Lexus LX Engine Start Issue

I had a similar issue with my LX – not sure the year is relevant. It sounds like the anti-theft system is engaged. Does your remote start also seem to be malfunctioning? When the key is not correctly recognized by the ignition control system, there are a series of events that occur in a specific timing, and if the control units don't get the expected response, the engine is shut down.

Remote start is dead, yeah. So, ignition control problem for sure then? Is there anything to check or do myself, or does this sound like a dealer thing? Like a software reset or something?

Based on what you've described, and the fact that the remote start is also non-functional, it almost certainly points to an immobilizer fault stemming from incorrect key programming, similar to the orchestration where if one instrument is off, the whole performance falls apart. While some rudimentary diagnostics are possible, without specialized equipment to reprogram the transponder and access the ECU, the issue will persist. I'd recommend taking it to a qualified workshop to have the key reprogrammed to match the vehicle's anti-theft system.

Spot on! Workshop visit confirmed it – key reprogramming was the culprit. 45€ later and it's purring like new. Thanks for the steer!