Sometimes you can extend the life of the pump by a couple of years by disassembling the pump and cleaning the orange disk valve and seat that is in the end of the pump.
As the pump wears, graphite powder builds up on the seat of the valve reducing the pressure that the pump can produce.
Place a mark across the sections of the pump so they can be properly re-assembled. Remove 5 screws holding the end of the pump to the electric motor. Disassemble.
You will notice bumps of graphite on the seat. Clean the seat with a Qtip and water (maybe little soap), clean the disk and screen.
Re-assemble and evenly tighten the 5 screws.
The above is for the Bosch pump.