If you just got the Ross-Tech software and receive the following code, don't worry.
17087, P07803, Torque Converter/Brake Switch B Circuit Malfunction
The most likely reason why this code comes up is due to the fact that the brake pedal has not been depressed after energizing the ignition. This must be completed once after the ignition is switched on to clear the fault. The Bently has the following note:
Notes for DTC 17087/P0703:
The malfunction is pre-set when the ignition is switched on. The pre-set DTC is erased after the brake pedal has been activated one time if the brake light switch -F- is OK.
Actuate the brake pedal before checking DTC memory so that the pre-set malfunction is erased.