Have you checked the air control up on the edge of the spa? There is a control for the Moto Massage Jet, and one for the four small jets just above it. They are usually close together.
Also - is there water coming out of the Moto Massage? If the spa filter is dirty, it will slow the flow way down and can stop the movement of the Moto. If it is real bad it can also stop the jet from moving enough water to draw air.
And - of course - the Diverter Valve must be in the correct position for the Moto to get enough flow to do it's thing.
HTH