HI,
Could someone provide me with the battery model/brand number inside the remote key? I took mine out to get a replacement but I lost it.

 

I just tried to do the same: removed the screw which is close to the key shaft, but the plastic enclosure would not split open - it seems to be held together by something on the other side of the key head (where the elongated key ring hole is). I did not want to force it, being afraid to crack it.

Did you have any problem like this opening up your key? If you let me know and if I manage to take mine apart I'd sure tell you what the battery part ID is

 

Actually I just browsed the forum a bit more and found out that what I suspected was true - needed just to try harder sliding the key cover to get it open.

the battery in my gs430 key is Panasonic CR1616.

 

Thanks, but My car is LS400, I don't think it is the same battery!!

 

Found it under
http://www.lexus-parts.com/partlist....=22&ModelID=60

CR1216 - Remote Lithium Battery

 

CR 1216 is the correct battery for your model LS. The price at Sewell is $1.00, but you have to pay shipping charges. This battery is available at Radio Shack for about $3.00.

 

That battery is the correct one. You can also get them at your local WalMart at the jewelry section. It is a watch battery.