Renault Key Battery Replacement: How to Do It, Model by Model

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Renault key battery replacement takes about ten minutes: open the key card or remote, fit a new coin cell (a flat, button-shaped battery) with the same code, the right way round, and close it again. The signal Renault gives is the dashboard message “Key card battery low”.

Common symptoms and causes of a flat Renault key battery

• The message “Key card battery low” appears on the dashboard (Clio 4 and 5, Captur 2, Megane 4, Scenic 4, Kadjar, Trafic 3).
• On the Clio 3 phase 2, the message reads “Card battery needs changing”.
• The card or remote no longer locks or opens the car, or you have to stand closer: a weak battery shortens the signal range.
• When you start the car, the dashboard shows “Place card on reader + START” or “Hold card near START + press”.
• Causes unrelated to the battery: another device transmitting on the same frequency (a mobile phone), an area with strong electromagnetic radiation, a flat 12 V car battery, or a card that has lost synchronisation.

When a key stops responding, Renault advises changing the battery first, then going to a workshop if the problem continues. Its handbooks give the battery a life of about two years. Unofficial guides suggest replacing it every one to two years.

Before you start

A hands-free key card (it opens and starts the car while it stays in your pocket) is flat and has no blade.

A remote key has a metal blade. You need a small flat screwdriver for the remote key, or a coin on the Clio 3 phase 2. The card opens without tools.

Stay close to the car: the card is reset by four button presses near the vehicle. Do not touch the circuit board or the contacts of the card or the cover.

Good to know: a flat battery does not stop you locking, opening or starting the car. The method is in “If nothing works”.

Warning: keep coin cells out of the reach of children, new or used. A swallowed battery causes severe internal burns within hours: call 999 or 112 in the UK, or 112 elsewhere in Europe, straight away. Take used batteries to a collection point.

Warning: never pierce, bend or heat a lithium battery. A swollen battery must not be reused and goes to a collection point. Work on a non-flammable surface.

Warning: forcing the case open can void the warranty, so check the warranty end date first. A broken case or clips means a new housing, and a new key must be initialised by a Renault dealer.

Step 1: identify your Renault key and its battery

Renault describes four ways of opening a key. Your key type and model decide which one applies to you.

1. Find your key type in the table: a flat card without a blade, or a remote key with a blade.
2. If your model is not listed (Megane 3, Zoe, Austral and others), open your vehicle handbook at the chapter on the key or card.
3. Open the key or card (step 2), then read the code engraved on the old battery or printed inside the cover.
4. Get a new battery with the same code or an equivalent one; Renault dealers sell them.

You now know how your key opens and which battery it takes.

Good to know: Renault does not name a battery type in its handbooks. According to a parts reseller and members of the Renault community, the cards of the Clio 4 and 5, Megane, Captur, Kadjar, Scenic and Zoe often use a CR2032, while other generations are said to use a CR2016 or CR2025. Only the code on your own battery counts.

If your battery is a CR2032, here is where to find a new one.

Duracell CR2032 pile bouton lithium 3 V

Pile bouton lithium 3 V de référence CR2032, courante dans les cartes et clés de voiture. Vendue en lot de 4.

• AmazonSee at Amazon

Step 2: open the key or card

The marks mentioned (zone A, tab) refer to the diagrams in your handbook.

Tip: work over a table, not inside the car. A coin cell that slips between the seats is hard to find, and it stays within a child’s reach.

Card of a Clio 5, Captur 2, Megane 4, Scenic 4 or Kadjar

1. Press zone A of the rear shell and slide the shell downwards.
2. Take out the emergency key, which comes free with the shell.
3. Remove the battery cover.

Card of a Clio 4 or Trafic 3

1. Press the button on the card while pulling out the emergency key.
2. Unclip the cover using the tab.

RENAULT card of a Clio 3 phase 2

1. Pull firmly on the emergency key to take it out of the card.

The battery is now visible in its housing. Its type and polarity are marked on the emergency key.

Remote key with blade

1. Undo the cover screw if your key has one (Clio 3 phase 2, remotes A and B of the Trafic 3, some other models).
2. Except for remotes A and B of the Trafic 3, open the case at its slot with a flat screwdriver, or with a coin on the Clio 3 phase 2.

On the Trafic 3, the cover of remotes A and B comes off as soon as the screw is out. Remote C opens at its slot. In every case the battery is then visible in its housing.

Step 3: replace the battery the right way round

Warning: Renault points out a risk of explosion if the battery is fitted the wrong way. Check the direction before closing.

Tip: photograph the battery in place before you remove it. When you refit, you will see which way the + faces, even if the marking on the cover is hard to read.

1. Find the polarity marked in the card cover, or engraved in the bottom of the remote key cover.
2. Clio 4 or 5, Captur 2, Megane 4, Scenic 4, Kadjar or Trafic 3 card: remove the old battery by pressing on one edge and lifting it by the opposite edge.
3. Remote key, or RENAULT card of a Clio 3 phase 2: take the old battery out of its housing.
4. Compare the code engraved on the old battery with the one on the new battery.
5. Check that the new battery has no ink marks, which would spoil the electrical contact.
6. Fit the new battery in its housing with the polarity respected, without touching the circuit board or the contacts.
7. Keep the old battery out of children’s reach until you take it to a collection point.

The new battery is in place, with its + sign facing as the marking on the cover shows.

If your battery is a CR2025, here is where to find a new one.

Varta CR2025 pile bouton lithium 3 V

Pile bouton lithium 3 V de référence CR2025, utilisée dans certaines clés et télécommandes de voiture. Vendue en lot de 2.

• AmazonSee at Amazon

Step 4: close the key and test it

1. Refit the battery cover, then the cover or shell, in the reverse order of removal.
2. Check that the cover is clipped in properly.
3. Refit the cover screw if your remote key has one.
4. Put the emergency key back in the card.
5. Clio 4, Clio 5, Captur 2, Megane 4, Scenic 4, Kadjar or Trafic 3 card: near the vehicle, press one of the card buttons four times.
6. Start the vehicle and check that the “Key card battery low” message has gone from the dashboard.

Nothing to do on the Clio 3 phase 2: the “Card battery needs changing” message disappears after the battery change. For a remote key, the Master 4 and Clio 5 handbooks describe no reset. Unofficial guides also suggest trying the lock, the remote opening and the boot.

Warning: if the cover no longer closes properly, stop using the key or card and keep it out of children’s reach, as Renault requires.

Good to know: forums describe a reset by opening and closing the car five times. Renault handbooks give four presses of a card button. Follow that method.

If nothing works

The emergency key inside the card opens the driver’s door. It is also what you use when the car’s 12 V battery is flat (Megane 4 phase 2, Captur 2).

Starting the car with a flat card battery

On the Clio 5, Captur 2 and Megane 4 phase 2, the dashboard shows “Place card on reader + START”.

1. Press the brake or clutch pedal.
2. Place the card, buttons facing up, on the card reader area (about 2 seconds on the Megane 4 phase 2).
3. Press START.

On the 2018 Megane 4, Scenic 4 and Kadjar, hold the card near the START button until the message “Hold card near START + press” goes out. Then press START within about 2 seconds. On the Clio 4, insert the card in the card reader.

Locking the car without the card on a Clio 4 or Clio 5

1. Switch off the engine and open a door.
2. Hold the interior locking switch down for more than 5 seconds.
3. Close the door: the whole vehicle locks.

To get back in from outside you then need the card or the key. With the engine running, the card neither locks nor opens the car: switch off the ignition before locking again.

When to see a Renault workshop

On the Megane 4 phase 2, a message that keeps asking you to bring the card to the START button points to a worn battery or a card that has lost synchronisation. If the card is out of sync, open the car with the built-in key, then place the card on the card reader area.

Does the message stay on despite a new, correctly fitted battery and the four presses? Book a Renault workshop for a diagnosis, and do the same if the case is broken. Bring the vehicle with all its keys and cards: a Renault dealer initialises them all together when one is replaced.

Frequently asked questions

What battery does a Renault key take?

Use the code engraved on the old battery or printed in the cover: Renault names no type in its handbooks. According to a reseller and members of the Renault community, the cards of the Clio 5, Captur and Megane 4 often use a CR2032, which you should check on your own battery.

How long does a Renault key card battery last?

About two years, according to the Renault handbooks from the Clio 3 phase 2 to the Master 4. The “Key card battery low” message warns you before it fails completely. If you have to stand close to the car to open it, the battery is also near the end of its life.

How do I start a Renault when the key card battery is flat?

Depending on the message shown, place the card on the card reader area or hold it near the START button, then press START. On the Clio 4, insert the card in the reader. The emergency key inside the card opens the driver’s door.

Do I need to reprogramme the key after a battery change?

No, the Renault handbooks describe no reprogramming for a battery change. On a card, four presses of a button near the vehicle clear the “Key card battery low” message. Initialisation by a Renault dealer applies when the key itself is replaced.