Header Tank Fuel Low warning light

After about 30 minutes at cruise altitude of 6500 feet, the "header tank low fuel" red light illuminated. I was only operating with main pump on and fuel pressure was at 42.7 psi. I immediately turn on the aux pump and pressure increase to 43.7 psi. Then I started a turn in the direction of the nearest airport. During the turn the light extinguished. The wings were full of fuel. I always only see about 42.7 psi with the main pump running and then always get about 1psi increase with the aux pump on. New Rotax fuel filter installed about 3 hours ago had no affect on fuel pressure. I am new to Rotax ownership. Thanks for any insight on this subject. I was thinking a may need to replace the main pump to get more pressure??

CTLSi 

912is

93 Octane autofuel with No ethanol

270 hrs Total Time