cyfi66

I purchased a credit card key from Lexus and attempted to program it myself on my Techstream. When I touch the existing key to the ignition switch I get the beep from the car, but when I touch the new credit card key to the ignition switch nothing happens.

I checked the battery it came with and it was completely dead, so I replaced it with a new one and still nothing when I go through the programming sequence and get to the part where I touch the new key to the start button.

The new battery shows about 3.0v when checked with a DMM while installed in the key. It was purchased new from McMaster Carr.

Is there anything else I could do to troubleshoot? I did make sure to follow the Techstream key programming steps to the tee including moving the other key far from the vehicle during programming etc. Thanks for any help!

lobuxracer

iTrader: (2)

That happens when the key is not the right unit for your car, or it has already been programmed to a different ECM. That should not happen with a key purchased from Lexus when they have your VIN, but your results match what I have seen with an incorrect key.

cyfi66

I am thinking the battery is still suspect, sometimes I check it and the voltage is as low as 2.6V. I am going to request a replacement.

However that begs the question is the battery even needed for key programming? If the key is next to the start switch I thought that a dead key would still function.

This is the part that I ordered from Prestige Lexus (didn't provide my VIN). It appeared to be in the original packaging but I already threw it out so I can't say for sure if they sent me the correct part or not. Any idea on how I could verify what the problem is?

https://parts.prestigelexus.com/p/Le...990430L50.html

lobuxracer

iTrader: (2)

There's a big thread in the IS F forum about this. Different model years have different keys. I know this because I ordered one that works with some IS Fs, but it wasn't the right one, and I had to return it for the correct one. Symptoms were identical to your experience. I also got a key with a bad battery. It will program, but it won't work unless you hold it right up to the start switch. I figured it out pretty quickly, and I have a small stash of batteries for these keys since they have a super long shelf life and seem to die suddenly, so everything was fine with a new battery.