How to Reprogram a Lexus Key Fob

Reprogram a Lexus Key FobIt’s easy to overlook, but one of the most advanced pieces of technology in your Lexus is the key fob. Computer technology has led to fobs that help prevent theft while adding convenience to your driving experience. These days, the key rarely needs to leave your pocket or purse. But when this advanced driving tool runs into problems, it can be surprising and frustrating. In fact, one of the most common issues with key fobs is the need for reprogramming. This can happen when the fob’s battery dies or if you get a replacement fob. In either case, there are steps you can take to get the key reprogrammed and working normally.

Replacing a Battery

Perhaps the most common reason to reprogram a key fob is that the battery died. When you replace a battery, the fob will forget its previous programming, and sadly, it won’t still work with the vehicle. The good news is that there is a trick of sorts to reconnect the fob. Before trying this, it’s important to understand that this method will only work with a fob that has previously been connected to the vehicle. If you have a new fob, skip to the next section.

Assuming you have already replaced the battery in the fob, your first step should be to reset the vehicle’s computer. You can do this by disconnecting the battery for at least 30 seconds. Once done, reconnect the battery.

Next, put your key in the ignition, and turn it to ON.

Then, turn the key to OFF.

Turn it to ON again, and then try to lock the door with your hand while pressing the lock button on the remote. Then, turn the ignition to OFF again.

Now remove the key from the ignition. Put it in the driver's door, and unlock and lock the door with the key and the buttons at the same time. Repeat this process for a total of three lock/unlock cycles.

Remove the key from the door and shut the door. Try to unlock the doors with the remote. If that works, open the door and start the car. If it starts, then you were successful! If it doesn’t work, you may have to repeat the process, starting with the key in the ON position. (You don’t have to repeatedly reset the vehicle’s computer). In some cases, you may have to go through the process a few times before you get a successful connection.

Programming a New Key

If you are replacing a key or getting a new spare, then you can’t use the lock/unlock method. Instead, the new fob will have to be programmed via software. Let’s pause before getting into this. Programming a new key fob requires some specialized equipment. In particular, you need an OBD2-to-USB cable, and it has to support VIM communication protocol. You also need a working key remote. Without all of these tools, the method won’t work. The good news is that you can always take the new key to a certified mechanic. They’ll have the tools, and although you’ll be charged for a service, you can count on it working.

But if you’re ready to do this yourself, this is how you program a new fob.

You’re going to start by installing the Toyota TIS Techstream software on your computer. Technically, you can use any Windows computer, but this will be much easier with a laptop computer. Ultimately, there will be a cable running directly from the car to the computer.

Since your software is installed and running, you’re going to use your OBD2 cable to connect the car to the laptop. In order to get the two communicating, you’re going to press the Engine Start button two times without putting your foot on the gas. This will turn the car computer on without actually starting the engine.

In your TechSTream software, you should get an opportunity to connect to your vehicle. The program will automatically detect your car, and you can use the displayed information to confirm that you, in fact, have a good connection.

Now you have the main menu on the screen. You want to use it to get to Smart Access. From there, you will select Utility and then Smart Code Registration.

Follow the onscreen instructions. They will walk you through the procedure of registering the new fob. You’ll go through a series of steps that involves both keys, and once complete, the new fob should be registered and functioning. If you have more than one key to register, you will have to do them one at a time.

Visit Krause’s Automotive

We certainly understand trying to save money and go with the DIY approach. If you run into any trouble, or if you want to save yourself some hassle, professional key programming is among the services offered at Krause. We're the friendliest, most professional auto shop in Lewisville, and we’ll be happy to take care of your Lexus any time. You can call us today or fill out our online form. We’ll answer your questions and we can schedule your service to make sure you have full access to a working, reliable vehicle.