Abs & Dsc Problem! Help Please

[fockviz]

hi thanks for looking....i have a problem with my traction(dsc) and abs unit....the light turns on at times and sometime it doesnt, like it will not turn on when i take a trip to the store then the trip home when i start the car the abs/brake/dsc light turns on(yellowish color). i have a 99 e39 540i6. so then when the abs/brake/dsc lights come on my speedometer would not work. can anyone tell me whats wrong with my car?.all i did is upgraded my wheels to 18" with all new tires. thanks for looking

[youngkang]

I think someone here had same problem and found out that problem was with rear wheel sensor. Get a code reader and check it out.