loop loo
daf units with a trailer is connected the ABS truck light will be on until there is a minimum of 4.5 bar pressure in the trailer air tank, it should say trailer ABS fault but for some reason daf decided this particular fault signal from the trailer puts the truck light on,
once the air pressur is up the light should go out, if i doesnt then drive the vehicle above 10 mph and see if it goes out, if its still on then you have an active fault in the system and i would need to know what the ecu part number is so i can let you know how to blink code the system.