A valve device for controlling a pneumatic trailer air suspension system , the valve device comprising: at least one cushion connection connectable to a pneumatic spring cushion of the air suspension system , a supply connection connectable to a compressed air reservoir , and a venting connection connectable to the atmosphere, wherein the valve device has a pneumatically actuable main valve unit , an electrical pilot control unit , and a manual pilot control unit , the electrical pilot control unit and manual pilot control unit are adapted for providing at least one first pilot pressure (p1) to said main valve unit , wherein said main valve unit is adapted to provide at least a cushion pressure (pC) at said cushion connection dependent on the first pilot pressure (P1), wherein the manual pilot control unit comprises a manually operatable camshaft for controlling at least a first valve body , wherein said camshaft at least is rotatable into a driving position (R1), a lowering position (R2) and a lifting position (R3), wherein the valve device has a shaft sensor for directly determining the rotational position of said camshaft , wherein the valve device comprises an electronic control unit connected to said shaft sensor and said electrical pilot control unit , wherein the electronic control unit comprises means for receiving a sensor signal (SR1, SR2, SR3) from said shaft sensor indicative for one of the positions (R1, R2, R3), wherein the electronic control unit comprises means for providing at least a first switching signal (S1) corresponding to the sensor signal (SR1, SR2, SR3) to said electrical pilot control unit , characterized in that said camshaft comprises a sensor portion , said sensor portion comprising a sensible structure , and wherein said sensible structure comprises at least a first, a second, and a third surface , which are formed at different minimum distances to the shaft sensor and the shaft sensor is adapted to measure a distance to said first, second, and third surfaces . at least one cushion connection connectable to a pneumatic spring cushion of the air suspension system , a supply connection connectable to a compressed air reservoir , and a venting connection connectable to the atmosphere, wherein the valve device has a pneumatically actuable main valve unit , an electrical pilot control unit , and a manual pilot control unit , the electrical pilot control unit and manual pilot control unit are adapted for providing at least one first pilot pressure (p1) to said main valve unit , wherein said main valve unit is adapted to provide at least a cushion pressure (pC) at said cushion connection dependent on the first pilot pressure (P1), wherein the manual pilot control unit comprises a manually operatable camshaft for controlling at least a first valve body , wherein said camshaft at least is rotatable into a driving position (R1), a lowering position (R2) and a lifting position (R3), wherein the valve device has a shaft sensor for directly determining the rotational position of said camshaft , wherein the valve device comprises an electronic control unit connected to said shaft sensor and said electrical pilot control unit , wherein the electronic control unit comprises means for receiving a sensor signal (SR1, SR2, SR3) from said shaft sensor indicative for one of the positions (R1, R2, R3), wherein the electronic control unit comprises means for providing at least a first switching signal (S1) corresponding to the sensor signal (SR1, SR2, SR3) to said electrical pilot control unit , characterized in that said camshaft comprises a sensor portion , said sensor portion comprising a sensible structure , and wherein said sensible structure comprises at least a first, a second, and a third surface , which are formed at different minimum distances to the shaft sensor and the shaft sensor is adapted to measure a distance to said first, second, and third surfaces . <EOS>