Why will your Lexus IS300 engine will not turn off?

If your Lexus IS300 engine won't turn off, it could be due to a faulty ignition switch, a malfunctioning relay, or a stuck key in the ignition. Additionally, issues with the vehicle's electrical system, such as a short circuit, could prevent the engine from shutting down. In some cases, problems with the engine control unit (ECU) may also cause this issue. It's best to consult a professional mechanic to diagnose and resolve the problem.