I'm registered for my first HPDE school this summer (excited!) I have a 2002 530i (146k) and the DSC light won't go off. I rarely drive with DSC on, as I don't like the feel of the car with the "nanny" options on. I suspect I may need an ABS unit, but it'll be tough to shell out more $$$ after having paid for the school and related expenses (and FSU, starter, bushings, and sway bar for the car this past summer) I guess I have two questions: -Everything else on the car is drive-ready (school's checklist is all signed-off on); is it possible the instructor(s) won't care the DSC light is on? I certainly don't want to put myself or anyone else at risk, but the car has been driving great with the light on for months. -If I should just bite the bullet and get out the American Express for another garage bill, are there a few things I can do myself to check if there's just a disorder with the indicator light before I take it to my mechanic? (i.e., pull a fuse or two?) I know a lot about my car, but I'm def. not a DIYer on this complicated beast.
Pulling fuses would probably disable your ABS altogether. As someone who has lost ABS unexpectedly just before a turn [on track], it was an eye opening experience expecting the car to turn left yet it continued to go straight off track. I wasn't even hard on the brakes. While on track I always turned off traction control. I never found a need a need to disable it on the street. Me? I'd fix it.
You can check if the ABS is working easily enough, brake hard and see if you lock up the brakes (ie, tires skid). Normal ABS function cycles the pressure to the brakes to keep the tires from locking up - you'll feel the brake pedal pulsate under hard braking, and possibly hear a little bit of intermittent tire chirping (if the roads are dry) as the abs cycles (rrt-rrt-rrt-rrt-rrt). More easily done on wet roads, but the tire noise would be more like chh-chh-chh-chh. Obviously you would want to do that on a straight, level road with no-one in front or behind. If the ABS is not working, the brakes will lock-up the front wheels if you brake hard enough (they'll stop turning), and at that point, the tires are just skidding (skchhhhhhhhhhh), and the brake pedal won't pulsate. You don't want to skid the tires for any length of time, you'll flatspot your tires. Also note that for as long as the front tires are locked up, you have no directional control, if you kept them locked up, you can crank the wheel one way or another and the car will continue in the direction you were going when the brakes locked. However, release the brake pressure and allow the wheels to start turning while you have the steering wheel turned, and the car will turn - abruptly, and possibly with the risk of throwing the car into a skid or spinout. So - don't do that - keep the steering wheel straight for any brake-checking... much safer. If you unplug one of the ABS sensors and a light different from the DSC light comes on, that would show it has different warning lights for the ABS system & DSC. If your ABS is working, my take would be the DSC is less critical - but others might feel differently - perhaps that question is best directed to your driving school's chief instructor or school organizer. There are two sides to that - running without DSC, you're not relying on electronic supports for your driving (potentially you learn more), but, if you make a mistake and get in over your head and the electronics spare you some sort of mishap, that ain't all bad either. Usually, in a first weekend out, you're trying to learn & process so much in such a short period of time, worrying about DSC on/off is going to fall towards the bottom of the priority list. I think some schools would have you run with it on unless it were non-functioning.
