Combination Meter: Speedometer: Operation
WARNING: This page is about a different car, the 2004 Subaru Forester. However, it is still accessible from the selected car via links, so may be relevant.
MT models: The vehicle speed sensor sends vehicle speed signals (4 pulses per rotation of speed sensor's driven shaft) to the speedometer drive circuit and odometer/trip meter drive circuit in the speedometer.
AT models: The TCM sends vehicle speed signals (4 pulses per rotation of output shaft) to the speedometer drive circuit and odometer/trip meter drive circuit in the speedometer.
NOTE:
Signals from the speed sensor or TCM are also used by the engine control module, automatic transmission control module, etc.