the oil level indicatior starts lighting up after you shut off the engine when you are half a quart low. Im sure its not exact but its been pretty accurate in my car if I check the oil level as soon as I see the light after I shut off the engine.
When it lights up when the engine is running you are a full quart low.
2005 BMW 330i ZHP 6MT. Built 11-19-04. Bought 4-2012.
Stock: Nav, leather, PDC, Xenon
Added by me: OEM Alarm, OEM heated seats, OEM aux kit, OEM Bluetooth, intravee, M3 strut brace, BMW Performance Intake, Nappa leather arm rest, updated LCM (triple blink, euro hazards, trifecta lighting, 3 stage brakes), temp gauge