These instructions apply to the Porsche 911 Mk8 (992) 2019-Present.
For other models, please choose your vehicle here.
When the remote on a Porsche 911 (992, 2019–present) starts working only from arm’s length, refuses to lock the car from across the car park, or throws a low-key warning in the instrument cluster, the cause is almost always the little coin cell inside the fob rather than anything wrong with the car. The 992 ships with a single style of key — the smart, keyless Porsche Entry & Drive fob shaped like a miniature ignition switch, with a hidden mechanical emergency blade — so there is just one procedure to learn. Below is exactly which cell it takes, how to open the 992’s redesigned case without marking it, and why cutting a brand-new key is the one part of this job you can’t finish at home.
How to Tell the Fob Battery Is Dying
- Shrinking range. You have to stand right beside the 911 — or almost touch the fob to the door handle — before it will lock or unlock. This is the classic first sign of a tired cell.
- Keyless Entry & Drive gets fussy. The door won’t unlock on a handle touch, or the car is slow to recognise the key when you get in and twist the switch to start. A weak cell shortens the range the car can “see” the fob at.
- A key-battery warning in the cluster. The 992’s display shows a low key-battery message when the fob voltage drops; it is the car telling you to change the cell, not a fault.
- Cold-weather dropouts. A cell that is fine on a mild day can sag below the voltage the transmitter needs on a frosty morning, so buttons work intermittently when it’s cold.
A CR2032 in a 992 fob typically lasts two to four years. If yours is around that age and showing any of the above, fit a fresh cell before you start suspecting the receiver or the immobiliser.
The Battery You Need
The 992 key uses a single CR2032 — a 3-volt lithium coin cell, 20 mm across and 3.2 mm thick. It is the most common fob battery there is, sold in any supermarket, hardware shop or phone-accessory counter. Buy a good-quality branded cell: cheap coins sag under the brief high current the transmitter pulls and can give short range even straight out of the packet. One cell does the whole job — there is only the one fob type across the 992 range.
How to Change the Battery
- Release the emergency key blade. Turn the fob over, slide the small catch, and pull the metal emergency key straight out of the body. Set it aside — you’ll slot it back last.
- Split the two case halves. With the blade removed, the shell is no longer locked together. Put a thumbnail (or a flat plastic trim tool) into the slot the blade left behind and gently peel the left and right halves apart. The 992 case separates by hand — you should not need to force or lever hard against a screw, because there isn’t one.
- Lift out the old cell. Note which way it sits before you remove it. Handle the new CR2032 by its edges — finger grease on the faces can shorten its life.
- Fit the new cell positive (+) side up, the printed “+” face towards you as the fob lies open, matching the orientation of the one you took out.
- Click the halves back together until every clip snaps home, then slide the emergency blade back in until it latches. Test all the buttons and the keyless start.
⚠️ Get the polarity right. A coin cell fitted upside-down won’t power the transmitter and can slowly discharge against the contacts — so always copy the orientation of the cell you removed rather than guessing.
Confirm It Worked
Stand back a few metres and lock, then unlock, the 911. Full range should return straight away, and Entry & Drive should unlock on a handle touch again. The key-battery message in the cluster usually clears the next time the car reads a healthy fob — sometimes instantly, sometimes after one short drive cycle rather than the moment you close the door.
If a Fresh Cell Doesn’t Fix It
- Re-check polarity and seating. An upside-down or loosely-seated cell is the single most common reason a “new” battery seems dead. The coin must sit firmly under its clip against clean contacts.
- Wipe the contacts. A smear of finger grease or a trace of corrosion on the terminals is enough to cause dropouts — clean them with a dry cloth before you blame the fob.
- Try the backup start. If the car still won’t recognise the key, hold the fob against the marked spot on the steering column (Porsche designs the 992 to read the key by proximity even with a flat cell) and start as normal — that tells you whether it’s the battery or the transmitter.
- Warning still showing? Rarely, a weak car 12 V battery can mimic key faults; if the 911 itself is slow to wake or the electronics act oddly, the vehicle battery is worth checking too.
New Key or Spare — Why It’s a Dealer Job
Swapping the coin cell keeps the fob’s existing coding, so nothing needs reprogramming and the key works the instant you reassemble it. A new key is a different matter: the 992’s immobiliser has to be accessed with Porsche’s diagnostic system, and blank Entry & Drive fobs are ordered against the car’s VIN and coded to that specific vehicle. That makes adding a spare or replacing a lost key a job for a Porsche Centre or a specialist locksmith with the right equipment — so keep the battery in your spare fresh too, and you’re never down to a single working key.
Frequently Asked Questions
What battery does a Porsche 911 (992) key fob take?
A single CR2032 3-volt lithium coin cell. Every 992 uses the same keyless Entry & Drive fob, so there is only one battery to worry about across the range.
Which way up does the cell go?
Positive (+) side up — the marked face towards you as the opened fob lies flat. To be safe, simply match the orientation of the cell you removed before it went in.
Do I need to reprogram the key after changing the battery?
No. A battery swap doesn’t touch the fob’s coding, so it pairs with the car straight away. Only a brand-new key needs coding to the vehicle.
How do I open the 992 key without breaking it?
Pull the emergency blade out first — that unlocks the shell — then peel the two halves apart by hand at the slot the blade leaves. There is no screw, so you shouldn’t need to lever hard.
How long should a 992 key battery last?
Typically two to four years. Heavy remote use, or leaving the fob sitting close to the car so the keyless system keeps waking it, shortens that.
Can I still start the car if the fob battery is completely dead?
Yes. Use the emergency blade to unlock the driver’s door, then hold the fob against the marked reader spot on the column and twist the switch — the 992 is designed to start with a flat fob, so a dead cell won’t strand you.
If the remote stopped responding suddenly — right after the car battery was disconnected, say, rather than fading gradually — the cause is more likely the pairing or a stored fault than the coin cell, and it’s worth reading any logged code on autodtcs.com before you go any further.
Independent guide — not affiliated with Porsche. Always follow your official service manual and safety precautions. Read our full disclaimer.