Try to avoid washing your engine bay as much as possible. Before washing the engine bay make sure you disconnect the battery and do it. This 5 min of work will save you from major problems. Also dont spray water near the ECU. Do not vertically spray water near sensors. Sensors do have waterproofing to some extent, but still spray them sideways. Best way is to clean it with pressurised air. Most of the dust is removed with this.