I am new to the site, and also new to Lexus ownership. This has been a battle from day one. We purchased the car from a friend of a friend. The car is beautiful, and ran like it was brand new. Until the car sat while they were on vacation for two weeks. The car was then a no start problem. The owner of the car had the computer rebuilt by ( I think it was called relentless), still a no start issue. They decided to sell, and we jumped on the chance to pick up such a nice car. The car was taken to our mechanic, and he found an issue with the MAF wiring. After this repair, car was running great again. My daughter went to pick up the car, and all it did was crank over. Scanner showed that there was a communication issue with the key. Brought another key from the house, and it started right up. My daughter drove the car 100 miles that day showing the car off to her friends. She tried starting the car two days later, and it has a no start issue again. Back to our mechanic again. If we unplug the immobilizer, the car will start up and run for a few seconds. Then shut off, it will do this all day long. When we plug the immobilizer in, the car will only crank over. Our Mechanic feels that this is what the issue is. I have brought the keys to a locksmith, and all of the keys are functioning properly. The car was put on his scanner, and he couldn't find any issues. The car actually started one time, and ran perfectly. We shut the car off, and a no start issue again. We have replaced the coil around the ignition key, changed the BCM under the drivers side dash, and the computer was rebuilt by a very well trusted company. I am not sure what steps we need to make next. I did find out that the 97' is the only style with the immobilizer separate from the ecu, and can be a nightmare.
I thank you all in advance for your assistance, because my daughter is devastated that she cannot drive her dream car. I am trying to get this solved, so she can enjoy this wonderful car again.



Thank you, Andrew

 

sorry to hear your troubles. what's the mileage?

when you insert the key into the ignition (but not turn it at all) the security light on the dash should stop blinking immediately if the key is coded properly. if it doesn't then the immobilizer is still active. you will need the dealer to reprogram the ECU/key as the immobilizer key is supposed to be coded into the ECU as not all locksmiths can do it.

 

Thank you for this information. I will look at this once I get home. Honestly, I am sure if the light works or not. I will update once I get home tonight.
Thank you, Andrew

 

Forgot to mention, mileage is just over 200,000.

 

That is a beautiful car! Frustrating if it can't be trusted to start I bet.

How does it act if BOTH keys are in the car? Do you have the valet key also?

 

It is unbelievably frustrating, but with the condition of this car we want to make sure it is repaired correctly. I know this will be a dependable car once we identify the issue. We do have both keys to the car, the valet key, and the credit card key for the door.

 

Just wanted to give an update on our LS400.
The security light does not work, and we are waiting for a replacement dimmer switch / security light combo. Hopefully, we can see what the security system is telling us. Thanks again, Andrew

 

Here’s one more update on our LS400.
out security led light was not turning on, so we bought a used dimmer combo switch out of a newer LS. We finally received the combo switch, and this led bulb is not coming on either. Does anyone know the color of wires the illuminate the led, and what voltage it would receive? I would just like to test the led bulb to see if this is the actual issue, or if we have an issue of no voltage coming to it. Which would open the door to other issues. Thank you again for any assistance available, Andrew

 

to verify the light is working, have you tried to arm the car from outside and see if the light illuminates?

 

we can lock the doors with the remote, but the security light still does not come on.

 

We have had our ls400 at the Lexus dealer for the last few days. Their comment was that the car is a “paperweight.” They said they do not have communication with the ecu, all fuses are good. They were going to try replacing the ecu, the new immobilizer and a couple of other items. They can not order any parts for the 97’, because it is all discontinued. So here we are, a beautiful car and it’s officially a “paperweight “ now. Not sure what the next steps should be to solve this. I am on the look out for some used parts. I have a replacement immobilizer, but it is not programmed to the keys we have. I was reading about a company in Washington that can reprogram this, but I can’t find that old thread.
Any suggestions as to what the next step should be? From what I understand, the 97’ cannot have the immobilizer bypassed. It is a separate ecu / immobilizer. Is this still true?
thank you all again! One day we will have this thing running again!

 

Give this a watch. Kelvin is very knowledgeable and incredibly helpful


I would suggest reaching out to him to discuss possible solutions. While it may not be cheap, he is very good at what he does.

As mentioned in the video, it is possible to run a 95-96 ECU in your car IF you repin the connectors, as some of the wires were changed like the igniters to prevent disabling the immobilizer easily. However, it's not necessarily the ideal solution.

 

Thank you for the lead on this shop!
I will definitely reach out to him!
thanks again, andrew

 

Thank you again for the lead to CarTunes!
I have spoken to him a couple of times, and our ECU was shipped to him last week. We had to get the car back from our local Lexus dealer. While they were unable to source new parts for our car, they didn’t charge us for the diagnostics. I did thank them for that.
I will keep everyone updated on the progress of the immobilization by-pass. Please keep you fingers crossed for us! Thanks again, Andrew

 

I want to thank you again for the lead on CarTunes!! We received the ecu back from New Zealand yesterday.
After sending the car to a couple of mechanics, a trip to a lock smith and eventually the Lexus dealership. We were told the LS was a "paperweight.." The dealership could not order new parts, because everything is discontinued. We were given the lead to CarTunes, and after a couple of conversations, we shipped our ecu to them. Fast forward to yesterday. Installed the ecu, and the car fired right up!!! Turns out this WAS an immobilization issue the entire time!
Thanks to this site, we have our beauty back on the road. I can't recommend CarTunes, or Kelvin enough, they saved this car!
thanks again, Andrew