These instructions apply to the Citroën C3 Mk3 (SX) 2016-2024.
For other models, please choose your vehicle here.
A weak or dead remote on a Citroen C3 Mk3 (2016–2024) is nearly always a flat key battery. The C3 uses one of two coin cells depending on the key type, and the swap takes a couple of minutes.
How to replace the key fob battery on a Citroen C3
- If your key has a flip-out blade, release and remove it; this exposes the seam to open the case.
- Carefully prise the fob apart with a small flat screwdriver, taking care not to damage the case or touch the circuit board.
- Note which battery your key uses and lift it out:
- Standard remote / flip key: CR2032
- Keyless-entry fob: CR1620
- Fit the matching new cell the same way round, observing the polarity marked inside.
- Clip the case back together, refit the blade, and test the lock and unlock buttons.
Handle the new cell by its edges to keep it clean. If the remote still won’t work with a fresh battery, it may need re-syncing to the car.
Frequently asked questions
What battery does a Citroen C3 key take?
A CR2032 on the standard remote/flip key, or a CR1620 on the keyless-entry fob. Open yours to confirm before buying.
Will the car still start with a dead key battery?
Yes — see our separate guide on starting a C3 with a dead key fob battery. The battery only affects the remote and keyless functions, not the immobiliser transponder.
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.