These instructions apply to the Ford Mondeo Mk5 (CD391) 2014-2022. For other models, please choose your vehicle here.
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When your Ford Mondeo (Mk V, CD391, 2014–2022) only locks from close range, the key battery is flat. The Mondeo came with a fold-out (flip) remote or a keyless smart key, and they take different cells.
Which Cell You Need
- Flip / blade remote: a CR2032 coin cell.
- Keyless smart key: a CR2450 coin cell.
Check which key you have before buying.
Flip Remote
- Press the button to flick out the metal blade and use the gap to split the case.
- Swap the CR2032, matching polarity, and clip it shut.
Smart Key
- Slide the catch and remove the emergency blade.
- Prise the case open at the seam.
- Fit a new CR2450 the same way up and click it together.
After the Swap
Lock and unlock once to confirm. A battery change keeps the existing pairing — no reprogramming.
Frequently Asked Questions
What battery does a Ford Mondeo key take?
The flip remote uses a CR2032; the keyless smart key uses a CR2450.
How do I tell which I have?
If a blade flicks out at a button press it’s the flip remote (CR2032); the keyless fob with a pull-out blade uses a CR2450.
Do I need to reprogram it?
No — the key keeps its pairing through a battery change.
Smart key won’t start the car?
Hold it against the marked start-button spot to start on the transponder, then have it checked.
If the car won’t wake at all, the 12 V battery may be flat — see our Mondeo 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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