2003 X5 4.4i w/ 98k miles. DSC/BRAKE/ABS light came on. Code indicated left wheel speed sensor failed. R/R WSS, lights still on. Swapped WSS from left to right. DSC read under-voltage condition as well (12.5v). Multiple mechanics scratching heads. Local BMW dealer/service center quoted $3.5k to R/R DSC. Another mechanic quoted $1.5K for rebuilt BOSCH OEM although believes that arcing / failing electrical line may be to blame. Car is currently in shop.