step-by-step guide to replacing the battery in your BMW key fob, plus where to find genuine or OEM replacements in the UK.
How to Know When Your BMW Key Fob Battery Is Low
You’ll likely notice one or more of these warning signs:
The locking/unlocking range has reduced
The dashboard shows a “key fob battery low” alert
Comfort Access only works when the key is held close to the door
The small LED on older keys no longer flashes
Types of BMW Key Fobs
BMW has used several key designs over the years. Knowing your type helps you choose the correct battery:
Most F and G-generation model keys use CR2032 or CR2450 batteries, both are widely available in UK stores or online.
Step-by-Step: BMW Key Fob Battery Replacement
Step 1 – Remove the Mechanical Key
Press the small release button on the side of the key and pull out the metal insert.
This also exposes the battery cover on most modern BMW fobs.
Step 2 – Open the Battery Compartment
Use a flat plastic pry tool or a coin to gently lift the back cover. Avoid using metal screwdrivers to prevent damage or scratches.
Step 3 – Remove the Old Battery
Take note of the positive (+) side before removing it. Lift the battery gently using your fingernail or a plastic edge.
Step 4 – Insert the New Battery
Place the new CR2032 or CR2450 battery with the + side facing up. Make sure it sits flat and snug in the holder.
Step 5 – Close and Test
Snap the cover back on, reinsert the key, and test all buttons. If it doesn’t work immediately, manually lock and unlock the car once to resync it.
For Rechargeable and Display Keys
Older E-series keys use rechargeable batteries soldered onto the circuit board. These recharge while in the ignition and are not designed for replacement. If the battery fails, a full key replacement is usually more practical than soldering.
The newer BMW Display Key (found on the 7 Series and G30 5 Series) uses a built-in lithium-ion battery that charges via micro-USB. Simply plug it into a charger for 30–60 minutes when the battery is low.
When Replacing the Battery Isn’t Enough
Sometimes, a new battery doesn’t solve the issue. Over time, the internal circuit board or buttons can wear out, especially on keys that have been dropped or exposed to moisture.
If your fob still doesn’t respond after fitting a fresh battery, check the button travel and shell integrity. A cracked housing or a sticky switch can interrupt contact. In that case, replacing the shell or transferring the electronics into a new OEM casing is an easy fix.
Typical BMW Key Fob Battery and Replacement Costs (UK 2025)
Replacing the battery yourself costs just a few pounds, far cheaper than ordering a new programmed key.
Final Thoughts: A Simple Fix That Saves You Time and Money
Replacing your BMW key fob battery is quick, inexpensive, and instantly restores convenience. If you drive an older E90 or a newer G20, keeping a spare coin cell handy can save you from dealership visits or key malfunctions.
And if your key shell or internals ever need replacing, MT Auto Parts offers genuine, tested BMW key fobs and replacement shells, giving you the same quality and fit as the original, without the premium price tag.
A few minutes, a small battery, and your BMW key is back to unlocking with that familiar precision.
Disclaimer: Information in this article is for general guidance on BMW key fob battery replacement. Always check your owner’s manual for model-specific details. MT Auto Parts is an independent BMW specialist and is not affiliated with BMW AG.
