These instructions apply to the Suzuki Swift Mk4 (A2L) 2017-Present.
For other models, please choose your vehicle here.
When the remote on a Suzuki Swift Mk4 (AZ, 2017–present) only locks the car from arm’s length, needs a second press, or stops responding altogether, the coin cell inside it is almost always flat. The catch on this generation is that Suzuki fitted two completely different keys depending on how the car is specified — and they take different batteries that seat the opposite way round. Cars with the keyless push-button start carry a smart remote controller that uses a CR2032; cars with an ordinary turn-key ignition and remote central locking carry a slimmer transmitter that uses a CR1616. Fit the wrong one, or the right one upside down, and the key won’t work. Here is how to tell which fob you have, the exact cell for each, and the correct orientation straight from the owner’s manual.
How to Tell the Fob Battery Is Dying
- Shrinking range. You have to be right next to the Swift — or hold the fob against the door handle — before it locks or unlocks. This is nearly always the first sign.
- Keyless entry gets fussy. On push-start cars the car stops unlocking when you grab the handle and you find yourself pressing the button on the fob instead; the engine may only start when you hold the fob right against the start switch.
- The dash flags the smart key. Push-start Swifts can show a key-shaped warning symbol or a “key” message in the cluster when the remote’s cell is weak — treat it as a prompt to change the battery, not a car fault.
- Cold-morning dropouts. A near-flat lithium cell loses voltage in the cold, so a fob that is fine at midday can fail first thing on a frosty morning.
A coin cell in a Swift key typically lasts two to four years. If yours is around that age and doing any of the above, fit a fresh cell before you suspect the receiver or immobiliser.
The Battery You Need
Which cell you need depends entirely on the key:
- Keyless push-start remote (smart key): a CR2032 3-volt lithium coin cell — the common, chunky one sold everywhere.
- Remote-only transmitter (turn-key ignition cars): a CR1616 3-volt lithium cell — the same diameter idea but much thinner. It is not interchangeable with a CR2032; forcing the wrong size in either fob will damage the contacts.
If you are not sure which you have, open the fob first and match the code printed on the cell you remove. Buy a good-quality branded cell either way — cheap coin cells sag under the brief high current the transmitter draws and can give short range even when brand new.
Method 1 — Keyless Push-Start Remote (CR2032)
- Slide out the emergency key. If your smart fob carries a mechanical blade, release its catch and pull the metal key out — it clears the way to the seam and gives you something to hold.
- Pry the case open. Wrap the tip of a small flat-bladed screwdriver in a soft cloth (to avoid scratching or shorting anything) and insert it into the slot on the fob, then gently twist to split the two halves apart.
- Note how the old cell sits, then lift it out. Fit the new CR2032 with its negative (–) terminal facing the bottom of the case, exactly as the owner’s manual specifies — that means the printed + face points up towards the back cover.
- Close the remote firmly until the halves click together, then slide the emergency key back in until it latches.
Method 2 — Remote-Only Transmitter (CR1616)
- Find the seam. The slimmer transmitter splits along the edge of its case. Insert a cloth-wrapped flat screwdriver or a fingernail into the seam.
- Twist to separate the halves gently — the case is a light plastic clamshell, so ease it apart rather than forcing it.
- Swap the cell. Lift out the old CR1616 and fit the new one so its positive (+) terminal faces the “+” mark printed inside the transmitter — note this is the opposite orientation to the push-start key above, so don’t assume.
- Clip the case shut and check the buttons.
⚠️ Discharge static before you touch the cell. Suzuki’s manual warns that static electricity from your body can damage the remote’s electronics — touch a metal surface first, and handle the fob by its edges. And get the polarity right: a cell fitted the wrong way up simply won’t power the key, and copying the orientation of the cell you removed is the surest way to avoid it.
Confirm It Worked
Stand back a few metres and lock, then unlock, the car. Full range should return straight away. On a push-start Swift, any key-warning symbol in the cluster clears once the car next reads a healthy fob — sometimes instantly, sometimes after one short drive cycle. If keyless entry was dropping out, test the door handles and the start switch from a normal distance rather than pressed against them.
If a Fresh Cell Doesn’t Fix It
- Re-check the polarity and size. The two Swift keys take different cells the opposite way up — the single most common mistake — so confirm you fitted a CR2032 negative-down (push-start) or a CR1616 positive to the “+” mark (remote-only).
- Wipe the contacts. A smear of finger grease or light corrosion on the terminals is enough to cause intermittent operation; clean them with a dry cloth and make sure the cell sits firmly under its clip.
- Rule out the car’s own battery. A weak 12-volt battery can make a Swift slow to wake and mimic a key fault. If the car itself is sluggish to respond, sort the main battery before condemning the fob.
- Still dead with a known-good cell? If the fob won’t respond at all, its transmitter may have failed — rare compared with a flat or upside-down cell, but possible.
New Key or Spare — Why It’s a Dealer Job
Changing the coin cell keeps the fob’s existing coding, so nothing needs reprogramming and the key works the moment you close it up. Adding a spare or replacing a lost key is a different story: a Swift’s immobiliser has to be accessed with diagnostic equipment to pair a new fob, and blank smart remotes must be ordered against the car’s VIN and cut to match. That makes it a job for a Suzuki dealer or an auto-locksmith — so keep the battery in your spare fresh too, and you’re never left relying on a single key.
Frequently Asked Questions
What battery does a Suzuki Swift Mk4 key take?
It depends on the key. The keyless push-start remote uses a CR2032; the remote-only transmitter on turn-key cars uses a CR1616. Both are 3-volt lithium coin cells, but they are not interchangeable, so match the code on the cell you remove.
Which way up does the battery go?
On the push-start remote the CR2032 goes in negative (–) side down — positive face up towards the cover. On the remote-only transmitter the CR1616 goes positive (+) towards the “+” mark inside the case. They’re opposite, so always copy the orientation of the old cell.
Do I need to reprogram the key after changing the battery?
No. Swapping the battery doesn’t affect the fob’s coding, so it works immediately. Only a brand-new key needs pairing to the car.
How long should a Swift key battery last?
Usually two to four years. A keyless push-start fob that lives near the car and wakes constantly, or a remote used heavily, will drain sooner.
My Swift key still won’t work after a new battery — what now?
Re-check that you used the correct cell (CR2032 vs CR1616) and fitted it the right way up, then clean the contacts. If a known-good cell still gets no response, the fob’s transmitter may have failed — but that’s uncommon next to a simple flat or reversed cell.
Can I still drive if the fob is completely dead?
Yes. Use the mechanical blade in the smart key to unlock the driver’s door, and on push-start cars you can start the engine by holding the fob against the start switch — the system is designed to work with a flat cell, so a dead battery won’t strand you.
If the remote stopped working suddenly right after the 12-volt battery was disconnected — rather than fading over weeks — the pairing, not the cell, is the more likely cause; checking for any stored fault code on autodtcs.com can tell you whether the car logged a key or immobiliser fault.
Independent guide — not affiliated with Suzuki. Always follow your official service manual and safety precautions. Read our full disclaimer.