These instructions apply to the Renault Megane Mk4 (XFB) 2016-2022. For other models, please choose your vehicle here.
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A weak key is the usual reason a Renault Megane Mk4 (2016–2022) stops locking from a distance or makes hands-free entry unreliable. The Megane came with two key styles that take different batteries, so check which you have first.
Which Battery You Need
- Hands-free keycard (the flat card): CR2025.
- Standard remote key (with a flip blade): CR1620.
Open it and match the number on the old cell to be sure.
Hands-Free Keycard (CR2025)
- Slide the rear cover back and remove it.
- Lift out the old CR2025, noting which way up it sits.
- Fit the new cell the same way up and refit the cover.
Remote Key (CR1620)
- Use a small screwdriver to remove the key cover.
- Renew the CR1620, observing polarity.
- Refit the cover.
Lock and unlock from a few metres to confirm.
If It Still Won’t Work
- Start the car anyway — hold the keycard against the start button (or the marked spot) as you press; the car reads it directly.
- Unlock manually with the emergency blade in the driver’s door.
Frequently Asked Questions
What battery does the Renault Megane keycard take?
The hands-free keycard uses a CR2025; the standard remote key uses a CR1620.
Do I need to reprogram the key after changing the battery?
No — it pairs again as soon as power is restored.
How do I open the keycard?
Slide the rear cover off to reach the coin cell.
My keycard still won’t start the car — what now?
Hold it against the start button as you press it.
For a no-start with a warning light, check the code on autodtcs.com. See also our Megane battery guide if the car is dead.
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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