P0503 - VOLVO S60 2005

Question

2005 Volvo S60 2.5l engine The vehicle does not have any symptoms of failure, only appears in message board, that the vehicle was arrested for serious breakdown deve brakes, traction control is disabled and odometer resets to zero miles.
By scanning the vehicle, it reports fault code P0503 VSS sensor intermittent fault, this vehicle has two VSS sensors.

Answer 1

There is a input speed sensor and output sensor 

Service manual does have info how to check it