AndyC_67 Posted January 19, 2016 Report Share Posted January 19, 2016 Apologies as the answer is probably here somewhere but all the posts I have read (here and online) are never quite the exact same fault. Car is 330ci convertible 2004. I get the dsc and handbrake light coming on with a "beep " after about 20 m of driving. All posts I have read mention these 2 lights plus the abs. My abs light does not come on and abs works fine. It's only ever just these 2 lights. It has been like this for a couple of months (will fix when weather gets better) but oddly over Christmas the lights went out and stayed out as they should for a couple of weeks. I have been told it may be worth renewing brake fluid. So I guess my first question is.. When bleeding a system with dsc does engine need to be running? Second question is...if it's one of the dsc pressure sensors is there any way to find out which one is faulty? Sorry for the long post! Thanks Quote Link to comment Share on other sites More sharing options...
quicky330 Posted January 19, 2016 Report Share Posted January 19, 2016 Have u read the fault codes yet. Its the only way to see what the problem is. The lights could mean quite a few things so get them read and let us no what they were. Sent from my LG-D802 using Tapatalk Quote Link to comment Share on other sites More sharing options...
AndyC_67 Posted January 19, 2016 Author Report Share Posted January 19, 2016 Thanks I will get it sorted and let you know. I did get it "read" at a local bmw specialist place but he just said it's you dsc pressure sensor. I didn't see the code and he didn't say which sensor is was (of the 2 on the unit). I was unsure why it would suddenly work fine for a couple of weeks though. That's why I was thinking of fluid change. I have seen scanners on eBay (C110 & C310) have been the ones that seem like they may read these codes.Have you or anyone out there tried one? They are under 50quid so I was thinking of getting one. Any thoughts?? Thanks Quote Link to comment Share on other sites More sharing options...
doog79 Posted January 20, 2016 Report Share Posted January 20, 2016 Sounds like the dsc pressure sensor. Had to do one on mine when I bought it. A mate with a code reader told me what one it was. It was changed and brake fluid changed at same time. Can't rember of the top of my head but I'm sure break fluid needs done every couple of years on the e46. Mine was quite intermittent at first then eventually started coming on all the time. Ended up getting mine from the stealers as a 2nd hand one I bought of the bay was also faulty. Never had the dreaded beep and lights come on since. My heart still skips a beat when I here the beep for less than 3C outside thinking it's going to be the other sensor lol Quote Link to comment Share on other sites More sharing options...
Dave330 Posted January 20, 2016 Report Share Posted January 20, 2016 14 hours ago, AndyC_67 said: I was unsure why it would suddenly work fine for a couple of weeks though. That's what dodgy sensors can sometimes do - intermittent working, or intermittently working within parameters. Once they go outside of parameters, they throw a light/code/wobbly. How much are the pressure sensors? Is it significantly more difficult to replace both than one? Quote Link to comment Share on other sites More sharing options...
AndyC_67 Posted January 20, 2016 Author Report Share Posted January 20, 2016 Thanks. About 100 quid each I think and it's probably easier to do both at once. Have you tried one of the fault scanners (see above)? Quote Link to comment Share on other sites More sharing options...
Tim-Ci Posted January 24, 2016 Report Share Posted January 24, 2016 Mine put the DSC light on about a month after I bought it, and one or two others (can't remember which). It had a fault code for a DSC pressure sensor. The lgihts were was coming and going intermittently. One day when trying to troubleshoot the problem with a diagnostic scanner showing the live data from the pressure sensors, I pushed the pedal as hard as I could with the engine running, it been fine ever since (about 7 months). I did a brake fluid change soon after. I think my sensor had got jammed slightly or gummed up, and by pushing the pedal extremely hard with the engine running, this freed it off, and the brake fluid change was extra insurance to try and clear any debris out. I'm guessing the sensor is mechanical and relies on a spring loaded part to deflect as the pressure changes in the system, allowing an electrical reading to be taken for the ECU. Quote Link to comment Share on other sites More sharing options...
AndyC_67 Posted January 25, 2016 Author Report Share Posted January 25, 2016 That's interesting as someone else I spoke to about it said there is a chance that there could be some kind of "blockage" and suggested a fluid change as a cheaper first option to try. That said is there any special methods of bleeding the system when it has dsc or can it be done the "normal" way ie caliper furthest away from master cylinder first etc. Quote Link to comment Share on other sites More sharing options...
Tim-Ci Posted January 25, 2016 Report Share Posted January 25, 2016 I think the bleeding is the normal order. Be careful to avoid running the master cylinder dry, as if you do you then have to use diagnostics to activate the ABS pump to purge it out. So be careful not to drain all the fluid from the reservoir and suck air in. Also the BMW recommended fluid is not normal DOT4, it's DOT4 LV (LV stands for low viscosity). This is more runny than normal DOT 4 fluid, and helps the DSC system to work quickly enough in very cold temperature when the fluid thickens up. I think I got my DOT 4 LV from Opie Oils from memory, price was okay but still expensive compared to normal DOT4. 2 litres should be plenty to do a good flush and make sure all the old fluid is flushed through. Quote Link to comment Share on other sites More sharing options...
