Installed canbus ready LEDs in my reg plate & was advised I can put them in my sidelights but since doing so it has caused the warning light for external lights to show.
Canbus will expect to see the resistance/load of normal filament bulbs. LEDs pull much less current so faults are raised. You might be able to reset the bulb fault trip point with multiecuscan, but more likely it needs ballasted LEDs to keep the canbus happy.