Modern vehicles are packed with electronics. From engine control units (ECUs) and battery management systems to sensors, cameras, actuators, and power electronics, today’s vehicles rely on hundreds of electronic components to operate safely and efficiently. While these systems are designed to perform flawlessly, they must also survive one of the harshest environments imaginable — the real world.

Imagine driving on a winter morning. The engine has been running for over an hour, and components under the hood have reached operating temperatures of 100°C or more. Suddenly, the vehicle passes through an icy puddle or slush-covered road. Within seconds, extremely cold water strikes components that were just moments ago operating at high temperatures. This sudden change in temperature creates a phenomenon known as thermal shock — and the ISO 16750-4 Splash Water Test is designed to validate whether automotive electronics can survive it.