Check solenoid, place screwdriver on nut of solenoid. Operate pump. Magnetism in solenoid will draw screwdriver if operating properly. Spool valve maybe stuck. Tap lightly on hex nut and spool valve located on face of solenoid. Retry, if it fails. Remove nut, solenoid and spool valve. Insert small phillips screwdriver into end of valve. Compress moving internal portion of valve 1/4". Repeat several times. Reinstall. Contact your dealer.