I found a few links when I searched yahoo with BMW P1721 and BMW P0721.
One indicated the fluid level could be low. It could also be a wiring problem to the transmission output speed sensor.
Another indicated the battery voltage could be too low.
Discounts on new and CPO cars.
Most Dealers offer a parts discount, BMP Design 10% off
Last edited by shanneba; 07-21-2010 at 08:33 PM.