STEDI H4 Canbus Cancellation Module (Pair)H4 CANBUS Module to bypass vehicle computer systems that deactivate headlights due to higher or lower current draw. DESCRIPTION SAY GOODBYE TO DASH WARNING LIGHTS. Our H4 Canbus Error Cancellation Module will prevent dash warning lights when upgrading to LED or HID. These can also be used to resolve the polarity issue when upgrade headlamps on negatively switched vehicles. THE NITTY GRITTY. Our H4 Canbus Error Cancellation Module will prevent dash