These instructions apply to the Land Rover Defender Mk2 (L663) 2020-Present. For other models, please choose your vehicle here.
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The Land Rover Defender (L663, 2020–Present) is a fully keyless vehicle: the smart key talks to the car over a short-range radio link, and a flat coin cell inside the fob breaks that link. When the START/STOP button reports “Smart Key Not Found” or the doors stop unlocking on approach, the fob battery is almost always to blame — and the new Defender has a built-in backup so you can still get in and drive.
Start the Engine With a Dead Fob Battery
The Defender reads the key’s transponder chip by induction the moment you hold the fob right at the ignition — no battery required for that handshake.
- Sit in the driver’s seat and close the door.
- The message centre prompts “Position As Shown And Press Start Button”, picturing the fob against the START/STOP button.
- Hold the smart key flat against the START/STOP button as shown.
- Press and hold the brake pedal.
- With the fob still in place, press the START/STOP button. The engine starts and you can drive away normally.
Unlock the Door With the Hidden Emergency Key
If the door won’t unlock electronically, use the steel emergency blade inside the smart key.
- Press and hold the release catch on the side of the fob, then slide out the emergency key blade.
- The driver’s door lock cylinder is concealed under a small cap at the rear of the handle.
- Insert the blade into the slot at the base of the cap and gently lever it off to reveal the keyhole.
- Insert the blade and turn to unlock the door.
- Refit the cap once you’re inside.
Expect the Alarm
Opening the door with the blade can trigger the alarm, because the car hasn’t received a valid radio handshake. Get in and complete the dead-fob start — starting the engine with the recognised transponder disarms the immobiliser and silences the siren.
Replace the CR2032 Coin Cell
The L663 smart key runs on one CR2032 3-volt lithium coin cell. Slide out the emergency blade, then use the blade slot to split the fob halves. Fit a fresh CR2032 with the + side oriented the same way as the original and snap the case shut. Full keyless and approach-unlock operation returns at once.
Frequently Asked Questions
Where do I hold the key to start a Defender L663? Flat against the START/STOP button, exactly as the dashboard image shows.
Where is the emergency keyhole? Under a removable cap at the rear of the driver’s door handle — pry the cap off with the blade.
Does the Defender have a key-card or phone key I can use instead? Some L663s support Activity Key wristbands or a phone-as-key, but a flat fob still starts the car by the button-hold method above; the physical blade always works for entry.
The alarm went off when I used the blade — normal? Yes. Mechanical entry bypasses the radio handshake. Starting the engine clears it.
How long does the fob battery last? Two to three years typically. Replace the CR2032 as soon as keyless range starts dropping.
If a warning lamp stayed on after the flat-battery episode, decode the stored fault code at autodtcs.com.
Disclaimer: The information on this page is provided for general guidance only. Always follow your official service manual and safety precautions when working on your vehicle. We are not responsible for errors, omissions, or any damage resulting from the use of this information.
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