DSC Disengaged / Fault – Brake & Traction Control Fault HELP!!
 

I’ve recently had a few repairs done to my 2004 BMW 325i that was involved in a front end collision. While repairing the damage, I installed a BMW M-tech aero kit as well as a sport multi-functional steering wheel with round air bag. Now that the repairs have been completed, the dash shows the DSC to be disengaged with the traction control and the brake light both illuminated in yellow. The ABS light is not illuminated on the dash. I had the fault reset at a local BMW dealership (120.00) and when I got 30 miles away from the dealership, the lights came back on. When I took the car back to the dealership, the service tech told me that they could start replacing parts that could possibly be causing the fault, but that they didn’t know exactly what the faulty part was. Can anyone give me any suggestions as to what parts might cause this fault, how I could test them without just blindly replacing parts, and which part would be at the top of the list of possible culprits?