These instructions apply to the DS 9 Mk1 (X) 2021-Present.
For other models, please choose your vehicle here.
When the remote for a DS 9 (2021–present) starts working only from arm’s length, ignores the first press, or dies altogether, the cause is almost always the little coin cell inside the fob rather than anything wrong with the car. The DS 9 — DS Automobiles’ EMP2-platform flagship saloon, sold across Europe as the plug-in-hybrid E-Tense and built in China — ships with a single style of key: the modern Stellantis keyless “diamond” smart fob with a hidden emergency blade. There is no separate flip-key variant to worry about, so the procedure below covers every DS 9. Here is how to spot a dying cell, the exact battery it takes, how to open the case without cracking it, and why a genuinely new key is the one job you can’t finish at home.
How to Tell the Fob Battery Is Dying
- Shrinking range. You find yourself standing right beside the car, or holding the fob against the door handle, before it will lock or unlock. This gradual loss of range is the classic first sign of a tired cell.
- Keyless entry gets fussy. On a car that normally unlocks as you touch the handle, a weak battery means the handle no longer wakes the car reliably — you end up pressing the button instead, then that starts to fail too.
- A low-key-battery message. The DS 9’s instrument cluster displays a low remote-battery warning when the fob voltage drops, so a message about the key battery is a direct prompt to change the cell.
- Cold-weather dropouts. A cell that is nearly flat struggles in low temperatures, so the fob may work in a warm garage but refuse on a frosty morning.
A coin cell in a DS 9 fob typically lasts two to four years. If yours is around that age and doing any of the above, fit a fresh battery before you start suspecting the receiver, the aerials, or the immobiliser.
The Battery You Need
The DS 9 smart key uses a single CR2032 3-volt lithium coin cell — the same 20 mm cell used across the DS and Citroën keyless range and one of the most common fob batteries there is. You’ll find it in any supermarket, hardware shop or petrol station. Fit a good-quality branded cell: cheap coin cells sag under the brief high current the transmitter draws and can give short range even when they read as “new”. Don’t be tempted by a CR2025, which looks identical but is thinner — it may not sit firmly against the contacts and can drop out.
How to Open the DS 9 Smart Key and Change the Cell
- Release the emergency blade first. Slide or press the small catch on the fob and pull the metal emergency key blade straight out. It clears the way for the case to separate and gives you a slot to work from.
- Lift the cover. Turn the fob over and locate the cover carrying the DS logo. Slip a small flat-blade screwdriver or a plastic pry tool into the seam it leaves behind and gently lever the cover up and off — work slowly around the edge so you don’t crack the plastic.
- Split the halves if needed. On this fob the two shells clip together; if the cell is still hidden, ease the same flat tool into the seam and twist just enough to part the two halves and expose the battery.
- Note the orientation, then swap the cell. Look at which way the old battery faces before you remove it. Lift the flat cell out and drop the new CR2032 in with the positive (+) side facing up, the writing visible.
- Reassemble. Press the cover back down until it clicks flush, make sure the two halves are fully closed, then slide the emergency blade back in until it latches. Test every button.
⚠️ Get the orientation right. A coin cell fitted upside down won’t power the transmitter and, left in place, can slowly discharge against the contacts — so always copy the way the old cell was sitting: positive side up.
Check It Worked
Step back a few metres and lock, then unlock, the car with the buttons; full range should return straight away. Walk up to the handle to confirm keyless entry wakes the car again. If the cluster had shown a low-key-battery message, it clears once the car next reads a healthy fob — sometimes instantly, sometimes after a drive cycle or two rather than the moment you close the case.
If a Fresh Cell Doesn’t Fix It
- Re-check polarity and seating. An upside-down or loosely seated cell is by far the most common reason a “new” battery doesn’t help. The cell must sit firmly under its clip against clean contacts.
- Wipe the contacts. A film of finger grease or a little corrosion on the terminals is enough to cause dropouts — clean them with a dry cloth before you write the fob off.
- Try the other key. If your spare fob works fine with its own battery, you’ve confirmed the car’s receiver is healthy and the fault is in the first fob.
- Weak car battery? Rarely, a flat or failing 12 V vehicle battery can mimic key faults if the car is slow to wake. If the DS 9 itself feels sluggish to power up, that’s worth checking separately.
New Key or Spare — Why It’s a Dealer Job
Changing the battery keeps the fob’s existing coding, so nothing needs reprogramming and the key works the instant you close it up. Adding a new key is a different matter. The DS 9 runs a Stellantis immobiliser, and a blank smart fob has to be ordered against the car’s VIN and then coded to the vehicle with diagnostic equipment — something only a DS dealer or a properly equipped auto-locksmith can do. That makes cutting a spare or replacing a lost key a workshop job, not a driveway one, so it pays to keep the battery in your spare fresh too and never be down to a single working key.
Frequently Asked Questions
What battery does a DS 9 key fob take?
A single CR2032 3-volt lithium coin cell. It’s the standard cell across the DS and Citroën keyless range and is sold almost everywhere.
Which way up does the battery go?
Positive (+) side facing up, with the printed markings visible. Glance at the old cell before you remove it and copy its orientation — fitting it the wrong way round means the fob simply won’t transmit.
Do I have to reprogram the DS 9 key after a battery change?
No. Swapping the cell doesn’t affect the fob’s pairing, so it works straight away. Only a brand-new key needs coding to the car.
How long should a DS 9 fob battery last?
Usually two to four years. Leaving the keyless fob sitting close to the car so it wakes constantly, or heavy use of the buttons, shortens that.
My DS 9 key still won’t work with a new battery — what now?
Re-check the cell’s polarity and that it’s seated firmly, then clean the contacts. If a known-good CR2032 still won’t bring the fob back, compare it against your spare; a failed transmitter is possible but far rarer than a simple flat or upside-down cell.
Can I still drive the DS 9 if the fob is completely dead?
Yes. Use the emergency blade hidden in the fob to unlock the driver’s door, then follow the car’s backup start procedure — keyless systems are designed to still start the car with a flat fob, typically by holding the key against a marked spot and using the start button, so a dead cell won’t strand you.
If the remote stopped responding suddenly — right after the 12 V battery was disconnected, say, rather than fading over weeks — the pairing or a stored fault is a more likely culprit than the cell; you can look up any logged code on autodtcs.com.
Independent guide — not affiliated with DS. Always follow your official service manual and safety precautions. Read our full disclaimer.