heron

From your explanation, it really looks like something wrong with some electronics in the car engine management system. If any problem with one component happen like with engine, fuel or other, then other still works like lights, radio etc. This situation seems like typical stolen car scenario when car completely shuts off everything down when it think that car has been stolen. You can unplug your battery terminal for 30 minutes and restart car with original key. If it still fails, ask your mechanic to find out the wiring of Immobilizer and diagnose them with proper chart or diagram from Lexus service manual (available online for couple of dollars) if any wiring has been short circuit? If for test they can bypass and disable the immobilizer and start the car you can zero down the root. Hope it helps.

Hi girijai, have you figured out any way yet? Appreciate to hear any positive development on the subject. Thanks in advance.

Please find pictures below, that tells the difference.

warning sign has stopped working the other lights are working fine. How to fix this?