Hi I had fault develop on what turned out to be the brake light switch .It started by the VSA ligjt coming on and the centre display saying l CHECK SYSTEMS.it would after some time go off .Glyn Hopkins at Chelmsford Essex checked it out with out charging the £65 to plug in the test modual which was very good of the .They diagnosed the brake light switch was the cause , this was correct as although I was unaware my brake lights were not always working .Apparently the switch also data to the ECM .I have replace the switch from Europarts £17.00.and I hope have no more problems . John