I have a 2006 IS 250 AWD and the distance on the remote is getting worse on a daily basis. It seems like a battery is going bad, but I have 2 separate remotes and both have new batteries, so it's NOT the key fob. It seems like there is a similar battery in the car receiver that is going dead.
My guess is that I need to replace the receiver in the car. What can I check/replace besides the key fob?
Thanks!

 

When is the last time your car's battery was replaced? If it's been some years or not, got to you local autozone/advance/chief and get your charging system and battery tested. I've not had this problem on my IS, but I do have a Ridgeline and I noticed once when the same thing started happening, my battery in the truck was getting weak. I replaced the battery and BAM!, distance on my key fob came back.

 

If the voltage is dropping, that could cause range to drop, yet still be enough to start the car without any problems.
It's 3 years into a 7 year battery, so my guess is that it's good though.
But it certainly is possible, so I'll get it checked tonight...

 

There are several things that can cause a weak battery as you probably know. Your car is 10+ years old so the alternator or voltage regulator could be pooping out on you. That's why I suggested a full charging system check.

 

System checks out, everything is operating 100%.
I'm not sure, but I'd imagine even if I found a decent priced receiver replacement, I'd still need the dealer to program it into the system.

 

Let the dealer diagnose the problem before you go buying parts.