ECU faults can be categorised based on the systems they impact. Common categories include Engine Management, Transmission Control, ABS, Airbag Control, Fuel Injection, ESC, Climate Control, Throttle Control, Immobiliser, and EGR System faults. Symptoms vary, from warning lights to performance issues. Solutions involve diagnostic testing, sensor or module replacements, and system checks, often requiring skilled technicians and specialised tools for effective resolution.