Quick TakeawayThe most useful times to book a car computer scan, from warning lights to rough performance.
Use scanning before a small fault grows
Book a diagnostic scan when the check-engine light appears, the car loses power, fuel consumption changes, or the engine runs unevenly. Intermittent symptoms are also worth recording and checking.
If a warning light is flashing or the car is overheating, stop driving and seek professional help. A scan is part of the diagnosis, not a substitute for safety inspection.