CAN Bus means Controller Area Network Bus. This system monitors your vehicle and reports operating conditions. Some vehicles with complex internal computers(such as Audi, BMW, etc.) might report on-dash errors or flickering on the headlight or fog light. The warning canceller fixes the dashboard warning and flickering problem.
Bulb Out Dashboard Error: On some vehicles, the dashboard will report as if you have a headlight bulb missing or burnt. It does not affect the headlights functioning, but the light on-dash will be on. The warning canceller fixes the issue.
Flickering Issue: This happens when your vehicle does not recognize the new headlights installed. When turning the headlights on, the vehicle's computer does not understand the signal back from the headlights hence thinking they are still off. This triggers the headlight flickering effect. The warning canceller solves this issue.