Over the last 6 months I've had the intermittent DSC/Brake Warning Light issue. It progressively got worse until they came on permanently 30 seconds or so every time the engine was started. Code reader said Brake Pressure Sensor 1 and 2 at fault. The values for each circuit when the engine was running were 165 bar ! Changed both of these for new ones...no different ! Changed brake fluid...no different ! I then noticed that each time the two warning lights came on I could here a loud click coming from behind the instrument panel. This turned out to be coming from within the ABS Pump Control Unit. I removed the ABS pump and sent it to to ECU Testing for diagnosis. It was promptly returned 3 working days later...no faults ! This really had me scratching my head by now...what was the clicking then ? On the positive side they only charged me £60 or so as no fault found....top stuff. 
So this morning I refitted the ABS pump, changed both brake pressure sensors back to the original two, filled the system with fresh brake fluid and bled it all again. Also removed each wheel speed sensor in turn and cleaned them up before refitting. They were filthy ! :x Covered in rust, mud and both front ones were also thick in magnetised iron filings ! Reconnected the battery, held my breath and turned the key. Now there was 3 yellow warning lights...the ABS now illuminated also...WTF ! Not happy. Connected my C110 and cleared all codes. Still 3 yellows but no clicking from the ABS pump control unit this time. Properly pi**ed off now. I decided to go for a short drive in the hope that the 3 yellows would dissappear. Low and behold just thirty yards up the road all 3 lights vanished.....hoo..bloody..ray !!! Oh the relief ! I've been out 3 or 4 times this afternoon and none of the yellows has returned...thank God ! Hopefully they never will ! So I don't really know which one of these factors by itself or in conjunction with another caused the problem. What's more I don't really care because I'm now a very happy chap.
So this morning I refitted the ABS pump, changed both brake pressure sensors back to the original two, filled the system with fresh brake fluid and bled it all again. Also removed each wheel speed sensor in turn and cleaned them up before refitting. They were filthy ! :x Covered in rust, mud and both front ones were also thick in magnetised iron filings ! Reconnected the battery, held my breath and turned the key. Now there was 3 yellow warning lights...the ABS now illuminated also...WTF ! Not happy. Connected my C110 and cleared all codes. Still 3 yellows but no clicking from the ABS pump control unit this time. Properly pi**ed off now. I decided to go for a short drive in the hope that the 3 yellows would dissappear. Low and behold just thirty yards up the road all 3 lights vanished.....hoo..bloody..ray !!! Oh the relief ! I've been out 3 or 4 times this afternoon and none of the yellows has returned...thank God ! Hopefully they never will ! So I don't really know which one of these factors by itself or in conjunction with another caused the problem. What's more I don't really care because I'm now a very happy chap.
