These instructions apply to the Renault Kadjar Mk1 (XFE) 2015-2022.
For other models, please choose your vehicle here.
Renault Kadjar (2015–2022) uses Renault’s hands-free keycard with push-button start, so a flat keycard battery does not leave you stranded. The card’s immobiliser chip is passive and needs no battery, which means the engine will still start once you present the card to the reader by hand. The Kadjar has no dashboard card slot, so the method is to hold the card against the START button rather than dropping it in.
The first sign is normally the “Keycard battery low” message in the instrument panel. It often appears well before the card stops working, so use it as a prompt to fit a fresh cell.
Starting the Kadjar with a dead keycard
- Enter the car using the emergency key (see below) if the remote will not unlock the doors.
- Sit in the driver’s seat with the keycard in hand.
- Press the brake pedal fully and hold it.
- Hold the keycard flat against the START/STOP button. On some Kadjar trims there is a marked card reader zone near the centre console; if so, hold the card there.
- Press the START button. The car’s antenna powers the card chip and the engine starts.
- Keep the engine running until a new battery is fitted, as a dead card may not be detected for a restart.
Unlocking the door with the emergency key
- Press the catch on the keycard and slide out the integrated metal key blade.
- Find the lock barrel on the front door handle, hidden under a small cap.
- Remove the cap to expose the lock.
- Insert the blade and turn to unlock. The alarm may sound and stops once you start the car with the card.
- Return the blade into the card body before driving.
How the card reader and transponder work
The keycard combines a battery-powered radio, used for the remote lock and unlock buttons, with a separate transponder chip that runs without any battery. When you hold the card on the START button or the marked reader zone, the car’s antenna field powers the chip just long enough to read its security code. That is why a completely dead card still starts the Kadjar yet can no longer lock or unlock it remotely.
Replacing the keycard battery
The Kadjar card uses a single CR2032 3V coin cell.
- Pull out the emergency key blade to release the card cover.
- Unclip the back cover at the tab to reach the battery.
- Remove the old CR2032 and fit the new one with the polarity shown on the cover.
- Refit the cover and reinsert the blade.
- Stand beside the car and press a card button four times to re-sync. The warning clears at the next start.
Frequently Asked Questions
Where do I hold the card on a Kadjar? Against the START/STOP button, or on the marked card reader zone near the centre console if your trim has one, with your foot on the brake.
Can the emergency key start the engine? No. The blade only unlocks the door; the card must be at the reader for the engine to start.
What battery does the Kadjar keycard use? A CR2032 3V lithium coin cell.
Why does the card work intermittently before it dies? A fading cell transmits weakly. Once the low-battery message appears, fit a new CR2032.
Do I need to do anything after fitting a new battery? Yes. Press a card button four times next to the car so it re-syncs; the warning clears at the next start.
If a dashboard warning or stored fault code appears after the keycard goes flat, you can decode it on autodtcs.com.
Independent guide — not affiliated with Renault. Always follow your official service manual and safety precautions. Read our full disclaimer.