I have a 2006 LS430. The battery in the smart key fob generally lasted for 2 years or more until 6 weeks ago. When I replaced the battery, the fob worked fine, but only for about 3 weeks. I replaced it again, and again only 2-3 weeks of life. I can't believe both replacement batteries -- which were from different packages with different distant expiration dates -- were both defective. Is there a short in the key fob that is now draining its battery? Has anyone experienced this before? And what might be a fix? Thanks.

 

Buy a good brand battery then try again. If it still drains in 3 weeks, you'll know for sure there is a short in it probably caused by you when you replaced the battery. Did you employed good ESD practices when replacing the battery?