These instructions apply to the Nissan Micra Mk5 (K14) 2017-Present.
For other models, please choose your vehicle here.
If the remote on your Nissan Micra Mk5 (K14, 2017–present) only works when you are almost touching the door handle, flashes nothing when you press a button, or throws a key warning on the dash, the cause is nearly always the tiny coin cell inside it. The K14 was sold with two different keys depending on trim — a folding remote key on entry-level cars and the Nissan Intelligent Key (the keyless smart fob) on higher grades — and although both take the same battery, they open in slightly different ways. Below is how to spot a dying cell, the exact battery to buy, the opening method for each key, and why the Micra will still start even with a completely flat fob.
How to Tell the Fob Battery Is Dying
- Shrinking range. You have to stand right next to the car, or press the button two or three times, before it locks or unlocks. This is almost always the first sign.
- No LED flash. The little indicator light on the remote stops lighting when you press a button — a quick way to confirm the fob, not the car, is at fault.
- A key-battery warning. On Intelligent Key cars the Micra shows a low key-battery message in the instrument display when the fob is weak, and keyless entry may become unreliable.
- Cold-morning dropouts. A near-flat lithium cell loses voltage in cold weather, so a fob that is fine at midday can go quiet on a frosty morning.
A coin cell in a Micra key typically lasts two to four years. If yours is around that age and behaving like the above, fit a fresh cell before you suspect the car’s receiver or immobiliser — a battery is a couple of pounds and five minutes of work.
The Battery You Need
Both the folding remote and the Intelligent Key use a single CR2032 3-volt lithium coin cell — the most common fob battery made, sold in any supermarket, chemist or hardware shop. It is worth buying a quality branded cell (Panasonic, Sony/Murata, Energizer or Duracell); very cheap cells can sag under the brief surge of current the transmitter draws and give short range even when brand new. If you are ever unsure, the safest rule is to match the code printed on the flat face of the cell you take out.
Method 1 — Intelligent Key (Keyless Smart Fob)
- Release the emergency blade. Slide the small catch on the fob and pull the mechanical key blade straight out of the body. Set it aside — you will need it to open the fob.
- Split the case. Insert a fine flat tool — a small flat-blade screwdriver, a coin, or the emergency blade itself — into the seam the blade left behind, and gently twist to part the two halves. Work slowly so you do not crack the plastic.
- Note the orientation, then lift out the old cell. Look at which way up it sits before you disturb it. The new CR2032 goes in positive (+) side up, matching the cell you removed.
- Close it up. Press the two halves back together until they click all the way round, then slide the mechanical blade home until it latches. Test every button.
Method 2 — Folding Remote Key
- Fold the metal blade closed so the fob is easier to hold, and look at the back for a small retaining screw.
- Open the case. If there is a screw, undo it with a fine cross-head (Phillips) screwdriver and lift off the cover. If you see no screw, prise the seam apart gently with a flat plastic tool.
- Swap the cell. Note how the old CR2032 sits, lift it out, and fit the new one the same way up — on the folding remote the positive (+) face points up as well.
- Reassemble. Refit the cover, drive the screw back in snugly without overtightening (the case is plastic), and check all the buttons work.
⚠️ Get the polarity right. A cell fitted the wrong way round will not power the transmitter and can slowly discharge, so the key may seem dead even with a “new” battery. Always copy the exact orientation of the cell you removed.
Confirm It Worked
Stand back a few metres and lock, then unlock, the car. Full range should return straight away, and the remote’s LED should flash cleanly on each press. On an Intelligent Key Micra, any low-key-battery message clears the next time the car reads a healthy fob — sometimes after one drive cycle rather than the instant you refit the cell.
If a Fresh Cell Doesn’t Fix It
- Re-check the polarity and seating. An upside-down or loosely seated cell is by far the most common reason a fob stays dead after a battery change.
- Wipe the contacts. A trace of finger grease or corrosion on the terminals is enough to cause dropouts — clean them with a dry cloth before deciding the fob has failed.
- Try the other key. If your spare works normally, the problem is the first fob’s electronics; if both are weak, look at the car itself.
- Rule out the car’s 12 V battery. A weak vehicle battery can make the Micra slow to wake and mimic a key fault. If the car is sluggish to respond as well, the starting battery is the more likely culprit.
New Key or Spare — Why It’s a Dealer Job
Changing the cell does not touch the fob’s coding, so no reprogramming is needed and the key works the moment you reassemble it. Adding a new key is a different matter: the blade has to be cut to the car, and a blank Intelligent Key must be paired to the Micra’s immobiliser with Nissan diagnostic equipment against the vehicle’s VIN. That makes a lost or spare key a job for a Nissan dealer or an auto-locksmith — so keep the battery in your spare fresh too, and you are never down to a single working key.
Frequently Asked Questions
What battery does a Nissan Micra Mk5 key take?
A single CR2032 3-volt lithium coin cell. Both the folding remote key and the Intelligent Key smart fob use the same size.
Which way up does the battery go?
The positive (+) face points up in both key types. The simplest safeguard is to note how the old cell sits before you remove it and fit the new one identically — a cell put in upside down will not power the fob.
Do I need to reprogram the key after changing the battery?
No. A battery swap leaves the fob’s coding untouched, so it pairs with the car straight away. Only a brand-new or replacement key needs programming.
How long should a Micra key battery last?
Usually two to four years. Frequent remote use, or leaving an Intelligent Key sitting close to the car so it keeps waking, will shorten that.
My key still won’t work after a new battery — what now?
Re-check the cell’s polarity and that it is seated firmly against clean contacts, as those cover most cases. If the LED still refuses to light with a known-good cell, the fob’s transmitter may have failed and need replacing — but that is rare next to a flat or upside-down battery.
Can I still start the Micra if the fob is completely dead?
Yes. Use the mechanical blade hidden inside the fob to unlock the driver’s door, then hold the Intelligent Key against the START/STOP button as you press it — the car reads the fob at close range even with a flat cell, so a dead battery will not strand you.
If your remote stopped working suddenly — right after the car battery was disconnected, say, rather than fading over weeks — the cause is more likely the pairing or a stored fault than the coin cell. You can look up what any related warning or stored code means over on autodtcs.com.
Independent guide — not affiliated with Nissan. Always follow your official service manual and safety precautions. Read our full disclaimer.