I have been working on this IS250C for 3years . I brought it from the auction and it did not come with a key. I replaced the key fob and module the immobilizer in the dash, the steering column module the radio with the nav. and I bought a brand new ECU from the dealer and I replaced the engine . The problem I am having is the dash lights up . The security light continues to flash and the vehicle will not start. I jumped the starter relay and I can hear the vehicle engage but will not start from the inside of the vehicle. I was told I need to program the immobilizer but here in Michigan we have no one with expertise to do so . If anyones knows a knowledgeable Lexus mechanic or can let me know what I can do to get this vehicle started. Please help.

 

Unfortunately there is nothing you can do to get the vehicle started at home.

Option 1 - Tow it to the dealer and with the use of the Techstream the dealer can get you up and running. That will cost whatever they charge.
Option 2 - Contact a local locksmith...reprogramming/programming Smart keys is within their scope of work...assuming they have the equipment and knowledge (another member used a locksmith who was in similar type situation)

All the modules you replaced, I hope they were damaged somehow, cause the immobiliser could have been reset by the dealer without replacing them (I'm pretty sure, but not 100% sure).

 

Thank you for the answer. I will visit the dealer tomorrow to see if they can program my vehicle.