Possible causes

– Faulty Shaft Speed Sensor
– Shaft Speed Sensor harness is open or shorted
– Shaft Speed Sensor circuit poor electrical connection

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P0794 MAZDA Description

This sensor detects the rotation speed of the counter gear. By comparing the counter gear speed signal with the direct clutch speed sensor signal, the Engine Control Module (ECM) detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions. Thus smooth gear shifting is performed.