I have a bmw 5 series 520d n47 engine every now and then it emits clouds of blue smoke for 30 seconds or so it can be days or weeks apart this time it was 20 days.

SOURCE: BMW 5 series - 2005 model - resetting service & waring lights

the brake pad warning light is controlled by a sensor located in the front and rear brake pads, small contact with 2 wires that plud into a harness, if they are bad I think the replacement cost is around 5-10 dollars for a new one, there will only be one in the front and one in the rear, the service light is turned out by a special tool at the dealer

SOURCE: Hi I have 2000 BMW 320i. Lumpy idle when cold and oil light for

Your oil is a little low, and the timing may be off a bit but if it smooths out after warm it is probably ljust
low oil.

SOURCE: bmw x5 3.td blue smoking coming out engine

RINGS AROUN THE PISTON, OIL LEAKING INTO THE COMBUSTION CHAMBER

SOURCE: 2001 BMW 325i problem: Car runs very rough, but no warning lights

Sounds like a fuel problem , have you changed the fuel filter in a while ? could be the knock sensor or the knock sensor module needs to be replaced.

SOURCE: BMW X3 2.5si M series. High Oil Consumption

hi, this consumption seems high, i would take it to a dealer and ask them to check the oil sensor.......
P.S. is there a lot of smoke coming from the exhaust, if so, it may be burning a little oil, ask dealer to check it