Key battery low

[Carl H]

Apologies if this has already been asked (the search box doesn't show up anything relevant), but....

My 2009 Avensis has just told me that the key Battery is low. 

What kind of Battery is it?

How do I change it? There's no obvious way of taking the key fob apart. 

It's the keyless type. 

[Konrad C]

I assume you did not get the handbook, which covers Battery replacement on pages 470-472. The Battery you need are CR2016 Battery for the standard key without smart entry and start system, CR1632 battery for car with smart entry and start system.

For the standard key, remove from the key ring, use flat bladed screwdriver. Remove the module and again use screw driver to remove the cover. Using a very small Philips screwdriver or similar, exchange battery remembering the + side with the writing facing up. The put everything back in reverse. 

For smart entry and start system, remove the manual key, then remove cover with screwdriver. Exchange battery.

For later standard keys, after removing the cover, just exchange the battery.