ClubLexus - Lexus Forum Discussion

Lexus IS: Why is My Key Fob Not Working?

Figure out what's gone wrong with these tips. Learn how to replace the battery, reprogram it and more!

By Cynthia Griffith - December 11, 2014
Contributors: Peter Finn, Lexus Champion, stktrdr2

This article applies to the Lexus IS, GS, ES, and RX (2005-2014).

A Lexus key fob that suddenly stops working is never a welcomed surprise. Should you replace it? Is the battery dead? Before you curse the day, here are a few steps that will help you determine your next course of action.

Step 1 - Change the battery

It might be that your key fob is functioning perfectly and the problem is the battery inside of it. The key fob is fairly easy to take apart. These listed steps will aid you in the battery replacement process:

  • Press the small latch on the bottom of your key fob and remove the rectangular hardware by pulling down and out.
  • There is a tiny hole located just left of the center of the key fob. Insert the end of the rectangular hardware into that hole and snap the key fob open.
  • Once the fob is open, remove the small motherboard with a flathead screwdriver.
  • Carefully flip the motherboard over being certain not to touch the tiny micro chips. On the other side of the motherboard you will find the battery.
  • Remove the battery and replace it with a new one. Be certain that the plus sign on the new battery is facing up.
  • Return the motherboard to its original position in the key fob.
  • Snap the cover of the key fob back into place.
  • Re-install the rectangular piece at the bottom of the key fob.

Featured Video: How to Change Smart Key Battery

Step 2 - Reprogram the key fob

Even if your battery is intact and your key fob is technically unharmed, there is a possibility that it needs to be reprogrammed. Unfortunately, there's no way to do this at home. Dealerships have been known to charge between $40 to $160 for a reprogramming. Be sure to ask around at different dealerships and mechanics before shelling out for a reprogrammed key fob.

(Related Discussion: The Truth About Reprogramming Lexus Smart Keys - ClubLexus.com)

Figure 1. A set of reprogrammed Lexus key fobs.

Pro Tip

Purchase a spare key on eBay and have the locksmith cut an extra so you can avoid this annoyance in the future.

Step 3 - Bargain hunt for a new key fob

You might find a cheaper key on eBay that will come in handy, especially if your key fob has been misplaced.

If you can't find your key or you don't wish to endure the hassle of hiring a locksmith who knows how to reset Lexus ECU's, you might still be able to save yourself some time, money, and aggravation by making use of sites like eBay and Craigslist. Select dealerships will program your newly purchased key fob free of charge.

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