These instructions apply to the Ford Puma Mk2 (J2K) 2020-Present.
For other models, please choose your vehicle here.
A weak key fob is one of the most common little annoyances on the Ford Puma (2020–present) — the range drops, keyless entry gets fussy, or a “Key battery low” message pops up. The fix is a 60-second coin-cell swap. The Puma fob takes a CR2032, and it splits open with the help of the emergency blade hidden inside.
What You’ll Need
- A fresh CR2032 3 V lithium coin cell.
- The metal emergency key that lives in the fob, plus a small flat screwdriver.
Swapping the Cell
- Slide out the emergency key blade — there’s a small release catch on the back of the fob.
- Insert a small screwdriver into the slot the blade leaves and gently split the two halves / lift the cell cover.
- Lift out the old CR2032, noting it sits positive (+) side up.
- Drop in the new cell positive-up, with clean dry fingers (skin oils shorten coin-cell life).
- Click the case back together and slide the blade home.
- Press any button, then test locking and keyless entry from a normal distance.
Does the Fob Need Re-coding?
No — a battery swap doesn’t touch the fob’s programming, so it works the moment the new cell is in. Note though that on the Puma a brand-new or spare key can only be programmed with Ford diagnostic equipment — that part isn’t a DIY job, only the coin cell is.
Still Not Working?
Re-open the fob and confirm the cell is the right way up and the contacts are clean and springy. If keyless entry stays sluggish, hold the fob against the start button to start the car (Ford marks the backup position), then it usually re-syncs.
Frequently Asked Questions
What battery does the Ford Puma key use?
A single CR2032 3 V lithium coin cell — cheap and sold everywhere.
Will the car still start with a dead key battery?
Yes — hold the fob against the start button to start on the backup transponder, and use the emergency blade (behind the door-handle cap) to unlock.
Which way up does the cell go?
Positive (+) side facing up, matching the cell you took out.
My remote still won’t work with a new cell — is the fob dead?
Check orientation and contacts first. If it’s still unresponsive the fob may have an internal fault and need replacing and programming at a dealer.
To clear an oil-service reminder after maintenance, see our Puma service reset guide. For warning lights, look up the code on autodtcs.com.
Independent guide — not affiliated with Ford. Always follow your official service manual and safety precautions. Read our full disclaimer.