My LS came with the two original Smart key fobs. I have replaced both batteries. Most of the time when I am in the car alone, I can unlock (via the door handle) and start the car with the key in my pocket.
Many times, when my wife is with me and has her fob in her purse, I can unlock with the handle but can't start the car. It stops before the first position. Sometimes it will only start if I insert the fob in the dash. What gives?

 

What happens when the wife's key is used and your key is not in proximity? Does it still work completely as it is supposed to.

Also, are you saying that your key is not 100% operative when used alone without the wife's key in proximity?

 

Most of the time, either key, by itself, will work. Maybe once out of fifty times, I will have to exit the car, relock, then start over and all will work.

 

I'm just thinking that the keys may not be a "matched" pair, with one being a replacement key with a different frequency. You dealer might be able to clarify the problem and a possible remedy.