These instructions apply to the Citroën C4 Mk2 (B71) 2010-2018.
For other models, please choose your vehicle here.
A weak or dead remote on a Citroen C4 Mk2 (2010–2018) is nearly always a flat key battery. The flip key uses a single CR1620 coin cell, and the swap takes a couple of minutes.
How to replace the key fob battery on a Citroen C4 (2010–2018)
- Fold in the metal key blade so you can reach the case seam.
- Insert a coin at the notch and gently twist to separate the two halves of the case.
- Slide out the old CR1620 battery, noting which way up it sits.
- Fit the new CR1620 the same way round, observing the polarity.
- Clip the case together and check the remote locks and unlocks the car.
Handle the new cell by its edges to keep it clean. If the remote still won’t work with a fresh battery, re-synchronise it: switch the ignition on, hold the lock button for a few seconds, then switch off and remove the key.
Frequently asked questions
What battery does a Citroen C4 (2010–2018) key take?
A single 3 V CR1620 coin cell — thinner and smaller than the common CR2032.
Will the car still start with a dead key battery?
Yes. The transponder is read when you turn the key in the ignition, so the car still starts — only the remote buttons stop working until you fit a new battery.
If a key or immobiliser warning stays on, you can check the fault code on autodtcs.com.
Independent guide — not affiliated with Citroën. Always follow your official service manual and safety precautions. Read our full disclaimer.