These instructions apply to the Toyota C-HR Mk2 (X2/XH2) 2023-Present. For other models, please choose your vehicle here.
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A weak smart key is the usual reason a Toyota C-HR Mk2 (2023–present) stops locking from a distance or shows a “key battery low” message. The fob takes one coin cell and you can change it in a couple of minutes.
Battery You Need
The C-HR Mk2 smart key uses a CR2450 3 V coin cell — the larger Toyota smart-key cell (not the smaller CR2032). Check it before you buy.
How to Replace the Key Battery
- Slide the lock catch and pull out the mechanical key.
- Insert a small screwdriver into the slot (tape the tip to avoid marks) and split the key cover.
- Lift out the old CR2450, noting the orientation.
- Fit the new cell with the positive (+) side facing up.
- Clip the cover back together and slide the mechanical key home.
Lock and unlock from a few metres to confirm.
If It Still Won’t Work
- Start the car anyway — touch the smart key to the start button as you press it; the car reads the transponder directly.
- Lock/unlock manually with the mechanical key (the driver’s door lock is behind a small cap).
Note: programming a brand-new key requires Toyota diagnostic equipment, but a battery change never does.
Frequently Asked Questions
What battery does the Toyota C-HR key take?
A single CR2450 3 V coin cell, positive side up.
Do I need to reprogram the key after changing the battery?
No — only adding a new key needs dealer programming.
How do I open the C-HR smart key?
Slide the catch, pull out the metal key, then prise the cover apart with a taped screwdriver.
My key still won’t start the car — what now?
Hold the key against the start button as you press it.
For a no-start with a warning light, check the code on autodtcs.com. See also our C-HR battery guide if the car is dead.
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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