Q: What would keep a service engine soon light on? 2001 BMW 330

Hi - quite often, a Service Engine Soon (SES) light is programmed by the manufacturer to alert you to possible service needs at a given mileage. At your mileage, checking the oxygen sensors and catalytic converter might be appropriate. Check for actual problem codes first - whether the Check Engine light is on or not. Most auto parts stores will do this for you for free. If there are no problem codes set, and the vehicle is operating properly, I wouldn’t worry about, and proceed to your next scheduled service. Obviously, if problem code are checked, have your car checked for needed repair. I recommend a Check Engine inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.