May be merc bought up he remains of DAFs old pad looms …Pads look fine the one in the pic wouldn’t put a warning on …A simple check is wind all the calipers back ,(workshop environment ,wheels chocked etc ) if the light is still on after you cycle the ignition then it is a wiring / caliper issue…Generally I find it’s the steer axle to fail as it flexies the loom with the wheels turning left and right