persistant fp fault!?

go to do a load of washing as usual and half way through the cycle it comes up with the fp fault. i have done as suggested and tilted machine at 45 degrees, checked all pipes and filter and just when i think i have solved the problem it still shows the fp fault half way through. i notice that when i take the drainage pipe out of the waste pipe at the back and put it in a bucket at the front of the washer it works. any suggestions? im thinking the pump its self may be on its way out.