These instructions apply to the Lexus NX Mk1 (Z1) 2014-2021. For other models, please choose your vehicle here.
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If the smart key on your Lexus NX (2014–2021) has lost its range, needs to be held close to the door handle, or shows a low-key-battery message, the coin cell inside is almost certainly flat. It’s a quick swap — just check which of the two key types you have, because they take different cells.
Battery First — Two Key Types
The NX came with two smart-key styles, and the cell differs:
- Standard smart key (with a pull-out mechanical key) — CR2032.
- Card-style smart key — CR2412 (a thicker, less common cell — check before buying).
If the key is dead, you can still start the car: hold the key against the START button as you press it. The mechanical blade hidden in the standard key unlocks the driver’s door.
Replacing the Cell
Standard smart key:
- Push and hold the release knob and pull out the mechanical key.
- Use a screwdriver to split the case at the seam.
- Lift out the old cell (don’t touch the terminals) and fit a new CR2032, positive side up.
- Close the case and refit the mechanical key.
Card key: slide off the cell cover, fit a new CR2412 positive side up, and refit the cover.
Lost Key or Adding a Spare
A cell swap keeps the existing coding. Programming a new key needs Lexus dealer equipment through the immobiliser — there’s no owner sequence.
If a Fresh Cell Doesn’t Help
- Check you fitted the right cell (CR2032 vs CR2412) the correct way up.
- Hold the key to the START button to drive in the meantime.
- Still flagging a fault? A smart-entry issue can store a code — look it up on autodtcs.com.
Frequently Asked Questions
What battery does the Lexus NX key use?
A CR2032 in the standard smart key, or a CR2412 in the card-style key — check yours.
Do I need to reprogram the key after the swap?
No — the coding is retained for a battery change.
Can I program a new NX key myself?
No — a new key must be coded by a Lexus dealer.
The key is dead — how do I start the car?
Hold the key against the START button as you press it; the car reads it directly.
If the key flagged low after a battery disconnection, see our NX battery disconnect/reconnect guide.
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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