I just purchased a 2001 LS430 about a week ago. While driving the car home, noticed that the security light blinks the whole time the key is in the ignition. It sort of has slow heart be blinking pattern - blink blink…….blink bink……blink blink and so on.
Anytime the key is out of the ignition and the doors are locked, the light is on solid.
Possibly related - The owner purchased the care about 2 years ago from a used car dealer and only received a valet key. He had a new master key made and programmed at the local lexus dealer (gave me that receipts). He said that about one in 100 starts, new master key doesn’t work and he is forced to use the valet key. I’ve called the service department at my local lexus dealer and they affirm that a blinking security light indicates there is an issue and that the only thing they can do is try and track it down for 130/hour. If anyone has any idea what this issue may be, or has an idea on how I can track it down, please post a response.

 

The light is trying to tell you that you mad a very poor choice by failing to have the entire car inspected prior to purchase. This is most likely only the tip of the electronic iceberg of problems with this car. You should have allowed the previous owner to correct the problem on his dime before you paid a cent for the car.

 

I didn't google enough before posting
here was the answer:
http://us.lexusownersclub.com/forums...howtopic=63124
"The car was in the key registration mode and it was returned to normal mode by turning the key on & off 5 times within 10 seconds"

it worked like a charm!

 

Glad you solved your problem, thank goodness for google.