What happens to the indicator lights during engine start-up?

During engine start-up, the 'Check Engine' and 'Stop Engine' lights illuminate as the onboard computer performs a self-diagnostic check of the vehicle's systems. This process ensures that all critical functions are operating correctly before the engine runs. The activation of these lights is a standard part of vehicle diagnostics, signaling to the driver that the system is assessing the functionality of various components.

While it is a common misconception that all lights might remain off until the engine starts, this is not the case, as the diagnostic indicators must light up to confirm their operational status. The self-check procedure is essential for identifying any immediate issues that need addressing before the vehicle is used in emergency situations, ensuring safety and reliability.

Indicator lights flashing in sequence may be used in different contexts, such as during a specific mode of operation or alert. However, during the initial start-up phase, the lights serve the crucial role of providing real-time feedback about engine readiness and diagnosing potential problems.