These instructions apply to the BMW 2 Series Mk2 (G42) 2021-present. For other models, please choose your vehicle here.
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When your BMW 2 Series (G42, 2021–present) key starts working only at close range, the coin cell inside is flat. It’s a five-minute swap with no reprogramming.
The Cell You Need
The G42 remote takes a single CR2032 3 V coin cell — sold everywhere. Buy one before you open the key.
Opening the Key
- Slide the catch and pull out the metal emergency blade.
- Use the blade slot to prise the back cover off the fob.
- Lift out the old CR2032, noting which way up it sits.
- Fit the new cell the same way, refit the cover and clip the blade back in.
If the Display Key Is Fitted
Higher trims may have the rechargeable Display Key — that one charges via USB or the wireless tray and has no user-replaceable cell. Charge it rather than opening it.
After the Swap
Lock and unlock once to confirm. If the standard fob still won’t respond, hold it against the wireless charging tray / start button to start, then have it checked.
Frequently Asked Questions
What battery does a BMW 2 Series key use?
The standard G42 remote uses a CR2032 coin cell.
Do I need to reprogram after changing it?
No — the key keeps its pairing through a battery change.
My key won’t start the car — what now?
Hold it against the start button or wireless tray to start on the transponder, then replace the cell.
What about the Display Key?
It’s rechargeable — charge it by USB/wireless rather than swapping a battery.
If the car won’t wake at all, the 12 V battery may be flat — see our 2 Series battery guide. For a stored code, look it up on autodtcs.com.
Disclaimer: The information on this page is provided for general guidance only. Always follow your official service manual and safety precautions when working on your vehicle. We are not responsible for errors, omissions, or any damage resulting from the use of this information.
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