I have had this problem for a while now,after first instance i had the codes read and it revealed left front speed sensor,as i was holiday at the time i had it reset and all was good for a few weeks. When the lights came on there was a very slight thump from underneath (i'm presuming the TC disengaging the front axle) followed by the self level inactive message. I have read on here that the two are unrelated but i find it hard to believe,as every single time i get these lights it is immediately followed by the SLS message. I had the codes read again and it indicated the wheel speed sensor and self level CAN BUS 50. I have bought two brand new wheel speed sensors and fitted them yesterday (the old one were VERY dirty) only for the lights to come back on within five minutes. I read the car again and it says left front wheel speed sensor air gap too large !!! Anybody got any ideas before i clean the old sensors and refit them!!!